Gardening Question From Lynn:

We are in Culver City,Ca and have three one year old Tabebuias all of which are developing black/brown tips of leaves as well as black spots. Could this be a drainage issue, and/or over watering or part of the semi deciduous process? Our arborist suggests over watering. Any tips on how to move forward with these lovely trees to prevent losing them. P.S The staff at Armstrongs in West Chester Los Angeles swear by your expertise. Thanks very much.

Photo by mauroguanandi

Answer From Pat:

First, there may be nothing wrong with your tabebuiias. On the other hand, brown or black tips sound like wind damage or salts in the soil. If your soil is clay, I suggest topping the soil once or twice with soluble gypsum and watering it in. Apply gypsum annually and this will help wash away the salts. Black spots on leaves sound like black spot fungus, which can come from moist, damp weather. Several organic sprays are made for controlling black spot fungus, but you can make a homemade spray with one heaping tablespoon of baking soda and 1 teaspoon horticultural oil to a gallon of water. Shake well and spray in the evening or early morning. Also get rid of plant debris where this fungus might be proliferating.

I hope your trees are not growing in partial shade. They need full sun and good air circulation.

Thank you for the compliment from Armstrong’s Nursery in West Chester. I am a frequent customer at the Armstrong’s nursery near my home.

Photo by mauroguanandi