Like just about about other type of plant, you want to do this when the plant is dormant. So not now....better in late fall or very early spring before it buds out.

I rarely upsize my pots and have never found the need to do much in the way of root pruning with clems. I also rarely remove any soil from the rootball but prefer to keep it intact as much as possible. When I do upsize, I just add some soil at the bottom of the container, place the existing rootball in and fill with more soil.

Are sure the vine in question is a type 3? Those tend to be entirely be new wood bloomers and rarely bloom this early in the season...they are more the mid to late summer into fall flowering varieties. My type 3's don't even have buds showing now, let alone are flowering!! And they are usually continuous bloomers once they start, flowering until fall or cold weather sets in. No distinct flushes of bloom.

What you describe sounds more like a type 2, which would indeed have finished its first flower flush about now. But the repotting/soil refreshing advice remains the same.

Hi gardengal48, thanks much for the reply. Yes, it is a type 3 clem. I have only type 3 clematis plants, but each has quite a different he blooming peak time it seems. Princess Diana's first flush of blooms is almost coming to an end here, for example, but some others have just started showing some flower buds (and so some combos aren't blooming together lol... a mere thought of transplanting them is daunting).

Anyway, I'll follow your advice and wait until late fall, thank you. Just one thing I would like to have clarified -- you said you keep the rootball soil intact as much possible. In that case about what % of the potting soil is new and fresh after the job?

Thanks again!

I find your bloom time for these type 3's odd :-) Or maybe it's just my ingrained calendar of bloom times for my area!! But virtually ALL clematis authorities and references will state that type 3's are mid to late summer bloomers, and generally quote a bloom period of July through September. Having them already completed their bloom cycle now seems to me very premature. But I do realize that very southern locations may operate on a different timetable :-)

"Group 3 vines flower in late summer or in fall, on new growth produced earlier in the season." (Fine Gardening)

Re: the soil. If upsizing the container, it's about 50% new soil. If just replanting in the same size container, maybe only about 25%.

Thank you gardengal48! Funny, most of my clems (type 3s) have their first flush in mid June to early July, with just a few more yet to come, and you are in a warmer zone than I am (I'm in 7a, in the Mid-Atlantic). Defying authorities :-)

Again, thank you very much for the helpful comments!

Best,

Eri

My 3's are blooming in Portland.