Is there any good reason not to prune Clematis jackmanii now? I know it is recommended to prune it, like other Group 3 clematis, in late winter and/or just before they resume growth in the spring because they bloom on current season's growth. Why wait until then? The vine always looks terrible over winter with dried leaves clinging to the vines so I'd really like to clean it up now.
@Margot good morning Margot, I find that if I prune Clematis jackmanii too early in the Autumn and we have a late warm spell that can so often happen these days, then new growth starts from where I really want it in the Spring. Then the harsh frosts hits the unprotected new growth and knocks it back. So I like the old wood to give it some protection and then cut it back to about a foot from the ground in late February to strong buds. Yes it can look untidy etc through the Winter but IMO it is necessary for the protection of the clematis. I don't grow jackmanii anymore, wrong colour scheme atm Lol. But it's a wonderful plant.
Thank you @Acerholic. Yes, I can understand the logic but wouldn't new growth occur no matter if the old vines are cut back or not? And, if some of that new growth occurs below where I'd cut (ie. lower 1 foot), the old vines wouldn't protect it regardless. Since harsh frosts are less a problem here now than formerly, I think I'll cut my clematis back this fall and wrap burlap around the bottom foot or so until temperatures begin to warm up again in late winter. I'll let you know what happens.
I think the burlap will do the trick in case of harsh frosts after cutting back. Just to mention I do not cut back any of my maples in Autumn however untidy they look as I don't want disease to enter and take hold over the Winter. Just a thought re Clematis as well. Look forward to seeing your lovely Clematis jackmanii blooms in 2021. Good night.