I grew Clematis virginiana from seed 2 years ago..they were planted in their permanent location last year. This year they really took off and are happily scrambling over an arbor and I see quite a few flower buds formed. We have acidic soil here, so perhaps yours doesn't like the additional alkalinity....

If you are fertilizing, STOP. If you must fertilize, use one with less N and more P&K, like tomato bloom fertilizer.

They are just coming into bloom on Manitoulin.

Thanks for the input. I haven't fertilized but I have added compost. I'll eliminate lime and see if that helps. Maybe patience is in order if they are just coming into flower on Manitoulin....Zone???? Any other suggestions are really welcome.

I'm in zone 6a and mine haven't bloomed yet this year. You can see the little white buds now, though.

Eatoncover or anyone else - are you growing your Clematis virginiana in moist soil conditions? I've read that they require a lot of moisture.

I started Clematis virginiana from seed this year. I have 6 seedlings happily growing in a large container. I have no idea yet where they are going to be planted - so I figured I'd pot them up and over-winter them in pots, then hopefully by next Spring plant them in a permanent location. Exactly what Ellen_S has done.

Ellen - what did you do with your seedlings the first winter? Although I overwinter many things in pots every winter, this is usually more mature plants and I'm worried about seedlings being more vulnerable to winter's assault.

My clematis is planted in compost enhanced heavy clay. The soil stays quite moist. I'd be interested in learning more about wintering over natives in large containers outside. Has anyone had experience with that in zone 5 or lower?

I overwinter stuff in pots every year. There always seems to be a "pot ghetto" hanging around. Last November, I bought 55 plants at a local nursery on sale for $3-5 each! Some were in small pots, but most were 1-3 gallon pots. Most of them were native perennials and grasses. No chance of something like warm season grasses growing and establishing roots that late in the season!

So I planted a few cool season grasses, then sunk most of them in the ground in their pots. I put some on the north side of the garage, surrounded by a heavy mulch of leaves and also bags of leaves. This is what I do with the pot ghetto every year. The idea is to insulate the plants from temperature extremes.

We had persistent snow cover all winter last year, which helped to protect all these plants in pots. I didn't lose anything but some Scabiosa columbaria 'Pink Myst' - which is not a native and is notorious for dying over the winter anyway, even when established in the ground.

Terrene - to answer your question, I overwintered my Clematis seedlings by planting them in my raised veggie bed, which I use as a nursery during winter. They all did fine and came up the following spring when I transplanted them to their permanent home.

They are just about to bloom for the first time and I am v. excited :-)