I have 4 Kwanzan cherry trees that are around 15 years old. they have had very little pruning other than the odd wayward or crossing branch, yet they sucker very heavily from the roots at the base of the tree.Any attempts at removal of the suckers has been met with vigorous regrowth.I am curious about cause and remedy.
The usual cause of this is when the surface roots get 'scalped' by a lawnmower or any digging that scrapes the bark accidentally. Once they start suckering, there is as you've found, no way of stopping it. 'Kanzan' Cherry (note correct spelling!) is usually grafted on Wild Cherry (Prunus avium) rootstock; the suckers will be of that.
Thank you for your reply.These were grown on "colt" rootstock.Tree and Shrub Gardening for B.C. and Taylor's Encyclopedia of Gardening both use Kwanzan, so you can fight that out with them.
I'd be interested to see a photo of these trees on the 'Colt' rootstock. There is a very nice 'Colt' tree in Vancouver that I'm pretty sure started life as a 'Kanzan'. I think I saw its last 'Kanzan' bud.
It appears that my spelling sources have been corrected.I will post a photo of my 'Kanzan' as soon as they bloom. They grow in a mixed shrub border with nothing but mulch,so unless I have inadvertently scuffed the above ground root surfaces while walking in the area,I don't know how else the roots could have sustained damage.On the other hand,if after the first sight of suckers were pruned,resulting in the ongoing sucker production,then I guess I have an annual task.As an added bonus I have a'Liquidambar' that has the same problem.