Italian Cypress Snapping Off in Wind Might be Borers

Q. Because of the wind the other night the tops of two Italian Cypress trees broke off about 11 feet off the ground. Do you think this was caused by lack of water?
We have 18 of these trees by the back fence. We planted them in 2005 and we have been watering them for nine minutes, three times a day, six days a week in summer.

            As they grew I didn't increase the watered until about 3 years ago when I found out they needed more water. So now I use a hose and water each one about 15 minutes every 3 weeks in Summer.  I'm hoping you can see by the picture, there seems to be a growth around the area where it broke off.  Do you think this was caused by lack of water?

Italian cypress with possible borer damage. Borer weakened the limb and it snapped easily.

A. I can see the picture quite well, thank you. I don’t need to know the watering schedule or amounts. Other people have told me that they think they had borers in Italian cypress. I had never seen borer damage in Italian cypress in my 30 years in Las Vegas.

            Well, I think you have it. This growth you are pointing out in the picture, I think is growth we typically see AFTER borer damage has occurred. Borers don’t typically kill a plant overnight, or even in one season, unless the plant is very young and the damage is extensive. Usually plant decline from borer damage can take several years.

            Plants can survive and look like nothing is wrong for several years during annual borer attacks. Having borer damage depends on a lot of things; how healthy the plant is, how fast it begins recovery after the attack, how heavily it was attacked, etc.

            In short, it is possible that your plants were more susceptible to borer attacks because of a lack of water during the summer.

            There is a product for borer control but it would have to be applied once, annually, to protect the trees. It is a good product and you can find it at your local nursery.

            In the meantime, if the disproportionate sizes bother you I would go ahead and lower them all so they are the same height. They should do just fine if they are pruned all the same way and I don’t think it will be very noticeable after a season of growth.

25 year old Italian cypress with the top removed