Brown tips on leland cypress and other evergreens
I have two beautiful, mature (30 ft +) leyland cypresses in my yard. Very recently, I noticed that their tips are turning brown in spots. I do not recall this happening in previous years. I see the same phenomenon on my neighbors evergreens (I think they are thujas) that border my yard. See attached photos. Is this a disease? Do the trees need to be treated?
The tree in the left photos looks like a leyland cypress. The brown tips on the branches looks like seridium canker, a fungal disease. When these trees are stressed due to drought, poor planting techniques, poor drainage, etc. they can be susceptible to disease and insect issues. If planted close together there is a lot of root competition for moisture and nutrients, lack of sunlight, and poor air circulation.
Look at our website for photos and more information. There is no control for seridium canker. The brown tips will drop off naturally. Prune any dead branches during dry weather. The best recommendation is to keep the trees well watered during dry periods. Keep mulch no thicker than several inches and away from the base of the trunk. The trees grow best in full sun with plenty of air circulation and appreciate moisture during dry periods.
Right photo - We cannot tell from the photo if the tree is a type of juniper or a Boulevard chamaecyparis. Browning can be due to
several factors such as lack of sunlight, poor drainage, drought, root competition for moisture and nutrients, etc.
In general, one of the characteristics of the Boulevard Chamaecyparis is that the old inner needles die and do not fall off. Consequently, there is a lot of unsightly dead material on the tree, making it undesirable. There is nothing you can do to remedy this problem.
You will have to decide if you want to prune the dead plant material or replace the juniper or chamaecyparis. There is no chemical control. This may be an opportunity to allow more sun and air circulation for the site.
We also notice English ivy growing up the trunks of the leyland cypress. This vine is invasive and can deny photosynthesis when growing up into the tree branches and canopy. Cut it off at the base of the tree and paint the newly cut end of the vine with a systemic herbicide (one with the ingredient glyphosate or triclopyr) at a high strength. Do not let the herbicide get on the tree. Also, to make it easier to see what has been removed, cut the vine off again at about shoulder height so that you can easily see a bare area about the tree base. Do not let new tendrils start going up the tree again. Keep it off. You can also physically pull up or dig up the root of the vines on the ground.