Mine are greening up now in about zone 6andahalf - somewhat slower, perhaps, than the large-flowered clems. Don't worry. This is a very hard vine to kill and very cold hardy.

I'm zone 5/6 and mine has been leafed out for a couple of weeks.

Did you cut back in the fall or spring? They should NOT be cut back in the fall, and that could have really set it back.

Mine is vining away right now ! It came with the house as an established plant. I butcher this thing each year and it is unstoppable. Unfortunately for me, it re-seeds everywhere and I then have tons of baby sweet autumns to pull all summer. I did transplant one to climb a fence last year, and it is also leafed out and climbing everywhere now. That should look nice on the bare fence this year. I have found that they bloom on new wood, so I chop it to the ground each winter, then it re-grows each year and flowers for me in Sept. It is such a vigorous grower I sometimes have to prune the sides to keep it somewhat on the trellis and contained, or it will grow on/smother your other nearby plants. Have faith in yours, it will awaken soon !!

My two Sweet Autumns have just barely started to leaf out, many of my other clems are much furhter along.

All my Clematis is starting slow. I have already cut back the Sweet Autumn vines to about 3ft high. I do a spring trim on that so the vine provides winter cover for the birds. I think the green leaves help feed the roots over winter, so fall trimming would take away food. SA comes back very well, covering an arbor and a large section of privacy fencing by fall. Blooms beautifully.

The leaves on these two Sweet Autumn are rather heart-shaped, and the flowers are lovely with great fragrance.

I say this because I have had other vines labeled Sweet Autumn Clematis that had different shaped leaves. They were the 3-lobed type like Tauntigua Clematis. They did reseed and sprout heavily, along with poor flower show and stinky flowers!! I pulled it out last year and have been hunting out the sprouts to prevent more growing. Flower shapes were very similar, but the smell was awful, and reseeding sprouts were NUMEROUS!

I let that vine go 3 years, before I caught on to the differences that were more visible with age on the plant. I had heard of others folks disliking their SA clematis, could not understand why until I figured out there were two kinds being marketed. The heart shaped leaf plant is very good at length of vine, but I have had not much reseeding problems. The Arbor is totally covered in flowers when it blooms, and they last for quite a while, replaced by the attractive poofs of seedheads.

Your slower leaf appearance is probably just due to cold temps and not enough sunlight yet. They will come along shortly.

Leaf? I cut mine back last week to about 1 foot but I have nothing green at all coming from anywhere. But we're only in April and most things are still only an inch tall yet.

Plus it's still pretty shaded from the sun - I was just worried as I have seen no shoots and this is the first spring with a Sweet Autumn Clematis so I don't know what to expect.

AND - only my 3rd year of being a gardener.

You can see my results here if you feel like seeing a newbies attempts to be a gardener.

Here is a link that might be useful: My Lasagna Gardens