I've seen photos here of two different types of Clematis planted together and was wondering just how close together can they be planted?

Not so close that if one begins to act like it's on steroids it would make pruning difficult to impossible (as I have done). A foot apart is much, much too close. I'll be removing Vino eventually.

these two were planted in the same hole and have happily co existed for 10+ years
Of course I could just be lucky

They both appear to be the exact same pruning group/class...2. That won't give you problems but if you have a class 2 and a class 3 it will cause much more work when it's time to prune.

Ah, ok. Sounds like if they're the same pruning class, you can snug them together with no problem. My situation is that I have a mislabeled clem planted in a spot I had reserved for a specific variety. Off to look at which class each is. Thanks!

That was easy, and yea! Both the mislabeled one, Viticella Venosa Violacea, and the one I want for that spot, Florida Sieboldii, are the same pruning group...and would look very nice together, too! Think that will work, if they're planted very close (as in within 12 inches or even closer)?

Planted 12" apart is good. They'd each get the nourishment from the compost and manure in the planting hole and anything else you ever feed them with and they won't challenge each other for water.

Let us know how they work out as garden buddies and give them something to grow on or they'll scramble all over the gardens making working or planting more difficult.

Oh, I have a nice little trellis in place that was intended for the Florida Sieboldii. But what was supposed to be Florida turned out to be the VVV. Oops! So I was just hoping that I didn't need to dig up the poor thing (it's tiny, but it's blooming already!) after having it just get settled. Because it's in the only spot that might allow the Florida to survive in this zone, which is just a tad colder than what it wants.

Good!

Hope Florida Sieboldii works for you, I have heard it's is notorious for not being hardy in colder zones.

That's true, Sue. I've lost two and now lost the newest (and last) one but obviously this recent loss wasn't due to cold.

That's why I want it in this particular spot. It's against the side of the new addition to the house, on the southwest corner. Nothing ventured, nothing gained. If it croaks, it certainly won't be the first plant I've killed off! Now, if I can just figure out if I actually HAVE the Florida in amongst the several plants I bought. Sigh. I'm hoping the tags just got mixed up, but it's hard to tell without seeing blooms.

I have found I can keep some plants that are not my zone by surrounding them with stones , It seems to keep the ground temps just a bit warmer in the winter.
Might be worth a try
I use field stones and put them right on the soil with good ground contact about 4-6 inches from the base of the plant.

Good suggestion! Heh, and one thing we have in abundant supply here is rocks!

What do clematis look like when they are dying?

woofie, if the clematis came from the Cubits co-op and you think the tags were mixed up before they were sent to you, she'd want to know.

Oh, yes, I've already discussed it with Mamajack! She has offered to replace it on the next order. But I figure, I ordered 6 and I got six and I love clematis. So if one of these doesn't turn out to be the Florida, I'll just order another one. No biggie.

Okay.

Misty - to answer your question of "What do clematis look like when they are dying?" - they no longer have green leaves, generally are very limp and lifeless in all ways. That might also mean they have "clematis wilt". In either event, cut them down to the earth, apply a fungal treatment (Funginex), and hope they revive, which is possible.