There are so many deep purple clematis that I would hate to guess. You can tell the pruning group by the time of year it blooms. As a guess I think that if it didn't bloom until June and July it is a type 3. In my zone 9 garden type 1 (Montana) starts bloom in early March, Type 2 late March, early April, and type 3 in May. If it were mine I would prune all vines on the plant back to just above the first leaf node late this month or maybe next month in your zone.
I hope someone from your zone will come along with better advice.

See, that's my problem. I'm afraid to do that, because it didn't bloom except below the part where I'd pruned the year after I cut it back. It didn't really take off and bloom hard on the new growth until the following year.

So by bloom time it seems to be a type 3, but it also seems to be blooming on the previous year's growth. I don't want to accidentally prune all this year's blossoms off.

But it is kind of scraggly and all over the place, too, so I feel like I ought to be doing something. Know what I mean?

Thanks for the response. I really appreciate it.

I live in your area and here's how I approach pruning - it's not the most conventional method but it works well for me. I have too many clematis and of different types to worry about too many specific pruning methods, so I either prune or I don't prune!

Type 1 or those that bloom before May - armandii, montanas, macropetalas and alpinas, etc., I don't ever prune except to control size and then as soon after blooming as I can manage.

Type 2&3 get pruned the same by me - 2's are generally most of the large flowered hybrids and bloom beginning around mid-May. 3's are late blooming clematis and start around the end of June. Some will continue to produce flowers until frost, others (like SAC) bloom the end of August into September. I cut all these back hard around the same time I prune my roses, about the beginning of March. By hard, I mean down to 3-4 fat buds.

This more uniform, all-the-same pruning method does delay the flowering a bit on the 2's but not significantly so. I also fertilize them well at pruning time. I have rabbits and use their manure but tomato or rose fertilizer works well, as does a good heaping of compost, which helps to conserve moisture at the root zone as well as supply nutrients.

These are not precisely the guidelines outlined by the experts, but then the methods they advocate are just that - guidelines - and can be adapted as you see fit. And as I stated this pretty uniform approach works great for me and you don't need to worry who's who.

If you purchased your new F&G show Nelly from Clearview, it is still a tiny thing and needs to be grown on for a season before planting out. Pot it up in a larger, 1 gallon pot with a quality potting mix and provide lots of TLC. This time next year, plant in its permanent location.

I also live in your zone and I also prune my group 2's as 3's, unless I get lazy and don't prune them at all, which I don't recommend.

Then I'm sorry as I spent two hours yesterday trying to sort out the tangled mess Daniel Deronda (group 2) was in after not pruning it last year. I finally ended up hacking almost everything down. I'm not worried. It will be fine. I wanted to keep some growth longer as I'm trying to train it to reach the top of an arbor instead of sprawing horizontally on the neighboring shrubs and I did manage to salvage some.

I didn't used to prune my 2's but discovered they grew much better and bloomed much better if I did. The difference has been amazing on some plants.

I pruned several Group 1 Macropetalas and Alpinas hard last year because they were scraggly and it made a huge difference in their growth too.

Yes, I did buy my F&G show Nelly from Clearview. Thanks for the information about how to deal with it.

I guess I'll just see if I can get brave enough to prune the other one. I'm just terrified cutting it back will give me no blooms this year, since cutting it back hard before did almost completely eliminate blooms the following year.

Heh. I went back through my garden journal (it's a good thing I keep records) and it turns out that clematis bloomed in May last year, not July as I remembered. At any rate, it's got a lot of foliage buds swelling right now (in spite of the non-sticking snow we had this morning and the 40-degree temps we've had for the last week), and I think what I'm going to do is give them a bit longer to show themselves, then prune any vines back that don't bud out. If it doesn't work this year, then I'll try something else next year.

But I really do think this plant is blooming on last year's growth.