Jan, of the ones you ordered, clematis terniflora or sweet autumn clematis will probably be the most vigorous and will be impossible to kill once it is established. Gravetye Beauty is a texensis hybrid and more than likely be prone to mildew in our zone--it has been in my garden anyway. You may wish to start spraying with a system herbicide early in the season to prevent this condition which also strikes the following clematis in my garden: Etoile Rose, Princess Dianna, Pagoda, Roguchi, Arabella, and Viola.

Don't have any of the others but Marie Boisselot and Natascha are type IIs and my experience with type IIs in our zone is that in the heat of the summer, the leaves on the plant severely brown out. By early to mid July, when this starts to happen, I tend to cut my plants back severely and they resprout and reflower before fall.

Thanks for your response. I was planning on letting Gravetye Beauty ramble through my foundation shrubs rather than up a trellis. How have you used yours?

The sweet autumn will be allowed to take over the outside of my garden shed in the backyard, so aggressive is OK.

I have an unknown (two year old) clematis growing on my mailbox post currently. It looks like "Ramona" but bloomed for me only once in the late spring last year (unlike "Ramona" which should bloom in mid-to-late summer). It "browned out" as you describe, but not until early September. If needed, I'll prune my new vines down as you suggest and hope for a second flush of blooms.

As for mildew, I already treat my roses with a fungicide. I'll make sure to treat the clematis on the same schedule.

.....Jan

Jan, mine grow on what I called the Hershey Kissie obelisk because of the shape at the top along with Etoile Rose and Princess Diana--a very fitting trio since all three have serious mildew problems in my garden! They also tend to sprawl into the nearby beautyberry bush and anything else they can attach themselves to.

Jan - I just bought Natascha at a plant sale. What do you think of it? I was looking for something to followup my mystery white clematis which blooms at the end of May and early June. Does Natascha play well with others?

I've been really interested in sweet autumn, but I'm afraid it would be invasive here, like wisteria. Maybe you can let me know if a lot of seedlings spring up in a yr or two?
I'm sorry to hear that Arabella is prone to mildew- that was one I was really impressed w/. Can't help you about your choices but wish you the best of luck w/ them. Brandy

My Arabella has never mildewed and we had a bad year for mildew last year.

My Ramona blooms in late spring and never has rebloomed. I know it is Ramona.

Brandy, my SAC seeds terribly. It was a real problem the first few years I had it. Now to minimize the effect, I sheer the forming seedheads off after the sepals drop and I haven't had an issue with it.

SorB, my Arabella is planted next to Roguchi, a mildew magnet hence the Roguchi's problems become Arabella's problems possibly. Planted independently, you might not have a problem with mildew on Arabella.

So far, I have not had mildew on ANY Clematis. I have over 40 and some are close to 10 years old.

I did go on a real shopping spree last year so I haven't had over 40 all that time.

Crossing my fingers that I will continue to not get mildew on any of them.

Here's keeping my fingers crossed for you. I stopped counting when I hit 100 clematis and some of them are real mildew magnets. I personally think our hot humid summers have a lot to do with it. It was suggested once that moisture was the issue also but I keep the mildewy things watered well and that has never helped.