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Clematis is one of the most popular climbing plants thanks to its colorful flowers, which are often the size of a plate. If there weren't so many leaf diseases on your clematis that make life difficult for plants and hobby gardeners.
In a nutshell
- Clematis, or clematis, is susceptible to various diseases caused by fungi
- probably the most feared fungal disease is clematis wilt
- two forms of clematis wilt: Phoma and Fusarium clematis wilt
- Wild species and large-flowered hybrids are rarely affected
- other leaf diseases are powdery mildew, gray mold and bud rot and iron deficiency chlorosis
Clematis wilt
Clematis wilt is actually two leaf diseases on clematis with different courses, phoma and fusarium clematis wilt.
Phoma clematis wilt
causes and symptoms
- the most common form of clematis wilt
- caused by fungal pathogens called Ascochyta clematidina
- Fungus penetrates the plant through small injuries
- in spring small light brown leaf spots with a yellow halo
- Infestation begins in the lower third
- first on the undersides of older leaves
- Spots get bigger and darker
- entire sheet is destroyed
- later the shoots wither
- Spread favored by warm, humid weather
Notice: All types of clematis can be affected by this foliar disease, but only the large-flowered hybrids die off completely above ground.
combat
- Combat only promising in the early stages
- as long as the shoots are not affected
- completely remove affected leaves
- dispose of in household waste
- also consistently remove leaves lying on the ground
- If necessary, shorten the shoot tips a little
- Monitor infestation carefully
- if leaf disease progresses, cut back to ground level
- fungicides can be used after cutting
Tip: If the affected plants are wild species, Phoma wilt is usually limited to the leaves. It turns out to be more harmless then.
Fusarium wilt (Fusarium oxysporum)
causes and symptoms
- far less common than Phoma clematis wilt
- Infestation only at temperatures between 20 and 30 degrees
- around the second half of June
- Leaves turn brown from the edge
- Discoloration then spreads to the middle of the sheet
- Leaves and shoots hang limp above the infestation
- look dried up
- Plant dies down to the roots within a short time
- only parts of the plant above ground are damaged
- Roots are not infected
- can sprout again next year
combat
- infected plants can usually be saved
- Be sure to remove affected parts of the plant
- Prune the plant back to healthy wood
- possibly also close to the ground
- Dispose of clippings in household waste
- Fungicides ineffective against Fusarium wilt
- then thoroughly disinfect the cutting tools used
Prevent clematis wilt
A climbing aid can help prevent leaf diseases on the clematis.
- Planting on loose, deep soil
- choose a rain-protected, well-ventilated location
- Regular control of the plants from May
- do not pour over leaves and shoots
- Water and fertilize as needed
- Regularly remove weeds in the root area
- Avoid damaging the plants
- stabilize with bars or supports
- look out for resistant varieties when buying
iron deficiency chlorosis
This leaf disease is a deficiency disease of clematis, in this case iron deficiency. Diseased plants suffer from a disruption in their photosynthetic metabolism.
causes and symptoms
- common cause too high lime content in the soil
- caused by calcareous irrigation water
- due to heavy soils with a high lime content
- or by alkaline, particularly light and dry soils
- other causes are long periods of cold, low light intensity and drought
- first signs are discoloration of young shoots and leaves
- lose their color and become paler
- from light green to light yellow
- quickly spreads to older leaves
- Leaf veins initially remain green
- Leaf edges are drying up more and more
Tip: Iron-deficiency chlorosis can promote gray mold infestation in clematis.
Iron deficiency chlorosis on the clematis can be recognized by the discolored leaves.
control and prevention
- remove affected leaves
- Apply fertilizer with the missing nutrients
- foliar fertilization recommended if necessary
- Nutrients can be absorbed directly
- Incorporate peat into the soil
- completely replace the substrate for potted or tub plants
- It is best to boil tap water as a preventive measure
- Improve the soil in the long term, pay attention to the correct pH value
Notice: You should never use chelated iron for foliar fertilizers, as this could cause lasting damage to the leaves. Special foliar fertilizers from specialist shops are better.
gray mold
This leaf disease on clematis is also transmitted by a fungus that overwinters on dead plant tissue. Wind and water spray can keep spores aloft throughout the growing season.
causes and symptoms
- leaf disease also known as chlorosis or botrytis
- mainly occurs when potted plants are overwintered frost-free
- especially in the greenhouse or conservatory
- damp, cool and stagnant air is responsible
- specimens cultivated outdoors less frequently affected
- Gray mold leaves a greyish, often dusty carpet
- first on leaves and flowers
- then spreads throughout the plant
- Flowers do not open, those that have already opened are stuck together and fall off
- dark brown rotten spots on young and soft leaves and shoots
combat
- usually no countermeasures required outdoors
- otherwise cut off all affected parts of the plant
- Treat plants with easy-to-make horsetail broth
- from ten liters of water and one kilogram of horsetail
- Soak the cabbage in water for 24 hours
- then bring to the boil and simmer gently for about 30 minutes
- strain after cooling
- Spray infested plants once or twice a day
- over a period of four to five days
- then ensure good ventilation
- In extreme cases, treat with sulphur-containing preparations
prevention
- keep a sufficient distance to other plants
- avoid damp and poorly lit locations
- Leaves should dry off quickly after rain
- water moderately and fertilize
- Do not wet leaves and flowers with irrigation water
- ideally water in the morning
- Avoid over-fertilization, especially with nitrogen
- Plants with plant broths z. B. Strengthen field horsetail
mildew
Powdery mildew is a common fungal disease. When infested with this foliar disease, the fungi draw nutrients from the clematis. This not only results in visual impairments.
causes and symptoms
- mainly in wet, cool and dry, muggy and warm weather
- favored by temperatures above 20 degrees
- Plants in dry, poorly ventilated locations are particularly at risk
- large-flowered hybrids more commonly affected
- mealy-white coating on the upper side of the leaves
- also reddish and brownish spots on the leaves
- as a result, the leaves dry up
combat
- Treat infestation as early as possible
- proven remedy for initial infestation is milk
- mix 900 ml water with 100 ml fresh milk
- Spray the upper and lower sides of the leaves with it
- Microorganisms in the milk fight the fungus
- Repeat treatment about every three days
- UHT milk is unsuitable, contains hardly any microorganisms
- against heavier infestations, use biological sprays based on sulfur or copper
Tip: An effective alternative to milk is whey. Or you can use a spray solution made from a liter of water, a tablespoon of rapeseed oil and a packet of baking soda. With these solutions, some leaf diseases on clematis can be combated.
prevention
- ensure sufficient planting distances and good ventilation
- Water as needed, mulch soil
- Sources of infection such as B. Minimize weeds
- prefer hardy plants
- attract natural predators such as ladybugs into the garden
frequently asked Questions
Are there varieties that are attacked particularly often?Large-flowered hybrid varieties and hybrid varieties that bloom on old wood are particularly affected by clematis wilt. Numerous wild species and hybrid varieties flowering on this year's wood (Jackmanii group) are far more robust. Some perennial clematis as well as the 'texensis', 'viticella' and 'recta' clematis are particularly susceptible to powdery mildew.
Can clematis suffer from soil fatigue?Soil fatigue, as is known from roses, for example, does not usually occur with clematis. However, if the plant has died of a wilt disease, a generous soil replacement is recommended.
Which planting distances can help to avoid diseases?The planting distances depend on the respective variety. In the case of the alpine clematis 'Clematis alpina', this is 50-80 cm, for the Italian 'Clematis viticella' 60-100 cm, the mountain clematis 'Clematis montana' requires 100-150 cm and for the common clematis 'Clematis vitalba' distances of 200 -400cm recommended.