Hydrangea Diseases

Most types of hydrangeas are hardy and beautiful plants, but they are susceptible to a number of diseases that can dramatically reduce the plant’s growing potential. Many of the diseases that affect garden-grown hydrangeas can be treated, but if left untreated or unidentified, can prove to be fatal to the plant. Identifying and treating diseases quickly is essential to making sure a hydrangea survives a pest or disease.

Can Hydrangeas Survive Root Rot?

Root rot is one of the most untreatable types of diseases that affect all types of hydrangeas. It appears when the hydrangea is grown in standing water or exposed to too much water, as through flooding or over-watering. Hydrangeas affected by root rot will wilt beginning with the leaves and continue to wilt even when they are watered.

The only way to prevent root rot from spreading is to uproot and destroy the plant. Avoid root rot by ensuring that soil is well drained and irrigated to prevent standing water from affecting hydrangeas.

Powdery Mildew and Hydrangeas

Powdery mildew occurs in humid areas with high temperatures, and affects hydrangea plants that do not receive enough direct sunlight. Although hydrangeas can be grown in partial shade, plants that receive very little direct sunlight are more susceptible to this type of mildew. Shade and moisture allow mildew to flourish, and the mildew itself will cover the plant in a powdery substance.

This mildew is not especially harmful to the plant, but harmful strains can cause leaves and flowers to become discolored and eventually fall off of the hydrangea. Remove affected leaves and flowers, and treat the plant with a fungicide to treat powdery mildew.

What is Fungal Leaf Spot on Hydrangea?

Hydrangeas are also susceptible to disease as a result of too much direct sunlight in combination with high levels of moisture. This can create the potential for fungal leaf spots to grow on the hydrangea plant.

Fungal leaf spots appear when the climbing hydrangea receives too much direct sunlight. The fungal spots appear primarily on the leaves, which turn brown or gray and fall off; the plant itself can become sickly and die. This disease appears in mid to late summer.

Remove affected leaves from the plant and add nitrogen to the soil to help the plant continue growing. Avoid getting the leaves wet, as this can encourage the fungal growth.

Taking care of hydrangea plants will help to ensure that they are healthy, beautiful and continue growing for many seasons. Healthy hydrangeas are an excellent addition to any garden, and ensuring that they survive pest problems and disease is important.

Dedicated gardeners may also want to read up on Simple Garden Pest Control and Tips for Growing a Better Garden.