Purple toadflax (Linaria purpurea) Care Guide
Found everywhere from European woodlands to the vast grassy fields of Siberia, the purple toadflax is very adaptable. With so many varieties, both artificially-produced and naturally-occurring, this versatile plant does well in every part of the garden, but is most commonly used in beds and borders. It can also be grown successfully indoors. Whichever you choose, this is one of the easiest plants out there to care for. It usually grows up to 1.2 m tall and blooms in a variety of different patterned colors, including combinations of purples, yellows, and pinks.
Quick Care Guides
Water and Hardiness
The purple toadflax is a hardy plant that is native to temperate zones, and will often behave differently in various climates. It is able to tolerate temperatures down to -29 ℃. While young, the purple toadflax requires constant moisture, but, once established, it becomes quite a drought-tolerant plant. In fact, an established plant can even grow from a stone wall!
The purple toadflax will grow in most soil types, but does best in a well-drained, sandy substrate. It isn't fussy about pH and is able to withstand acidic (6.1 to 6.5), alkaline (7.6 to 7.8), and neutral (6.6 to 7.5) soil types.
The purple toadflax is easily planted and propagated from seed. Sow directly into the soil just after your last frost, or earlier indoors to then be transplanted in the spring. Sow shallow and lightly cover. Keep the soil moist during the germination process.
Although the purple toadflax is drought-resistant when mature, it will require your care until established. Keep the soil moist during this period but pay attention to drainage; the only thing that can really hinder this hardy plant is damp soil caused by poor drainage. Once established, a regular 2.5 cm of rainwater weekly (even less) will suffice.
The purple toadflax doesn't need any fertilizer to flourish. While fertilizing this plant will likely encourage lush green leaves, it will reduce blooming. However, mixing your planting soil with some organic compost will give your plant a few extra nutrients when it needs it the most (while establishing), while also significantly improving soil drainage.
The purple toadflax does not need much pruning, but will require a certain amount of maintenance to prevent it from quickly spreading throughout your garden. It is a very successful invasive plant because it is effective in both seed and vegetative reproduction. In fact, it seeds so readily that one purple toadflax plant during the course of its lifetime can produce up to 500,000 seeds.
Pinch or remove flowers at the end of the flowering season, just before they start producing seeds. Alternatively, after blooming, cut down the plants by 2/3 to encourage new growth. If you already have some plants that have spread out of their original location, manual removal with repeated digging up of the roots is a good course of action.
Mypurple toadflax keeps producing lots of foliage, but almost no flowers. Why is this happening?
this sounds like a case of over-fertilization. Purple toadflax does not require additional nourishment and will grow very happily in poor soils. When given much additional feed, especially one rich in nitrogen, the plant will start to produce lush green leaves but cut back on its blooms. Don't worry, just stop fertilizing it and expect nice blooms the following season.
The leaves on my purple toadflax are losing color and are drooping. Why is this happening?
this is probably a case of overwatering. Poor drainage is basically the only way you can destroy these hardy plants. Check the drainage of your soil and mix in some compost to improve it if needed. Additionally, if your garden usually receives 2.5 cm of rain weekly, make sure that you only water your purple toadflax during periods of drought.
Pests and Diseases
Powdery Mildew on the purple toadflax is often caused by fungi from the Microsphaera genus. The first symptoms often include a white, dusty film forming on the leaves, which, over time, usually turns darker in color. If untreated, the film will start spreading and form on the entire plant (all foliage, stems, and flowers).
Root rot is caused by a fungus, often from the Phytophthora genus, and is a result of excess water in the soil. The fungus invades the cambium tissue of the purple toadflax and causes the plant to basically starve out, due to root system failure. Symptoms include discoloration and wilting of the leaves, stunted growth, and darkened root tissue. this is a serious fungal disease and if not treated from the start, it may result in plant death.
Infected roots must be removed using sharp, clean tools. Cut large portions of the root to ensure the stop of the spread. Clean tools between cuts so as to not cross-contaminate the healthy roots, as well as the plant container. Use a systemic fertilizer if you must, but with caution.
Aphids feed on the sap of plant stems and leaves. When feeding, they excrete sticky substances that can attract ants and other insects. Aphids can also be vectors of several fungal, bacterial and viral diseases and should not be left untreated. A natural method of control is to colonize your garden with ladybugs, which will feed and control the aphids. Manually removing the pests or using a fungicide spray are other options.
Snails and Slugs
Slugs and snails can damage your purple toadflax by creating ragged holes in its leaves. this inhibits the plant's overall health, affecting growth and making it vulnerable to secondary infections. Placing a copper wire or a Diatomaceous earth solution around your plants will act as a repellent against these gastropod pests. Beer traps also work very well.
Other Uncommon Pests or Diseases
Moreover, there are some less common pests and diseases listed below that need your attention:
- Weevils (Gymnetron antirrhini, Mecinus janthinus)
- Moths (Calophasia lunula)