A question submitted by Margaret O'Dell via our Ask a Question page:
“My Rhus typhina is about 5 years old. Up until now it has been beautiful but this year it looks as if it's dying. Leaves shrivelled up before they came out and the suckers are coming up everywhere. HELP please... what should I do? Thanks, Margaret O'Dell”
Okay, we suspect this is a problem called Verticillium wilt and your photos show it graphically. Basically, the soil-
Alas there is no chemical control for this disease, however I’m sure the determination of your Rhus will mean a stronger replacement tree develops quickly. Do bear in mind, however, if the wilt has affected all the soil then it could strike again at anytime. If this seems likely, then remove as much of the Rhus root from the area and plant a tree which is known to be resistant to the disease.
The Royal Horticultural Society produces a list of resistant plants: Alnus (alder), Gleditsia (honey locust), Betula (birch), Ilex (holly), Carpinus (hornbeam), Liquidamber (sweet gum), Cercidiphyllum (katsura), Morus (mulberry), Crataegus (hawthorn), Platanus (plane), Eucalyptus (gum tree), Populus (poplar), Fagus (beech), Salix (willow), Ginkgo (maidenhair tree), Zelkova. Conifers are immune to the disease.
We hope this information helps.
To check to see if your plants are susceptible to Verticillium Wilt, please check this useful link: http://www.rhs.org.uk/Media/PDFs/Advice/Verticillium-