If it were me...and mind you I HAVEN'T see Kois' clematis yet..but I'd pot 'em up in one gallons for now and come spring put them in your larger pots...they'll have all fall and winter to grow some nice roots!!...Jeanne

Ditto to what Jeanne said. I would do the same!

OOPS. Violetta, just realized that you were planning on planting them in 18 inch pots and were asking about 1 gallons sized pots. Where is that EDIT button?? LOL If you are going to pot them in 18 inch pots anyway, I would go ahead and pot them up in them now versus the 1 gallon sized pots. I normally suggest potting up in one gallon sized pots when I have smaller plants that I want to grow out before planting them in the ground. The larger sized pot and soil mass will serve as insulation this winter, although in your zone, you probably won't need it.

If they have really tangled roots that go around and around as those did in a photo in another thread, I'd cut those off. They will not straighten out.

So the verdict is to plant them directly in 18" pots? Okay, I'm on it!

And yes, if the roots are as tangled as they were in the other photo I'll give 'em the chop.

Thanks everyone!