Gardening with Gary

Gardening Advice from an Expert

Palm Plants

Matt writes~ I have an indoor palm plant and the leaves are getting all sticky. I think it is sap. Why is this happening?

A. There are two possibilities I will suggest.

One is that it is quite normal for palms and many other indoor house plants to 'bleed' a liquid from their foliage. This is during the process of transpiration where the water is secreted many times due to high temperatures or humidity. It is very similar to our perspiration. There is absolutely nothing wrong with this, it is natural and unavoidable. The liquid sometimes picks up other materials in the leaves which make it sticky.

Second, a widespread presence of sap or sticky liquid on the foliage of plants, many times undersides, too, can be the result of aphids. They secrete the liquid in the reproduction process. You may notice a black growth on some of it. That is an opportunistic fungus which is growing on the sap and feeding on it.

Look for green bodies, very soft and slow moving. These will need to be sprayed with a house plant insecticide like Schultz or an organic one as Safer's Insecticidal Soap, both available at nurseries, hardware, drug stores and garden centers.

You will need to take a close look at the palm and decide which is the more likely occurrence.