Chitalpa Leaf Drop and Leaf Browing

Q. This tree is approximately 15 years old. This house sat empty from 2004 until January 2020 when we purchased it. The house faces North and this tree receives full sun most days. Water during the 12 years was at best sporadic to none. I removed 95% of the plants and trees and just completed a comprehensive landscaping project. This tree was shaped and pruned by a licensed arborist. It suckers like crazy. It needs another round of sucker removal. I was not familiar with this specie and of course we moved in January and the tree had dropped all its leaves. The neighbors convinced me not to remove this tree because it was so beautiful in the summer, lots of flowers and beautiful leaves. I said yes because I did like the shape of it. What a mistake. The constant leaf and flower drop is terrible and a real challenge to pickup. In fact I made two mistakes, I planted another 24" box size from a local nursery . It is doing the same thing. I do not use my drip system and deep water the tree every 3 weeks during the summer months. I water from the trunk out 7 feet around the entire tree. I have a lot of large surface roots due to the lack of water. I am applying about 75-100 gallons per application. The leaves are full and supple, not dry and then boom they turn yellow, get this brown scalding and dry up and drop.

I have been researching and have not found a conclusive reason for this. The agricultural extension at NMSU wrote its not a matter of disease but rather a cultural practice. Soil may be to alkaline and getting to much water. According to Dr. Natalie Goldberg, NMSU Extension Plant Pathologists, "No plant pathogenic microorganism's were isolated from submitted samples. The symptoms occur on trees well watered as well as those that receive little water." The leaf drop starts when temperatures increase.

Can you bring me up to date with your latest information about this type of leaf drop. If I can't correct, both trees are headed for the cemetery.

A. I did print nearly everything this homeowner told me he did for this tree which was a lot. I abbreviated what he told me for the newspaper. It does not sound like a lack of water.

Older picture of Chitalpa in Las Vegas.

            Chitalpa is regarded as somewhat drought tolerant which means you should be able to water it less often than, let’s say, a purple leaf plum and still have it look good. It is not a desert species like mesquite or palo verde, but it can handle some lack of irrigation without dropping its leaves.

Limb dieback of Chitalpa from 2013.

            Unfortunately, all Chitalpa trees carry a vascular plugging disease unless propagated from seed. All the named varieties like ‘Pink Dawn’ were propagated from cuttings so they will be carrying this disease as well. You can’t see this disease outwardly but one of its symptoms can be leaf drop, starting particularly when temperatures get hotter.

            Unfortunately, Chitalpa infected with this disease is not a good thing to have around grapes or oleander either. The disease can be carried to either of these plants where it can kill several types of grapes like Thompson Seedless or it can stay hidden and spread from a bacterial reservoir that can be housed in oleander.

            The fact your tree has leaf drop in summer is suspicious. I would remove it. Replace it with a tree you like of a size in scale with your home. Single story home use a tree with mature height of around 20 ft. Two story home, look for a tree from 20 to 35 feet tall when mature. Smaller trees always use less water. Go to SNWA plant selector website to help you find one.