Hypericum is a very disease resistant plant and generally suffers from few hypericum diseases.
Root and Stem Rot
Occasionally there are outbreaks of root and stem rot. The major problem with this fungal infection is that there are few signs that anything is wrong until the plant dies. There might be a little fading of the foliage and in some cases it could turn yellow. When a dead plant is inspected you will observe that the roots have fine white fibers growing on them and many roots will have died. This disease is located in the soil.
This is another fungal disease that affects hypericum occasionally. The symptoms are fairly obvious although the plant does not often show signs of stress. The stems and leaves have white fibrous growths on them and the stems can some times start to die back.
This fungal infection causes brownish spots or stains on the leaves. The spots aren’t clearly defined and can spread and look more like a blight than a simple spotting fungus.
Leaf Blight and Stem Die Back
Leaf blight affects the lower leaves of the plant and is often barely noticeable. It is more of a discoloration of the leaves. The stems die back quite rapidly but the plant cannot be saved once that starts. It seems strange that a plant with so many medicinal uses should have these problems. As with all fungal problems many of the outbreaks of the diseases can be prevented by better husbandry.
The condition of the soil is the one thing that impacts most on plant health. If the nutrients aren’t in the soil to keep the plants robust and healthy they will be vulnerable to fungus diseases. If the soil is allowed to become too moist or even wet the likelihood of a fungus infection is very high indeed. Plant roots need access to air if they are to remain healthy but the water drives the air out of the soil and the roots can smother.
After the soil the level of ventilation becomes important. With no breeze around the plant it cannot transpire successfully and can become waterlogged. The still air will also make it far simpler for mold spores to settle onto plants and germinate. Continued stillness will mean that the spores will mature, produce fruiting heads and release another load of spores into the air and re-infect the plants.
When a fungal infection really takes hold in a population of plants it is often necessary to destroy diseased plants to reduce the possibilities of re-infection. To prevent the situation arising again there will also have to be a culling of the plants to ensure that the ventilation of the plants is improved.
Root and Stem rot is a soil borne disease and will attack any plant. Usually the attack is precipitated by a weakness in the plant. Where there have been outbreaks of root and stem rot it is often necessary to treat the soil with heavy doses of antifungal treatments. The application of plenty of compost to the soil can often release helpful microbes into the soil that will seek out and kill this type of spore.