


















Care Guide for Bigleaf hydrangea 'Tricolor'


More About How-Tos



Common Pests & Diseases



















- Remove beetles, nymphs, and eggs. Remove all life stages of the beetles and kill them by placing them in a bucket of warm, soapy water. This can be done more easily by placing the bucket under affected leaves and shaking the plant. This method is most effective in the afternoon when leaf beetles are more active. Always dispose of insects in a sealed bag or container to avoid escape and spread.
- Apply organic insecticides. Use naturally-derived insecticides before moving on to synthetic insecticides. Neem oil and pyrethrum are naturally-derived insecticides that should be applied following label instructions.
- Apply synthetic insecticides. Examples of insecticides effective for leaf beetles include carbaryl, permethrin, and bifenthrin. Apply insecticides according to label instructions.

- Regularly check for beetles. To prevent large pest infestations, be proactive about frequently checking plants for pests and removing them quickly.
- Clear debris. Clear weeds and debris to remove areas where these beetles may overwinter and hide.
- Attract natural predators. Birds and other insects, such as wasps and ladybugs, are effective natural predators of leaf beetles. Encourage them to visit by including a diverse array of plants to provide habitat and food. Also, avoid applying broad-spectrum herbicides that can harm and kill beneficial insects.
- Plant aromatic herbs like mint, garlic, or rosemary, as these can repel leaf beetles.







- Apply insecticide. For an organic solution, spray plants with a Bacillus thuringiensis (Bt), which specifically affects the larval stage of moths and butterflies. Be sure to coat plants, since caterpillars need to ingest Bt for it to be effective. This will not harm other insects.
- Spray a chili extract. Chili seeds can be cooked in water to make a spicy spray that caterpillars don't like. Spray this mixture on the plants, but be aware it will also be spicy to humans.
- Introduce beneficial insects. Release beneficial insects to the garden that eat caterpillars, such as parasitic wasps.
- Hand pick. Using gloves, pick off caterpillars on plants and dispose of them in a bucket of soapy water.
- Dust plants with diatomaceous earth. This powder is harmless to humans but irritates caterpillars. Therefore, it will make it difficult for caterpillars to move and eat.

- Monitor plants. Check plants regularly for caterpillar eggs on leaves. If they do not belong to an endangered species, they should be squished.
- Use insect netting. Cover plants with insect netting to prevent butterflies and moths from laying eggs on plants.
- Apply diatomaceous earth. Apply DE to plants early in the season and reapply after rain.
- Encourage plant diversity. This will attract predatory insects including parasitic wasps.






- Wilted, droopy flowers
- Petals and leaves begin to wrinkle
- Brown papery streaks or spots appear on the petals and leaf tips
- Flowerhead shrink in size
- Petal color fades
- Yellowing leaves
- Complete death of the flower



- Water plants according to their needs -- either keep the soil slightly moist or allow the top inch or two to dry out before watering again.
- Fertilize lightly on a consistent basis, depending upon the plant’s growth. Quick-growing plants and those that flower or develop fruit will need more frequent fertilizing than slow-growing plants.
- Purchase plants that are certified disease- or pathogen-free.
- Look for disease-resistant cultivars.
- Isolate plants showing disease symptoms to prevent the spread to neighboring plants.
- Practice good plant hygiene by removing any fallen plant material as soon as possible.






- Pallid spots on colored petals.
- Brown spots on white petals.
- Browning around the petal edges.
- Small spots look water-soaked.
- Spots rapidly enlarge and merge.
- Flowers become limp.
- The entire flower turns light brown, but does not crumble.
- Flowers become slimy at first and then take on a leathery texture.
- A ring of white or gray mycelium can be seen at the base of the petals.



- Apply a preventative dose of fungicide as soon as blooms start to show color on the plant. The preventative can be applied as a soil drench or directly to the flowers on the plant.
- Avoid overhead watering during blooming.
- Remove any leaf litter and dead flowers at the end of the season.
- Cover the ground under infected plants with 4” of fresh organic mulch before winter, taking care not to disturb the infected soil.
- Buy bare-root specimens when available.
- When potted plants are purchased, remove the top layer of potting soil and replace it with fresh mulch.
- Plant cultivars that bloom early in the season before the temperatures get high enough for petal blight pathogens to be spreading.



More Info



Scientific Classification


Related Articles

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Care Guide for Bigleaf hydrangea 'Tricolor'












More About How-Tos

Common Pests & Diseases























- Remove beetles, nymphs, and eggs. Remove all life stages of the beetles and kill them by placing them in a bucket of warm, soapy water. This can be done more easily by placing the bucket under affected leaves and shaking the plant. This method is most effective in the afternoon when leaf beetles are more active. Always dispose of insects in a sealed bag or container to avoid escape and spread.
- Apply organic insecticides. Use naturally-derived insecticides before moving on to synthetic insecticides. Neem oil and pyrethrum are naturally-derived insecticides that should be applied following label instructions.
- Apply synthetic insecticides. Examples of insecticides effective for leaf beetles include carbaryl, permethrin, and bifenthrin. Apply insecticides according to label instructions.

- Regularly check for beetles. To prevent large pest infestations, be proactive about frequently checking plants for pests and removing them quickly.
- Clear debris. Clear weeds and debris to remove areas where these beetles may overwinter and hide.
- Attract natural predators. Birds and other insects, such as wasps and ladybugs, are effective natural predators of leaf beetles. Encourage them to visit by including a diverse array of plants to provide habitat and food. Also, avoid applying broad-spectrum herbicides that can harm and kill beneficial insects.
- Plant aromatic herbs like mint, garlic, or rosemary, as these can repel leaf beetles.
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- Apply insecticide. For an organic solution, spray plants with a Bacillus thuringiensis (Bt), which specifically affects the larval stage of moths and butterflies. Be sure to coat plants, since caterpillars need to ingest Bt for it to be effective. This will not harm other insects.
- Spray a chili extract. Chili seeds can be cooked in water to make a spicy spray that caterpillars don't like. Spray this mixture on the plants, but be aware it will also be spicy to humans.
- Introduce beneficial insects. Release beneficial insects to the garden that eat caterpillars, such as parasitic wasps.
- Hand pick. Using gloves, pick off caterpillars on plants and dispose of them in a bucket of soapy water.
- Dust plants with diatomaceous earth. This powder is harmless to humans but irritates caterpillars. Therefore, it will make it difficult for caterpillars to move and eat.

- Monitor plants. Check plants regularly for caterpillar eggs on leaves. If they do not belong to an endangered species, they should be squished.
- Use insect netting. Cover plants with insect netting to prevent butterflies and moths from laying eggs on plants.
- Apply diatomaceous earth. Apply DE to plants early in the season and reapply after rain.
- Encourage plant diversity. This will attract predatory insects including parasitic wasps.
unlimited guides at your fingertips...






- Wilted, droopy flowers
- Petals and leaves begin to wrinkle
- Brown papery streaks or spots appear on the petals and leaf tips
- Flowerhead shrink in size
- Petal color fades
- Yellowing leaves
- Complete death of the flower



- Water plants according to their needs -- either keep the soil slightly moist or allow the top inch or two to dry out before watering again.
- Fertilize lightly on a consistent basis, depending upon the plant’s growth. Quick-growing plants and those that flower or develop fruit will need more frequent fertilizing than slow-growing plants.
- Purchase plants that are certified disease- or pathogen-free.
- Look for disease-resistant cultivars.
- Isolate plants showing disease symptoms to prevent the spread to neighboring plants.
- Practice good plant hygiene by removing any fallen plant material as soon as possible.
unlimited guides at your fingertips...






- Pallid spots on colored petals.
- Brown spots on white petals.
- Browning around the petal edges.
- Small spots look water-soaked.
- Spots rapidly enlarge and merge.
- Flowers become limp.
- The entire flower turns light brown, but does not crumble.
- Flowers become slimy at first and then take on a leathery texture.
- A ring of white or gray mycelium can be seen at the base of the petals.



- Apply a preventative dose of fungicide as soon as blooms start to show color on the plant. The preventative can be applied as a soil drench or directly to the flowers on the plant.
- Avoid overhead watering during blooming.
- Remove any leaf litter and dead flowers at the end of the season.
- Cover the ground under infected plants with 4” of fresh organic mulch before winter, taking care not to disturb the infected soil.
- Buy bare-root specimens when available.
- When potted plants are purchased, remove the top layer of potting soil and replace it with fresh mulch.
- Plant cultivars that bloom early in the season before the temperatures get high enough for petal blight pathogens to be spreading.
unlimited guides at your fingertips...


More Info



Scientific Classification


Related Articles












unlimited guides at your fingertips...





















