By Lois Scott, Master Gardener
Garden gazing out the window a couple of weeks ago I noticed, with a sickening jolt, that my Clematis x jouiniana ‘Mrs. Robert Brydon’ was wilting. (It’s only a plant, Lois, only a plant). She has been in my garden for 4 years and had been growing very well up to this point but it appeared she must have clematis wilt. Clematis wilt and clematis slime flux are the two diseases that this particular cultivar may be susceptible to. Not noticing any slimy, smelly matter oozing from the stems, I ruled out slime flux.
According to Missouri Botanical Garden, clematis wilt is a serious disease of clematis caused by the fungus Ascochyta clematidina. This fungus can survive in the soil surrounding infected plants and may overwinter in infected plant debris. The fungus appears to be activated by ‘high humidity and favourable growing conditions found early in summer’. Any to all stems may be affected and the whole plant killed down to just below soil level. The good news is that the plant may recover after a year or two.
There are ways to manage and avoid having your clematis plants affected by this disease and indeed other diseases of clematis. Strategies (cultural practices) include a favourable planting site with 6 or more hours of sun. Soil should be fertile and well-drained with good air circulation around the plant. The area around your clematis should be free of plant debris and avoid any injury to stem and roots. Do not cultivate the soil around your clematis plants and mulch it well. Water carefully, keeping water off the leaves. If your plant becomes infected, cut the diseased stems just below ground level and destroy them.
I removed and destroyed all the diseased growth on my clematis (which was all the growth) and there is now new growth coming up from the root. I will be paying attention to keeping leaf debris cleaned up, improving air circulation around the vine and watering as needed, with care.
Hopefully ‘Mrs. Robert Brydon’ will survive this setback. Her profuse, pale blue flowers are unusual and appealing to me. The gardener, Robert Brydon, who ‘found’ this clematis in a Cleveland, Ohio garden in 1935, clearly thought enough of it to name it after his wife! Sigh.