Cheryl, I'm seeing a lot of suckers in a new bed where I've dug up some grass a few feet from a giant 100-yr old CM. I thought I pulled out all of the roots during the digging, but obviously not. A few times a week, I see a new little clump of CM foliage poking up somewhere. They pull up really easily, but IDK how long this will go on.
Also extremely interesting is that some of the smaller pieces of roots that got thrown in with the dug-up grass didn't die. They're not decomposing, they're growing new foliage. Need to make sure this stuff is shriveled before attempting to compost. So glad that was the plan for the chunks of grass anyway, or I could have inadvertently "planted" CM in other spots.
The disruption to the roots also seems to have spurred a much stronger flush (than usual, previous years) of suckers throughout the lawn, and around its' base. There's no hope of ever rehabilitating its' giant stump-base into anything looking like a normal tree. It's been pollarded most years for its' whole life. So, it will always be making suckers. I'd planned to get rid of all of the grass around it, but SOOOO glad I didn't do it all at once. Now I realize, that's a horrible spot for a garden, unless I want to battle CM suckers every year.
They're reliably hardy but deciduous here. Most specimens spend half of the year looking like really short telephone poles, and always surrounded by tons of suckers. Other specimens that have never been pollarded (only maintained for shape, as one would do with any tree,) make few, if any, suckers. Exactly the same patterns as Syringa (lilacs,) except that lilacs are pruned into hedges/clumps instead of being pollarded, when not left to their own devices, to form the beautiful trees that they can be.