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Monday, September 12, 2011

Italian Cypress Browning Not a Good Sign


Italian cypress with foliage browning

Q. Help! My Italian cypress are drying out and dying mostly from the top down and they have their own bubblers for water.


A. Major reasons for Italian cypress dieback: Too much water. Water deeply once 3 - 4 weeks in winter and no more than about once a week in summer. Too little water. Sometimes people put these trees on just a few minutes of water from their drip irrigation system. Water should be applied so that it wets the soil down 24 inches to an area at least four feet in diameter around the tree. Depending on how quickly enough water from your drip system is applied this might take up to several hours of applied water.

Spider mites. Starts in hot weather because that’s what they like. Usually a problem on trees that were underwatered. Spider mites like dirty foliage. Wash trees with a high pressure hose nozzle after dust storms or a couple of times a year just to keep them clean. Periodic soap and water sprays are not a bad idea either.


Webbing in italian cypress may or may
not be due to the bad guys

Borers. Several people have reported borers in Italian cypress but this has never been a common occurrence in the past. I could not find it reported anywhere else either. Usually a soil-applied insecticide for borer control applied around the roots would be recommended if this were the case. Get your irrigation under control and that should solve most of the problems.

3 comments:

  1. I found that simply using a pressure nozzle on the end of a hose washes off the webs, which tend to be mite colonies. These little suckers suck the juice out of the tree fronds. It pays to wash down the cypresses about 4 times a year at least, to control the mites, and to wash out dead needles from the tree.

    The Italian cypress is very sensitive to insecticides, and may die off in areas where such is sprayed. One cannot apply enough neem oil or insecticidal soap to take care of the problem, so the water hose blast is still the best resort

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    Replies
    1. I used some "super safe" environmentally friendly pesticide on it and it did no harm to the plant, but I wish I'd thought of your hose idea, as brushing the material out was a pain. I brushed it first, then used the "safe" insecticide so it could get in better. Also used quite a lot, and it did work. Poor plant still looked so sad after all that, the owner wanted it gone. I will keep a close eye out for those buggies from now on and next time, they get the hose!

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  2. I just dug up a small cypress like this on the request of its owner because of such browning. It was infested with small, light brown caterpillars and their webbing and droppings. I did kill the bugs a few weeks ago and brushed out much of the damaged foliage, which resulted in a bald and ugly plant. I don't know if the bugs were secondary to another problem the plant had or if they were what was killing it. It never had looked really great in the past year I've been on this job. Its root system wasn't as developed as I'd expect, either. Maybe it was a bad place for it to be. Anyway, the plant was in Beaverton, Oregon. I should have taken a picture of the bugs but I knew I'd seen them before and assumed they were a common problem.

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