I have a purple leaved cotinus (smoke bush) that's about 5/6 years old. early every year in late summer the leaves on random stems start to wilt and die while the remainder of the bush stays healthy. When it first started happening it was following wet weather so I thought the problem was caused or exaggerated by the wet, but it has happened this year and the summer has been dry, so wet cannot be a big factor.
The shrub seems to go dormant normally, is usually lightly pruned in spring and grows again fine. It is a real mystery. The shrub is planted in a sunny spot, the soil is chalky loam. Site is a mixed border alongside a hedge and with other shrubs close by but not right next door to it.
Anyone got any ideas? Thanks.
I've been waiting for somebody who knows to answer this. But if you want my input, we coppice ours every 3 years to keep it neat and to stop it getting leggy as the leaves do seem to drop from the lower end of the branches. I have noticed it only 'smokes' on old wood, which is why we don't prune every year, but prefer to coppice every 3 leaving the best of the old wood for next years flowers (smoke). The plant is related to that horrible stags horn thing that gets really leggy, so I suppose loosing the lower leaves is in it's genes.
Thanks for the reply ACE. Unfortunately thats not really the problem. I generaly do coppice or at least shorten the stems to keep it neat every spring. Last time it needed it, as last summer it became really wayward and leggy. This year it has grown nice and upright and looked really good - until the dieback problem reoccured. And i guess it is dieback not natural leaf loss like you suggest. The dieing off of leaves starts at the shoot tips and works down wards, first looking like wilting then goind brown and ugly (not like the nice red the leaves turn in autumn at all). Since posting i have gotten sick of looking at the brown leaves and cut the stems affected off and binned them. Unfortunately i now realise this might not help[ find out the cause of the problem!!
I dont have recent photos of the problem but as this has reoccured again and again i dug out a couple of photos i took of the cotinus in aug 2010
http://img.photobucket.com/albums/v159/richardfiler/General/DSCF4708.jpg
Whole shrub view
http://img.photobucket.com/albums/v159/richardfiler/General/DSCF4709.jpg
close up of branch.
Hope this helps explains things. Thanks
I had to google this one as it looked like wind burn, which it isn't but check out verticillium wilt, I hope it is not your problem as it looks like it is not really treatable. But a weak mix of armillatox like you would use for honey fungus might help.
You just beat me to it Ace,I did. 'Google' too and found this;
http://apps.rhs.org.uk/plantselector/plant?plantid=559 (http://apps.rhs.org.uk/plantselector/plant?plantid=559)
Quote from: ACE on October 04, 2013, 18:21:47
I had to google this one as it looked like wind burn, which it isn't but check out verticillium wilt, I hope it is not your problem as it looks like it is not really treatable. But a weak mix of armillatox like you would use for honey fungus might help.
I have done some research about verticillum wilt and sadly it seems most if not all the symptoms fit the MO of the disease. I havent been able to look at any stems to see if they show any signs of the black ring in the cambium layer, which would prove it beyond doubt. The fact that only half the shrub is affected sems to be another characteristic.
Thinking back i have had problems growing things in that part of the garden, plants put there before have struggled for no apparent reason. Often wondered about 'bad soil' but when i planted the cotinus and it seemed to take, i thought i had just picked the wrong plants before.
Not sure what to do, the shrub is still OK despite the disease and with the affected stems removed still looks good, so I am reluctant at this stage to remove it - which itself is risky as there is the chance of spreading the disease to other parts of the garden if the soil is disturbed. Thankfully it does appear to be contained in one small part of the garden and no other plants even close by are showing signs of the same affliction.
I thought perhaps in the short term some TLC for the cotinus would be a good idea i.e. feeding and mulching (in spring?) so helping the plant to fight the disease and keep it going for a while longer.
Thanks for pointing me it the right(?) direction
Oh dear - this does sound like verticillium wilt (and cotinus is notoriously susceptible). Am going through the same heartbreaking scenario with a 10year old cercis, Forest Pansy. Naturally, I was in denial for a couple of years but this year, the spade is coming out as I cannot face the protracted (but inevitable) demise.