Here's how to save your Euonymus
Q. I hope you can help me save my Euonymus. I have a bed of 14 Emerald and Gold euonymus very near the front entrance. They have developed growths (at least 12) that range from marble size to golf ball size. They are beige to rusty brown in color and have the rough bulbous look sort of like a cauliflower. What is this and how can I eliminate it or at least stop it from spreading? Most of the bushes look fine otherwise but some have started to thin so you can see into the center.
A. From your detailed helpful description it sounds as if your euonymus shrubs are infected with the soil-borne bacteria Agrobacterium tumefaciens that causes crown gall disease. This disease causes plants to weaken and branches to die.
The cauliflower-like growths you describe are galls that typically form on the lower stems, roots and crown of the plant. As the galls age they become brown, woody and roughened. Eventually the gall surfaces decay and slough off. Bacteria are released into the soil where they survive for two to three years.
The galls disrupt the flow of water and nutrients to the top of the plant. Plants with numerous galls become weak and growth is slowed. The leaves yellow and the branches may die back with eventual death of the plant.
Prevention and Treatment
The infected plants cannot be cured but they can be treated so they survive for several to many years. Prune out and destroy affected stems below the galled area. Disinfect your pruning shears between each cut by dipping it into rubbing alcohol solution or a 10% bleach solution.
Remove and destroy any severely infected shrubs. If you replace the shrub, select shrubs that are resistant to this disease such as boxwood, barberry or holly.
Q. Can hay be used as mulch?
A. Many times hay and straw are used interchangeably. However, they are not the same. Hay is an assortment of forage grasses that can include seeds of grasses and broadleaf weeds. Therefore, it is better suited for feeding livestock.
On the other hand, straw is a collection of the stems of field crops such as wheat and oats. After the seeds have been threshed, the dry husks are sold as straw. It rarely contains weed seeds. It makes a good winter mulch because the hollow stems hold air and act as insulation for the plants below.
Ÿ Provided by Mary Boldan, Mary Moisand and Donna Siemro, University of Illinois Extension Master Gardeners. Send questions to Ask a Master Gardener, c/o Friendship Park Conservatory, 395 W. Algonquin Road, Des Plaines, IL 60016, (847) 298-3502 or via e-mail to cookcountymg.com@gmail.com.