Black knot, petal blight answers
By Darrell Blackwelder
For the Salisbury Post
SALISBURY — The weather is always a relevant topic concerning gardening, especially with unusual weather experienced over the past few weeks.
With unusual weather comes myriad gardening questions, some of which have no relationship to the weather. But some people believe the weather may be the culprit in their gardening woes. Below are a few gardening questions received earlier this week that may be of interest.
Q: My mimosa tree is six years old and it has died for no apparent reason. Could the cold weather earlier this year have caused the tree to fail?
A: Mimosa trees have a serious problem with a soil borne fungal disease called Fusarium wilt. It is a similar fungus that infects tomatoes and peppers. When trees reach a certain age, usually between 6-12 years old, they succumb to the disease. Most native mimosas never live more than 25 years. There is no feasible control for the disease.
Q: I planted a damson plum in my small orchard and it was doing well until this year. Now it has black growths all over the tree. What are these growths and how do I control this?
A: Your tree has developed black knot. It is a fungal disease that gets on many of the trees in the Prunus sp. family including plums and cherries. In the fall and winter, prune out all infested limbs and twigs and burn or bury them. These trees need to be sprayed early in the season with fungicides to prevent spread of this fungus.
Q: My camellia has a problem with its leaves. Some are big and rubbery. What is this? Will it kill the shrub?
A: Petal blight is a problem not only with camellias, but also with azaleas and other plants. The distortion is caused by a fungus fueled by cool weather and high humidity. There is no logical control. Infested leaves will fall off and the plant will recover.
Q: I’ve been working outside in my yard and I think I may have gotten infected with poison oak. Is poison oak and ivy leafed out yet? How can I control it?
A: Poison oak is starting to leaf out now, but the sap from a deciduous vine is still potent. Be careful when you cut stems and vines. Roundup (glyphosate) or a brush killer will eliminate the noxious weed.
Darrell Blackwelder is the County Extension Director with horticulture responsibilities with the North Carolina Cooperative Extension Service in Rowan County. Learn more about Cooperative Extension events and activities by calling 704-216-8970 or online at www. rowanextension.com.