The jade plant has thick, fleshy green leaves that grow on stems with the same characteristics. If allowed to grow tall, it will develop a thick trunk. In most cases, the jade plant is used as a house plant and is popular in bonsai. It produces small white flowers that grow in clusters and can reach a height of 3 feet.
The jade plant is very hardy. There are just two diseases that are prevalent in it. Oedema occurs when the roots of the plant absorb water fasten than the plant can use it and conditions make it hard for the water to evaporate through the leaves. The second disease is powdery mildew, common with many different plants. Indoor plants can contract it at any time of the year.
Odema is caused by long periods of cool and cloudy winter weather when the soil is moist and there is humidity in the air. The plant absorbs water from the soil, and the heavy humidity makes it hard for the excess water to evaporate from the leaves, causing water pressure to build up in the leaves. This disease is more common with house plants like the jade plant than it is with outdoor plants. Powdery mildew also thrives in high humidity. The fungus is airborne and can land on any plant.
Oedema produces small blisters on the lower pars of the the leaves. The blisters can harden into white, tan or brown wartlike bumps. Eventually, the leaves will become yellow and fall off. At this point, the plant will stop growing. Powdery mildew looks like dust on the plant, except that it begins as small white spots. The spots will grow until they cover the whole leaf. Powdery mildew can cause stunted growth and distorted leaves. The fungus removes nutrients from the plant causing the leaves to fall and the whole plant to decline in health.
Jade plants do not need a lot of water. They are succulents, used to living in the hot dry desert. Their leaves are designed to hold water for times of drought. Do not water until the soil is completely dry. Keep the humidity below 70 percent in the winter. Make sure the plant gets good air circulation. These should help the plant avoid both oedema and powdery mildew.
Plants that develop oedema usually recover when the weather improves in the spring. Powdery mildew can usually be rubbed off the leaves. There are fungicides that can he used to kill powdery mildew. Reduce the humidity, and pick up and dispose of all fallen debris so it cannot strike the same plant again or spread to others.