Clematis is a beautiful climber that produces many large flowers in spring and summer. There are clematis plants with double and single flowers, large-flowered hybrid varieties and wild species such as alpine clematis on the market. The plants are easy to care for and reliably bloom every year. Nevertheless, it can happen that yellow or brown leaves suddenly appear on the plants. Harmless care mistakes or a dangerous fungal disease can be to blame.
symptoms
If the first problems appear on the plant or even on several clematis, a more detailed investigation should take place. The following symptoms can occur together and each mark a cause:
- drooping leaves that are yellow or brown, very dry or wet soil
- yellowish, pale, drooping leaves, lack of growth, possibly green leaf veins
- light brown spots with a yellow halo in early summer, especially on older leaves
- all leaves of a shoot suddenly turn brown from the edge and wither
causes
Before the gardener gets too worried about his plants, he should first check the condition of the plants. Especially when the whole plant suddenly looks miserable, the leaves droop sadly and turn yellow, a care mistakes be the cause.
water supply
The soil in the root area is checked for dryness or wetness. Both a location that is too dry and waterlogging prevent the roots from transferring water and nutrients to the green parts of the plant. The plant dries up. If the site is too dry, vigorous watering is the most important measure. After that, the root area should be shaded. Mulch can be used for this or the area is planted with low plants. Clematis like it shady in the root area.
is waterlogging a possible cause, the plant is dug up. All rotten roots are removed and the clematis gets a new location with appropriate drainage to protect against too much moisture.
Clematis macropetala 'Rosy O'Grady''
fertilization
If the clematis lags behind in growth, the leaves take on a slightly yellowish color and perhaps even show green leaf veins, a lack of nutrients can be the cause. This can be a single nutrient or several. A soil sample provides information about which nutrient is missing. If you don't want to wait until the laboratory has examined the soil sample, adding a complete fertilizer to the plant can help. Compost soil with some rock flour also supplies the clematis with new nutrients.
Diseases
If care errors can be ruled out, it could possibly be one of the dreaded clematis diseases. These include Phoma wilt and Fusarium clematis wilt. The cause of both diseases are fungi, which spread throughout the plant and cause the above-ground shoots to die off.
Phoma wilt
This is the most common form of wilt on clematis. The fungus Ascochyta clematidina penetrates the plants through the older foliage. Light brown spots with a yellow halo appear on the leaves at the beginning of summer. These grow larger and darker until the entire leaf dies.
The fungus also spreads to the woody parts of the plant, infecting petioles, flower stalks and new shoots. The entire clematis is affected within a very short time. The fungus spreads rapidly, especially in warm, humid weather, and also affects neighboring clematis.
combat
In the early stages, it can be helpful to generously remove the affected shoots. All cutting material should be in household waste disposed of, but must be removed from the garden in any case. After that, the plant is treated with an antifungal agent. However, if the inside of the shoots is already affected, this no longer helps for sure. The plant can still die. If the clematis is infected over a large area, only a complete pruning close to the ground will help.
prevention
General prevention against diseases and pests:
- right choice of location
- Water and fertilize as needed
- regular visual inspection for leaf spots
- professional cut with disinfected tools
- Winter and rain protection
From around May you should check the clematis plant regularly. The first spots appear on the underside of the oldest leaves in the lower part of the clematis. Conspicuous shoots are disposed of immediately. Old leaves from the previous year should also be removed from the plant area.
A possible is also helpful dry location, either sheltered from rain by a canopy or with enough air movement to dry wet leaves quickly. Varieties that are particularly prone to being attacked by the fungus should be planted so deep that the first cm of the shoots are covered with soil. The fungus then does not penetrate so deeply and the plant sprout again.
Particularly susceptible varieties
In large-flowered hybrids, the entire aerial part of the clematis may die off. The early bloomers among the clematis are also susceptible. Although the disease can break out in other species, it does not get beyond individual, small leaf spots. The original varieties with small flowers have proven to be more resistant.
Clematis texensis 'Buckley'
Fusarium wilt
The fungus Coniothyrium clematidis-rectae is responsible for this form of clematis wilt. This disease is rarer than Phoma wilt, but more dangerous because it initially unnoticed runs. The fungus penetrates the plant through injuries to the wooden shoots and clogs the pathways there. The shoots then die off completely within a very short time. The fungus continues to spread throughout the plant, causing one shoot after another to wilt.
There are no spots on the foliage beforehand, so the dieback seems to start suddenly. The symptoms only begin when the temperatures are particularly high, which the fungus needs to grow.
combat
To at least save the plant, only one helps complete pruning, which should be done close to the ground. Fungicides from the garden trade are of no use against the fungus because it is inside the shoots. With a bit of luck, however, the clematis will sprout again next year.
prevention
Planting fast-growing, healthy varieties and a good supply of nutrients help against Fusarium wilt. Careful handling of the clematis protects against damage to the wood. You should only use disinfected tools for cutting. Winter protection prevents stress cracks caused by excessive solar radiation.
