Ground Work: Fresh water preserves Christmas tree

Are there any products on the market to prolong the life of a freshly cut Christmas tree?

Clean water is best. When you get home with your tree, cut an inch off of the base and immediately put it in water. The tree should go in a stand that holds at least one gallon of water.

Plain water, without sugar or fertilizer, is best for the tree. Make sure to check the water supply for the tree, especially when you’ve just gotten it because the first couple of days the tree will go through a lot of water.

Our holly trees have black on the upper surface of the leaves and on the berries.

If you are able to wipe the black coating from the leaf, then sooty mold is the symptom. Its presence is caused by insect feeding activity, likely scale insects.

Treat the plant for scale and there will be no new sooty mold. With moderate temperatures you can apply a horticultural oil several times (2-3) to help kill scale and to assist with sooty mold removal.

A soil drench using (imidacloprid) will prevent scale next year if applied in spring.

The insects may be feeding on foliage above the holly and honeydew is dropping onto the holly foliage and berries resulting in black leaves.

I was hoping you might be able help me find some information about the proper way to prune an avocado tree. I have a 7-foot-tall potted tree that I started from a pit in water. The main trunk is very spindly. Would pruning make the trunk stronger?

The reason the avocado is spindly is due to poor indoor light quality. Pruning the trunk probably will not result in branching.

Placing the tree outside next year and allowing it to move with breezes will help increase trunk diameter.

Place in full, direct sunlight. This will likely scorch the existing growth but new leaves will regrow. I’d suggest planting a few seeds in one pot for a multitrunk specimen and grow in better light indoors.

Got a gardening question? Write to Bob Souvestre, horticulturist with the LSU AgCenter, at Burden Center, 4560 Essen Lane, Baton Rouge, LA 70809, or email to, or call Master Gardeners at (225) 763-3990.