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Add to My Garden Blue cereus
Cereus hexagonus
Also known as: Queen-of-the-night
Blue cereus (Cereus hexagonus) is a tree-like cactus that can grow to 15 m tall. It has a grayish-green twisted stalk with thorns along the five ridges. It blooms from spring to summer with large white blossoms that open at night. Flowers are funnel-shaped and can be up to 25 cm long. Edible fruits are pale red and ripen in fall. Grows best in full sun with well-drained soil.
10 to 13
Hardiness Zones
Care Guide for Blue cereus
Drought-tolerant. Allow the soil to dry completely between watering.
Fertilization once every 2-3 months during the growing season.
Full sun, Partial sun
10 to 13
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Blue cereus
Water
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Sunlight
Full sun
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Questions About Blue cereus
Watering 
Sunlight 
Temperature 
Fertilizing What's the best method to water my Blue cereus?
Another tip when watering this species is to water it from the bottom. This is for the proper absorption of water to the roots, enabling it to circulate the nutrients from the soil towards its whole body. When you accidentally spill water at the top part, this can cause the development of diseases and fungi.
Use sprinklers when you have irrigation systems. Get the small sprinklers if you have Blue cereused in your garden. It's best to get the revolving ones that allow you to change the water delivery patterns whenever you need them. Avoid turning on the sprinkler on windy days. Make sure to use the soak and dry method regardless if the Blue cereus is in a pot or your garden. This will evenly distribute the moisture across the root systems resulting in healthier growth.
Some owners might want to get a built-in drainage system for their succulents. This is where layers of porous materials like recycled glass or hydro stones are placed beneath the soil. They will generally be a reservoir for excess water, so it's important not to pour too much water into these built-in systems.
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What should I do if I water my Blue cereus too much/too little?
When you see that the Blue cereus begins to turn yellow, know that this can be caused by underwatering or overwatering. When the soil is too wet, then there might be the presence of fungal infections. You should allow everything to dry, and you should not overwater.
Also, the browning and dropping symptoms indicate that your plant is getting too much moisture and water. If there's not enough water, the indication can be seen with the yellow tips that can begin to form on stems and branches.
When you're still in the process of buying the Blue cereus, make sure to ask first if the soil is properly draining or sandy. When the topsoil does not properly drain, there's a chance that the plant will likely not receive enough water in the future.
Another thing is that the Blue cereus tends to die when it's constantly getting overwatered and if it's receiving too much rain if planted outside. Use rainwater or distilled water whenever possible as the plants don't like many minerals in their drink.
You can see the squishy stems, drooping growth, and discolored parts that are all signs of too much moisture. It's critical to give the species time to recover and allow the pot to dry. Transfer it to a different container to avoid root rot and prevent it from dripping. If planted outside, you can also transfer it into a pot, especially in the winter, to help it recover.
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How often should I water my Blue cereus?
Most of the time, you only need to water your succulents once every two to three weeks in the summer and spring. During the winter and fall, reduce the watering or avoid this as this plant tends to become dormant.
Let the soil dry completely, and it's always a good idea to lean on the side of underwatering rather than overwatering. When they are in the pot, water deeply at intervals to encourage healthier soil growth.
When they are planted outdoors, never water them lightly as this will result in more shallow root growth. Wait for a few weeks and only give them a drink when the soil around them is too dry.
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How much water does my Blue cereus need?
Water this succulent efficiently and make sure to cover the entire pot. Set a saucer at the bottom of the pot so the roots will get enough moisture. When you see that the soil begins to saturate, take out the saucer immediately. The holes in the pot and the amount of soil will determine the frequency and the quantity of water you should give your plant. A can of water is often more than enough for the Blue cereus especially if they are planted in pots.
When you plant them in the garden or outdoors, you need to include the rainwater they receive. About an inch of rainwater is more than enough to last them for a few weeks, so refrain from watering. When they are outside, you need to water them in the morning with about a gallon of water after you see that the soil is bone dry so the sunlight can help evaporate the excess moisture.
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Why is watering my Blue cereus important?
Watering the Blue cereus will help transport the nutrients that it needs from the soil to the rest of the plant. Without enough moisture, the Blue cereus won't remain healthy or might even become malnourished. Watering should be done when you see some signs that the plant is thirsty. When you're in doubt, you should never overwater as this can be a way to kill them.
The best way to water them is the soak and dry method. When you see that the soil becomes too dry, you should soak them in water until you see that the pot is dripping with water underneath. Then, go for weeks without watering to give the soil a chance to rest.
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How can I ensure that i'm watering my Blue cereus adequately?
Before you give this plant a drink, it's always a good idea to check the soil's moisture levels by poking your finger in it or using a moisture meter. This will tell you whether the soil is already too dry or if there's still moisture. It's a technique used by owners of smaller potted plants to know whether it's time to water or not.
Assess the needs of your Blue cereus and know that it requires watering every two weeks during the summer. You can go as far as three weeks in the hot season before watering this, but in the fall or winter, there should not be any water at all. Allow the soil to dry between irrigations. They can be grown in greenhouses and other warm spots indoors and thrive well. When your plant is getting too much light, you can increase the watering frequency as long as you see that the soil is dry. They can also be grown outdoors, where you will need to water them less. Give it enough water once every three weeks; this should be more than enough. Don't rely alone on irrigations and sprinklers to reach their bases. Use a soaker hose that will hit the ground and spread the water. Make sure it won't hit much of the body of the plant as this can result in diseases.
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Should I adjust the frequency of watering my Blue cereus according to different seasons or climates?
Blue cereus is very tolerant of drought. This means that you don't need to water them very often. Watering frequency should also depend on the climate where you live. In a dry environment, you can make the watering conditions adapt well to your plants' needs. When they are in their early flowering stages, you might want to increase watering to help them grow. When they are receiving enough sunlight, water only in the morning. Specifically, they can be watered once every 10 to 14 days during the summer. You can increase this frequency during times of heat waves and make sure to mist the base from time to time lightly. When it's too cold, you can cut back on watering or once every 21 to 28 days when it begins to cool down.
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Should I adjust the watering frequency during the different growing stages of my Blue cereus?
When you've just repotted the plant, you should wait for a week before you can water your Blue cereus. When it's time to water them, be generous until you see the water coming out of the potholes but don't make it a deluge. When they have already grown and received medium light, you might want to water them once every 2 to 3 weeks since they are very tolerant to drought.
In the winter, you will further need to cut back on watering. The ideal time is to water it once every 3 to 4 weeks as long as the soil does not feel too dry. Winter is their resting season, so they don't consume a lot of energy or grow at this time.
If you grow the plants outdoors, rainwater can be another excellent alternative when you want to hold back on watering. When you live in an area where you don't get much rain, water at least once every three weeks to prevent the soil from drying too much.
In humid locations, there's no need to water a lot. When keeping the Blue cereus indoors, you won't have to keep the moisture high, especially if the plant does not receive too much sunlight. When there's too much moisture and not enough light, this can spell disaster for the succulents.
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What should I be careful with when I water my Blue cereus in different seasons, climates, or during different growing periods?
The Blue cereus growing outdoors can thrive with rainfall, but when it’s planted in a pot, you need to be careful while Blue cereus is still in the growing stage. One way to prevent overwatering is to check the top bottom inches of the soil for moisture. Once again, you need it to be dry so you can water it again. If you're unsure of the amount and the frequency, especially during the growing phase, go with underwatering and slightly increase it when you see a need. It's always a good idea to take a picture of the Blue cereus and note how it looks after watering it. You can take things further by using moisture meters or hygrometers to check the air and soil moisture. These tools are available from various shops and can be valuable when you want to know the readings for humidity and water.
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Should I water my Blue cereus differently when I plant it indoors vs outdoors?
Know that these plants can survive for weeks without any water. This is because they have water storage capacity that can conserve water for a long time. so it will conserve enough water to stay alive even if they are in the wild.
When they are fully grown, water them less since they can survive without water compared to when they were small. You need to give them time to get used to your climate and growing conditions before watering them. If they are indoors, keep them in indirect light and water them less frequently. Avoid using cold water during the winter and months, and you might be overwatering when the plants are located indoors. Give this a rest, especially during the winter and fall.
When they are outdoors, refrain from watering too much. They should be able to get enough humidity, moisture, and rainfall that will keep them alive. Only water when you see that their leaves are becoming droopy and yellowish. Always lean on the side of underwatering as the Blue cereus is very tolerant to dry conditions. They don't like wet feet and might wilt when you water them too much.
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Common Pests & Diseases
Common issues for Blue cereus based on 10 million real cases
Scars
Any light-colored markings that appear on stems but which do not enlarge or multiply are simply scars that have healed.
Solutions: Each source of scarring requires a different approach to help your plant recover. Protect the trunk and leaves from physical damage like scrapes. If pests or disease are the cause of scarring, isolate the plant from others to avoid further spread. Some pests can be removed with organic remedies such as a soft cloth and soapy water solution or diluted isopropyl alcohol spray. Stop sunburn by moving your plant away from direct sunlight and making sure it has the water it needs. Frequent leaf or bud loss may be due to insufficient light or nutrients.
Fruit withering
Fungal infection or normal ripening can cause the fruit to dry out.
Solutions: There are a number of appropriate solutions to control fruit withering: Remove any fruit as soon as it shows any signs of infection. Do not compost. Use a fungicide prior to leaf bud and then as per manufacturers instructions throughout the season.
Brown spot
This infection can cause brown spots or patches to appear on the plant.
Solutions: In minor cases of brown spot, there isn’t any need to treat the disease. However, if much of the foliage is affected and defoliation occurs, the plant will benefit from getting rid of the infection. It is recommended to start by applying organic treatment options, working up to the more potent synthetic, chemical fungicides if necessary. Organic options won’t kill the fungus, but will prevent it from spreading. Dissolve ½ teaspoon of baking soda and one teaspoon of liquid soap in a gallon of water. Using a spray bottle, spray on tops and bottoms of leaves until the mixture drips off. Repeat every two weeks until existing spots stop enlarging and new spots no longer appear. Spray a copper-based fungicidal soap on the leaves, coating the top and bottom leaf surfaces. Reapply as directed on the product label. Copper penetrates the leaf surface and prevents germination of spores so the fungus cannot spread. Apply an all-purpose fungicide to the entire plant, following the label instructions carefully.
Plant dried up
The entire plant may dry out due to dieback or normal seasonal dormancy.
Solutions: The solution for a dried out plant depends on the cause, so determine the cause before selecting a treatment method. Adjust your watering: Stick your finger in the soil near the roots. If it feels bone dry or overly saturated, you need to adjust your watering frequency accordingly. Prune back dead foliage: Snip off any brown stems and leaves on the plant to make space for new growth. This encourages the roots to send up fresh stems. Move to a proper environment. This may involve decreasing or increasing sun exposure, depending on the species. Decrease fertilizer applications. If you have applied too much fertilizer, you can repot plants with fresh potting soil. Wait. If your plant has dried out as daylight is decreasing, it is entering dormancy. Decrease watering and wait until the plant resumes growth.
Low light
A lack of sunlight will cause the stems and leaves to elongate and appear lighter in color.
Solutions: Low light can only be addressed by increasing light availability, and these measures will only stop further etoliation; current distortion cannot be reversed. Move plant to a position where it receives more light. Check the requirements for specific species, as too much sunlight can cause a plant to burn. Introduce appropriate artificial lighting. Some people choose to prune the longest stems so the plant can concentrate on healthy new growth under the improved lighting.
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Scars
Any light-colored markings that appear on stems but which do not enlarge or multiply are simply scars that have healed.
Symptom Analysis
Scars form when the plant repairs wounds. They can be the result of people or pets passing by and scraping the plant. Once the underlying issue is resolved, the plant will heal but a scar may remain.
Pests and pathogens can also cause scarring. Insects may attack the plant for a meal, resulting in extensive scarring when a few invaders turn into an infestation. Diseases such as fungus and bacteria can weaken the plant, causing brown spots, mushy areas, or blisters that lead to scars.
Scars occur on stems when a leaf or bud has been lost and the plant has healed. The harder tissue is like a scab that protects a wound.
On other occasions, scars can signal problems from environmental conditions, such as overexposure to sunlight or heat. It might surprise you to know that plants can suffer from sunburn, even desert dwellers like cactus!
Solutions
Each source of scarring requires a different approach to help your plant recover.
- Protect the trunk and leaves from physical damage like scrapes.
- If pests or disease are the cause of scarring, isolate the plant from others to avoid further spread. Some pests can be removed with organic remedies such as a soft cloth and soapy water solution or diluted isopropyl alcohol spray.
- Stop sunburn by moving your plant away from direct sunlight and making sure it has the water it needs.
- Frequent leaf or bud loss may be due to insufficient light or nutrients.
Prevention
Preventing some sources of scarring is easier than others, but all start with careful attention to your plants once you decide to bring them home.
- Review specific guidelines for your plant, including soil drainage, watering, and fertilizer requirements.
- Inspect plants before planting and use sterile pots and fresh potting soil or media to limit transfer of fungi or bacteria.
- Once established, check your plants regularly for signs of scarring or the presence of pests, as it is better to catch problems as early as possible.
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Fruit withering
Fungal infection or normal ripening can cause the fruit to dry out.
Overview
Fruit withering is common on many tree fruits, including apples, pears, peaches, cherries, and plums, as well as fruiting shrubs. It is caused by a fungal pathogen and will result in wrinkled and desiccated fruit.
Symptom Analysis
Here are the most common symptoms in the order that they are likely to occur.
- Both leaves and blossom on the tips of branches will go brown and wither.
- Gray powdery patches will appear on infected leaves and flowers, and this will be most apparent after rain.
- Any fruit that does appear will turn wrinkled and fail to develop.
- Branch tips begin to die, progressing back to larger branches, causing general deterioration of the tree or plant.
Disease Cause
The withering is caused by one of two fungal pathogens, one called Monilina laxa and the other called M. fructigen. The spores overwinter on infected plant material and are then spread the following spring by wind, rain, or animal vectors. The problem will start to become noticeable in mid-spring, but will increase in severity as summer progresses and the fungus grows. If not addressed, the disease will intensify and spread to other plants in the vicinity.
Solutions
There are a number of appropriate solutions to control fruit withering:
- Remove any fruit as soon as it shows any signs of infection. Do not compost.
- Use a fungicide prior to leaf bud and then as per manufacturers instructions throughout the season.
Prevention
Preventative measures include:
- Ensuring adequate spacing between plants or trees.
- Staking plants that are prone to tumbling to prevent moisture or humidity build up.
- Prune correctly so that there is adequate air movement and remove any dead or diseased branches that may carry spores.
- Practice good plant hygiene by removing fallen material and destroying it as soon as possible.
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Brown spot
This infection can cause brown spots or patches to appear on the plant.
Overview
Discolored spots on the foliage of plants are one of the most common disease problems people observe. These spots are caused by fungal and bacterial diseases, with most infections related to a fungal pathogen.
Brown spot can occurs on all houseplants, flowering ornamentals, vegetable plants, and leaves of trees, bushes, and shrubs. No plants are resistant to it, and the problem is worse in warm, wet environments. It can occur at any point in the life stage as long as leaves are present.
Small brownish spots appear on the foliage and enlarge as the disease progresses. In severe cases, the plant or tree is weakened when the lesions interrupt photosynthesis or cause defoliation.
Symptom Analysis
In most cases, brown spot only affects a small percentage of the whole plant, appearing on a small amount of the leaves. A small infection only puts minor stress on the plant. However, if left untreated and the disease progresses over numerous seasons, it will severely impact the health and productivity of the infected specimen.
- Sporulation begins (reproduction of the fungal spores), and tiny spots appear on leaves.
- Placement is often random and scattered as diseases are spread through raindrops.
- May appear on lower leaves and the interior of the plant where humidity is higher.
- Brown spots enlarge and grow large enough to touch neighboring spots to form a more prominent blotch.
- Leaf margins may turn yellow.
- Tiny black dots (fruiting bodies of the fungi) appear in the dead spots.
- Blotches grow in size until the entire leaf is brown.
- The leaf falls off the plant.
Severe Symptoms
- Partial or complete premature defoliation
- Reduced growth
- Increased susceptibility to pests and other diseases
Disease Cause
Brown spot, or leaf spot, is a common descriptive term given to several diseases affecting the leaves of plants and trees. Around 85% of diseases exhibiting leaf spots are due to fungus or fungus-like organisms. Sometimes brown spot is caused by a bacterial infection, or insect activity with similar symptoms.
When conditions are warm and the leaf surfaces are wet, fungal spores being transported by wind or rain land on the surface and cling to it. They do not rupture the cell walls but grow in the space between the plant plasma membrane and the plant cell wall. As the spores reproduce, they release toxins and enzymes that cause necrotic spots (i.e., dead tissue) on the leaves, allowing the fungi to consume the products released when the cells degrade.
Solutions
In minor cases of brown spot, there isn’t any need to treat the disease. However, if much of the foliage is affected and defoliation occurs, the plant will benefit from getting rid of the infection. It is recommended to start by applying organic treatment options, working up to the more potent synthetic, chemical fungicides if necessary.
Organic options won’t kill the fungus, but will prevent it from spreading.
- Dissolve ½ teaspoon of baking soda and one teaspoon of liquid soap in a gallon of water. Using a spray bottle, spray on tops and bottoms of leaves until the mixture drips off. Repeat every two weeks until existing spots stop enlarging and new spots no longer appear.
- Spray a copper-based fungicidal soap on the leaves, coating the top and bottom leaf surfaces. Reapply as directed on the product label. Copper penetrates the leaf surface and prevents germination of spores so the fungus cannot spread.
- Apply an all-purpose fungicide to the entire plant, following the label instructions carefully.
Prevention
Like many other diseases, it is easier to prevent brown spot than cure it, and this is done through cultural practices.
- Clear fall leaves from the ground before winter to minimize places where fungi and bacteria can overwinter.
- Maintain good air movement between plants through proper plant spacing.
- Increase air circulation through the center of plants through pruning.
- Thoroughly clean all pruning tools after working with diseased plants.
- Never dispose of disease plant material in a compost pile.
- Avoid overhead watering to keep moisture off of the foliage.
- Keep plants healthy by providing adequate sunlight, water, and fertilizer.
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Plant dried up
The entire plant may dry out due to dieback or normal seasonal dormancy.
Symptom Analysis
Your plant has dried out and turned brown. It might be starting to wilt, with no noticeable green around the stems and leaves. Touch the leaves, and they may crinkle under your fingers.
Possible causes of a dried out plant include:
- Not enough water. A lack of water will lead to dry plant tissue.
- Too much water. Watering too much can lead to root rot which makes the plant struggle to take up water. Rotted, mushy roots are a sign of overeating.
- Entering dormancy. As perennial plants enter their resting period known as dormancy, their leaves dry out and may fall off. This happens during decreasing day length.
- Exposure to herbicides and other toxic substances. If a plant is hit with a large dose herbicide or other toxic chemical, the plant will turn brown.
- Too much fertility. An excess of fertilizer can prevent plants from taking up water, leading to drying.
- Improper sun exposure. Just like humans, plants can get sunburn by intense, direct light. Plants can also dry out if they don’t receive enough light.
To determine whether the plant is still alive and can be saved, you can:
- Bend a stem. If the stem is pliable, the plant is still alive. If the stem breaks, the plant is dead.
- Gently scratch the stem with your fingernail for signs of green inside. If your plant is dead, the stem will be brittle and brown throughout.
- Cut the stems back a little bit a time for visible green growth. If none of the stems have visible green growth, the plant is dead.
Solutions
The solution for a dried out plant depends on the cause, so determine the cause before selecting a treatment method.
- Adjust your watering: Stick your finger in the soil near the roots. If it feels bone dry or overly saturated, you need to adjust your watering frequency accordingly.
- Prune back dead foliage: Snip off any brown stems and leaves on the plant to make space for new growth. This encourages the roots to send up fresh stems.
- Move to a proper environment. This may involve decreasing or increasing sun exposure, depending on the species.
- Decrease fertilizer applications. If you have applied too much fertilizer, you can repot plants with fresh potting soil.
- Wait. If your plant has dried out as daylight is decreasing, it is entering dormancy. Decrease watering and wait until the plant resumes growth.
Prevention
Prevention involves providing your plant with the proper environment.
- Provide the proper amount of water. The amount of water depends on a plant’s size, species, and environment. A general rule is to allow soil to dry out between waterings.
- Place plants in the proper environment. Provide the proper hours of sun and temperature for your individual plant.
- Provide proper fertility. Most plants only need to be fertilized once or twice a year; don’t overapply.
- Keep plants free from toxic substances. Keep herbicides and toxic household chemicals away from your plants.
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Low light
A lack of sunlight will cause the stems and leaves to elongate and appear lighter in color.
Overview
All plants require light, and if they do not receive it in the quantities that they require this distorts their growth in a process known as etiolation. In essence, etiolated plants are diverting all of their energy to growing taller in a desperate attempt to reach a position where they can meet their light requirements. Many other growth factors are harmed by this, and so light-deprived plants can become weak and distorted until they are almost unrecognizable. Low light symptoms are most commonly seen in houseplants, but outdoor specimens can also be affected.
Symptom Analysis
Although symptoms will vary in different plants, the general symptoms of low light are easy to spot.
- Plant stems grow tall and lanky.
- There are less leaves, and both leaves and stems tend to be pale and insipid looking. This is due to a shortage of chlorophyll.
- All plant parts become weakened and may droop, as energy is diverted toward too-fast growth as the plant stretches itself toward any source of light.
Disease Cause
Plants need sunlight in varying amounts for photosynthesis – a process that produces energy for growth and fruit and flower production. Low light causes a plant to divert all energy to upward (apical) growth in order to find better light. Plant hormones called auxins are transported from the actively-growing tip of the plant downwards, to suppress lateral growth. A drop in cellular pH triggers expansins, nonenzymatic cell wall proteins, to loosen cell walls and allow them to elongate. This elongation results in the abnormal lengthening of stems, especially internodes, or plant "legginess" which is observed in etoliated plants.
Solutions
Low light can only be addressed by increasing light availability, and these measures will only stop further etoliation; current distortion cannot be reversed.
- Move plant to a position where it receives more light. Check the requirements for specific species, as too much sunlight can cause a plant to burn.
- Introduce appropriate artificial lighting.
- Some people choose to prune the longest stems so the plant can concentrate on healthy new growth under the improved lighting.
Prevention
To avoid etiolation, provide an adequate amount of light from the beginning.
- Choose a location that matches each plant's ideal light needs. Many indoor plants do best in or near a south-facing window, which will provide the longest hours of sunlight. Flowering plants and those with colored leaves typically need more light than purely-green plants, as photosynthesis occurs in the green portions of leaves.
- Select plants with light needs that match a location's conditions. Some cultivars and varieties require less light than others.
- Use a grow light. Darker locations may require artificial illumination. A grow light may also become more necessary during winter, when sunlit hours are at their shortest.
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Distribution Map
Native
Cultivated
Invasive
Potentially invasive
Exotic
No species reported
More Info
Plant Type
Tree, Shrub
Flower Color
White
Green
Name story
Lady of the night cactus
The alluring and slightly racy common name likely alludes to the fact that this is one of many night-blooming cacti. “Cereus” is derived from Greek and Latin words for “wax” or “candle”, a reference to the tall, columnar growth of these cacti. The stem is formed of six angles, hence the specific epithet “hexagonus”.
Scientific Classification
Phylum
Vascular plants Class
Dicotyledons Order
Pinks, cacti, and allies Family
Cactuses Genus
Cereus Species
Blue cereus 
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Add to My Garden Blue cereus
Cereus hexagonus
Also known as: Queen-of-the-night
Blue cereus (Cereus hexagonus) is a tree-like cactus that can grow to 15 m tall. It has a grayish-green twisted stalk with thorns along the five ridges. It blooms from spring to summer with large white blossoms that open at night. Flowers are funnel-shaped and can be up to 25 cm long. Edible fruits are pale red and ripen in fall. Grows best in full sun with well-drained soil.
10 to 13
Hardiness Zones
Care Guide for Blue cereus
Water
Drought-tolerant. Allow the soil to dry completely between watering.
Fertilization
Fertilization once every 2-3 months during the growing season.
Sunlight
Full sun, Partial sun
Hardiness Zones
10 to 13
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Questions About Blue cereus
Watering Sunlight Temperature Fertilizing What's the best method to water my Blue cereus?
What should I do if I water my Blue cereus too much/too little?
How often should I water my Blue cereus?
How much water does my Blue cereus need?
Why is watering my Blue cereus important?
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Keep your plants happy and healthy with our guide to watering, lighting, feeding and more.
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More Questions People Also Ask
Common Pests & Diseases
Common issues for Blue cereus based on 10 million real cases
Scars
Any light-colored markings that appear on stems but which do not enlarge or multiply are simply scars that have healed.
Solutions: Each source of scarring requires a different approach to help your plant recover. Protect the trunk and leaves from physical damage like scrapes. If pests or disease are the cause of scarring, isolate the plant from others to avoid further spread. Some pests can be removed with organic remedies such as a soft cloth and soapy water solution or diluted isopropyl alcohol spray. Stop sunburn by moving your plant away from direct sunlight and making sure it has the water it needs. Frequent leaf or bud loss may be due to insufficient light or nutrients.
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Fruit withering
Fungal infection or normal ripening can cause the fruit to dry out.
Solutions: There are a number of appropriate solutions to control fruit withering: Remove any fruit as soon as it shows any signs of infection. Do not compost. Use a fungicide prior to leaf bud and then as per manufacturers instructions throughout the season.
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Brown spot
This infection can cause brown spots or patches to appear on the plant.
Solutions: In minor cases of brown spot, there isn’t any need to treat the disease. However, if much of the foliage is affected and defoliation occurs, the plant will benefit from getting rid of the infection. It is recommended to start by applying organic treatment options, working up to the more potent synthetic, chemical fungicides if necessary. Organic options won’t kill the fungus, but will prevent it from spreading. Dissolve ½ teaspoon of baking soda and one teaspoon of liquid soap in a gallon of water. Using a spray bottle, spray on tops and bottoms of leaves until the mixture drips off. Repeat every two weeks until existing spots stop enlarging and new spots no longer appear. Spray a copper-based fungicidal soap on the leaves, coating the top and bottom leaf surfaces. Reapply as directed on the product label. Copper penetrates the leaf surface and prevents germination of spores so the fungus cannot spread. Apply an all-purpose fungicide to the entire plant, following the label instructions carefully.
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Plant dried up
The entire plant may dry out due to dieback or normal seasonal dormancy.
Solutions: The solution for a dried out plant depends on the cause, so determine the cause before selecting a treatment method. Adjust your watering: Stick your finger in the soil near the roots. If it feels bone dry or overly saturated, you need to adjust your watering frequency accordingly. Prune back dead foliage: Snip off any brown stems and leaves on the plant to make space for new growth. This encourages the roots to send up fresh stems. Move to a proper environment. This may involve decreasing or increasing sun exposure, depending on the species. Decrease fertilizer applications. If you have applied too much fertilizer, you can repot plants with fresh potting soil. Wait. If your plant has dried out as daylight is decreasing, it is entering dormancy. Decrease watering and wait until the plant resumes growth.
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Low light
A lack of sunlight will cause the stems and leaves to elongate and appear lighter in color.
Solutions: Low light can only be addressed by increasing light availability, and these measures will only stop further etoliation; current distortion cannot be reversed. Move plant to a position where it receives more light. Check the requirements for specific species, as too much sunlight can cause a plant to burn. Introduce appropriate artificial lighting. Some people choose to prune the longest stems so the plant can concentrate on healthy new growth under the improved lighting.
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Scars
Any light-colored markings that appear on stems but which do not enlarge or multiply are simply scars that have healed.
Symptom Analysis
Scars form when the plant repairs wounds. They can be the result of people or pets passing by and scraping the plant. Once the underlying issue is resolved, the plant will heal but a scar may remain.
Pests and pathogens can also cause scarring. Insects may attack the plant for a meal, resulting in extensive scarring when a few invaders turn into an infestation. Diseases such as fungus and bacteria can weaken the plant, causing brown spots, mushy areas, or blisters that lead to scars.
Scars occur on stems when a leaf or bud has been lost and the plant has healed. The harder tissue is like a scab that protects a wound.
On other occasions, scars can signal problems from environmental conditions, such as overexposure to sunlight or heat. It might surprise you to know that plants can suffer from sunburn, even desert dwellers like cactus!
Solutions
Each source of scarring requires a different approach to help your plant recover.
- Protect the trunk and leaves from physical damage like scrapes.
- If pests or disease are the cause of scarring, isolate the plant from others to avoid further spread. Some pests can be removed with organic remedies such as a soft cloth and soapy water solution or diluted isopropyl alcohol spray.
- Stop sunburn by moving your plant away from direct sunlight and making sure it has the water it needs.
- Frequent leaf or bud loss may be due to insufficient light or nutrients.
Prevention
Preventing some sources of scarring is easier than others, but all start with careful attention to your plants once you decide to bring them home.
- Review specific guidelines for your plant, including soil drainage, watering, and fertilizer requirements.
- Inspect plants before planting and use sterile pots and fresh potting soil or media to limit transfer of fungi or bacteria.
- Once established, check your plants regularly for signs of scarring or the presence of pests, as it is better to catch problems as early as possible.
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Fruit withering
Fungal infection or normal ripening can cause the fruit to dry out.
Overview
Fruit withering is common on many tree fruits, including apples, pears, peaches, cherries, and plums, as well as fruiting shrubs. It is caused by a fungal pathogen and will result in wrinkled and desiccated fruit.
Symptom Analysis
Here are the most common symptoms in the order that they are likely to occur.
- Both leaves and blossom on the tips of branches will go brown and wither.
- Gray powdery patches will appear on infected leaves and flowers, and this will be most apparent after rain.
- Any fruit that does appear will turn wrinkled and fail to develop.
- Branch tips begin to die, progressing back to larger branches, causing general deterioration of the tree or plant.
Disease Cause
The withering is caused by one of two fungal pathogens, one called Monilina laxa and the other called M. fructigen. The spores overwinter on infected plant material and are then spread the following spring by wind, rain, or animal vectors. The problem will start to become noticeable in mid-spring, but will increase in severity as summer progresses and the fungus grows. If not addressed, the disease will intensify and spread to other plants in the vicinity.
Solutions
There are a number of appropriate solutions to control fruit withering:
- Remove any fruit as soon as it shows any signs of infection. Do not compost.
- Use a fungicide prior to leaf bud and then as per manufacturers instructions throughout the season.
Prevention
Preventative measures include:
- Ensuring adequate spacing between plants or trees.
- Staking plants that are prone to tumbling to prevent moisture or humidity build up.
- Prune correctly so that there is adequate air movement and remove any dead or diseased branches that may carry spores.
- Practice good plant hygiene by removing fallen material and destroying it as soon as possible.
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Brown spot
This infection can cause brown spots or patches to appear on the plant.
Overview
Discolored spots on the foliage of plants are one of the most common disease problems people observe. These spots are caused by fungal and bacterial diseases, with most infections related to a fungal pathogen.
Brown spot can occurs on all houseplants, flowering ornamentals, vegetable plants, and leaves of trees, bushes, and shrubs. No plants are resistant to it, and the problem is worse in warm, wet environments. It can occur at any point in the life stage as long as leaves are present.
Small brownish spots appear on the foliage and enlarge as the disease progresses. In severe cases, the plant or tree is weakened when the lesions interrupt photosynthesis or cause defoliation.
Symptom Analysis
In most cases, brown spot only affects a small percentage of the whole plant, appearing on a small amount of the leaves. A small infection only puts minor stress on the plant. However, if left untreated and the disease progresses over numerous seasons, it will severely impact the health and productivity of the infected specimen.
- Sporulation begins (reproduction of the fungal spores), and tiny spots appear on leaves.
- Placement is often random and scattered as diseases are spread through raindrops.
- May appear on lower leaves and the interior of the plant where humidity is higher.
- Brown spots enlarge and grow large enough to touch neighboring spots to form a more prominent blotch.
- Leaf margins may turn yellow.
- Tiny black dots (fruiting bodies of the fungi) appear in the dead spots.
- Blotches grow in size until the entire leaf is brown.
- The leaf falls off the plant.
Severe Symptoms
- Partial or complete premature defoliation
- Reduced growth
- Increased susceptibility to pests and other diseases
Disease Cause
Brown spot, or leaf spot, is a common descriptive term given to several diseases affecting the leaves of plants and trees. Around 85% of diseases exhibiting leaf spots are due to fungus or fungus-like organisms. Sometimes brown spot is caused by a bacterial infection, or insect activity with similar symptoms.
When conditions are warm and the leaf surfaces are wet, fungal spores being transported by wind or rain land on the surface and cling to it. They do not rupture the cell walls but grow in the space between the plant plasma membrane and the plant cell wall. As the spores reproduce, they release toxins and enzymes that cause necrotic spots (i.e., dead tissue) on the leaves, allowing the fungi to consume the products released when the cells degrade.
Solutions
In minor cases of brown spot, there isn’t any need to treat the disease. However, if much of the foliage is affected and defoliation occurs, the plant will benefit from getting rid of the infection. It is recommended to start by applying organic treatment options, working up to the more potent synthetic, chemical fungicides if necessary.
Organic options won’t kill the fungus, but will prevent it from spreading.
- Dissolve ½ teaspoon of baking soda and one teaspoon of liquid soap in a gallon of water. Using a spray bottle, spray on tops and bottoms of leaves until the mixture drips off. Repeat every two weeks until existing spots stop enlarging and new spots no longer appear.
- Spray a copper-based fungicidal soap on the leaves, coating the top and bottom leaf surfaces. Reapply as directed on the product label. Copper penetrates the leaf surface and prevents germination of spores so the fungus cannot spread.
- Apply an all-purpose fungicide to the entire plant, following the label instructions carefully.
Prevention
Like many other diseases, it is easier to prevent brown spot than cure it, and this is done through cultural practices.
- Clear fall leaves from the ground before winter to minimize places where fungi and bacteria can overwinter.
- Maintain good air movement between plants through proper plant spacing.
- Increase air circulation through the center of plants through pruning.
- Thoroughly clean all pruning tools after working with diseased plants.
- Never dispose of disease plant material in a compost pile.
- Avoid overhead watering to keep moisture off of the foliage.
- Keep plants healthy by providing adequate sunlight, water, and fertilizer.
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Plant dried up
The entire plant may dry out due to dieback or normal seasonal dormancy.
Symptom Analysis
Your plant has dried out and turned brown. It might be starting to wilt, with no noticeable green around the stems and leaves. Touch the leaves, and they may crinkle under your fingers.
Possible causes of a dried out plant include:
- Not enough water. A lack of water will lead to dry plant tissue.
- Too much water. Watering too much can lead to root rot which makes the plant struggle to take up water. Rotted, mushy roots are a sign of overeating.
- Entering dormancy. As perennial plants enter their resting period known as dormancy, their leaves dry out and may fall off. This happens during decreasing day length.
- Exposure to herbicides and other toxic substances. If a plant is hit with a large dose herbicide or other toxic chemical, the plant will turn brown.
- Too much fertility. An excess of fertilizer can prevent plants from taking up water, leading to drying.
- Improper sun exposure. Just like humans, plants can get sunburn by intense, direct light. Plants can also dry out if they don’t receive enough light.
To determine whether the plant is still alive and can be saved, you can:
- Bend a stem. If the stem is pliable, the plant is still alive. If the stem breaks, the plant is dead.
- Gently scratch the stem with your fingernail for signs of green inside. If your plant is dead, the stem will be brittle and brown throughout.
- Cut the stems back a little bit a time for visible green growth. If none of the stems have visible green growth, the plant is dead.
Solutions
The solution for a dried out plant depends on the cause, so determine the cause before selecting a treatment method.
- Adjust your watering: Stick your finger in the soil near the roots. If it feels bone dry or overly saturated, you need to adjust your watering frequency accordingly.
- Prune back dead foliage: Snip off any brown stems and leaves on the plant to make space for new growth. This encourages the roots to send up fresh stems.
- Move to a proper environment. This may involve decreasing or increasing sun exposure, depending on the species.
- Decrease fertilizer applications. If you have applied too much fertilizer, you can repot plants with fresh potting soil.
- Wait. If your plant has dried out as daylight is decreasing, it is entering dormancy. Decrease watering and wait until the plant resumes growth.
Prevention
Prevention involves providing your plant with the proper environment.
- Provide the proper amount of water. The amount of water depends on a plant’s size, species, and environment. A general rule is to allow soil to dry out between waterings.
- Place plants in the proper environment. Provide the proper hours of sun and temperature for your individual plant.
- Provide proper fertility. Most plants only need to be fertilized once or twice a year; don’t overapply.
- Keep plants free from toxic substances. Keep herbicides and toxic household chemicals away from your plants.
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Low light
A lack of sunlight will cause the stems and leaves to elongate and appear lighter in color.
Overview
All plants require light, and if they do not receive it in the quantities that they require this distorts their growth in a process known as etiolation. In essence, etiolated plants are diverting all of their energy to growing taller in a desperate attempt to reach a position where they can meet their light requirements. Many other growth factors are harmed by this, and so light-deprived plants can become weak and distorted until they are almost unrecognizable. Low light symptoms are most commonly seen in houseplants, but outdoor specimens can also be affected.
Symptom Analysis
Although symptoms will vary in different plants, the general symptoms of low light are easy to spot.
- Plant stems grow tall and lanky.
- There are less leaves, and both leaves and stems tend to be pale and insipid looking. This is due to a shortage of chlorophyll.
- All plant parts become weakened and may droop, as energy is diverted toward too-fast growth as the plant stretches itself toward any source of light.
Disease Cause
Plants need sunlight in varying amounts for photosynthesis – a process that produces energy for growth and fruit and flower production. Low light causes a plant to divert all energy to upward (apical) growth in order to find better light. Plant hormones called auxins are transported from the actively-growing tip of the plant downwards, to suppress lateral growth. A drop in cellular pH triggers expansins, nonenzymatic cell wall proteins, to loosen cell walls and allow them to elongate. This elongation results in the abnormal lengthening of stems, especially internodes, or plant "legginess" which is observed in etoliated plants.
Solutions
Low light can only be addressed by increasing light availability, and these measures will only stop further etoliation; current distortion cannot be reversed.
- Move plant to a position where it receives more light. Check the requirements for specific species, as too much sunlight can cause a plant to burn.
- Introduce appropriate artificial lighting.
- Some people choose to prune the longest stems so the plant can concentrate on healthy new growth under the improved lighting.
Prevention
To avoid etiolation, provide an adequate amount of light from the beginning.
- Choose a location that matches each plant's ideal light needs. Many indoor plants do best in or near a south-facing window, which will provide the longest hours of sunlight. Flowering plants and those with colored leaves typically need more light than purely-green plants, as photosynthesis occurs in the green portions of leaves.
- Select plants with light needs that match a location's conditions. Some cultivars and varieties require less light than others.
- Use a grow light. Darker locations may require artificial illumination. A grow light may also become more necessary during winter, when sunlit hours are at their shortest.
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Distribution Map
Map
Native
Cultivated
Invasive
Potentially invasive
Exotic
No species reported
More Info
Plant Type
Tree, Shrub
Flower Color
White
Green
Name story
Lady of the night cactus
The alluring and slightly racy common name likely alludes to the fact that this is one of many night-blooming cacti. “Cereus” is derived from Greek and Latin words for “wax” or “candle”, a reference to the tall, columnar growth of these cacti. The stem is formed of six angles, hence the specific epithet “hexagonus”.
Scientific Classification
Phylum
Vascular plants Class
Dicotyledons Order
Pinks, cacti, and allies Family
Cactuses Genus
Cereus Species
Blue cereus 
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