Using Science to Enrich Beautiful Landscapes
Junipers can be specimens when sheared and cared for properly. Resorts are famous for using these plants to shape into interesting displays for quests. Two diseases that affect them are Rust and Phomopsis. Rust disease
WHAT YOU’LL SEE…is that the new growth of your shrubs has begun to die back. While this is called Juniper Twig Blight, it may also affect other plants such as arborvitae, yews, firs and cedars. There are other reasons for tip die back which must be ruled out (winter damage, wind burn, etc.) but this is a very common problem on Juniper hedges in the landscape. Juniper Rust forms along the branch stems and globs of jelly-like orange substances form on the needles.
THE REASON FOR THE PROBLEM… Over-watering is the reason for Juniper Twig Blight. Hot summer temperatures combined with high humidity is what causes a fungus called Phomopsis sp. to infect the foliage. The fungus survives the winter in older infected wood in the plant and then in the spring rears up to begin new growth. Moderate weather (55-80 degrees) with rain will favor development of the fungus. A prolonged wet spring will really encourage this disease to run out of control.
THE BEST WAYS TO CONTROL THIS PROBLEM…is to prune out the damaged branches in dry conditions only. Recall that rain, or irrigation water, is what spreads the fungus. Only prune when the plant is dry to minimize this problem. Correct pruning techniques are important also to encourage healthy growth. Proper fertilization is important to maintain plant health and vigor. Fungicides should be applied specifically when activity is about to occur. This may require a professional service and one in which we can be of assistance.
Posted on: August 4, 2015
What you’ll see…is wilting leaves and dieback of branches, often one at a time or on one side of the tree. This can occur over a number of years, with remiss...