Wednesday, May 13, 2015

Junipers turning brown.

Q. I have a lot of juniper ground cover and have a problem of them turning brown after having been in ground for 2 plus years. What can I do? 

A. You need to know the source of the problem before you can remedy it. Here are a few things to consider.

First, your Juniperus species might not be getting enough water. While it's true that junipers are generally drought-tolerant, gardeners often rely too much on drought tolerance, and neglect watering when necessary. There is a point of no return. If junipers show drought stress by exhibiting dull, dry foliage, it's already too late to save them. By the way, the same is true of most conifers.

Second, your junipers might be suffering from a pest infestation. Mite and bagworm populations can easily increase to the point that they kill host plants. Miticides (also known as acaricides) might be effective. Follow label instructions. The best way I've found to control bagworms is to identify the bag-like cocoons early on, remove and destroy them. The cocoons are easy to overlook. They're covered with brown twigs and resemble small pine cones.

Third, your junipers might be afflicted with a type of canker. These diseases are caused by fungi that enter plants through wounds. Affected plants are often already under stress for other reasons. Dying branch tips and weeping wounds are notable symptoms. Fungicides are seldom effective. The best course of treatment is to remove the diseased plant portions. If the disease is advanced, remove the plants and replace them with another species not affected by canker. Fungal spores will continue to be present in the soil.

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