OK newbie, here ya go!! :-) Clematis perform best when pruned in late winter/early spring, about the same time you would prune roses or when forsythia blooms in your area. So like now. Clematis vines tend to bud out early so not at all surprised to hear buds already present along leaf axils, particularly given as mild a winter as many of us have experienced.

You want to cut it back now. Nelly is considered a group 2 so light pruning is generally recommended, however a harder pruning - down to the third set of buds - won't hurt it any more than a possible delay of initial flowering and can be helpful to clean up the tangled mess these vines sometmes produce. Once pruning is complete, fertilizing is next on schedule :-)

What gardengal48 said. Prune it. Now. :)

OK, thanks. The vine is about 4-5 feet high. How low should I prune it?

Prune it down to the lowest two sets of buds on each stem.

Work from the ground up.

OK, I grabbed my pruners and snipped off all but the first 2 leafing nodes from the ground on my single vine. That's all there is, there are not multiple vines. Just this thin brown dry vine, now with 2 leafing nodes, to pin all my 2012 flower hopes on. I hope this vine does not disappoint me again like it did in 2011--with only ONE crummy flower for the whole season! Hopefully Year 3 will be the one.

Read the thread titled "didn't prune my clematis" down a post or two :-) Planting the root crown deeply, hard pruning for the first couple of years and fertilzing with alfalfa meal or tea are all methods to encourage multiple stem generation from the root crown. The more stems, the more robust and healthy the vine and more improved/heavy flowering it should be.

I had put down Plant-tone organic fertilizer when I planted the clematis and supplemented it with Osmo-coat. The crown is planted pretty deeply, and there is shredded bark mulch on top of the soil. I hope this snip I executed Friday will result in more stems and more flowers this year!

Osmocote is really best for container annuals rather than perennial vines like Clematis.

Alfalfa has a hormone that encourages additional vines to grow from the crown. You can buy a big bag for about ten bucks at a farm/ranch/feed store. Cheaper than a little box of meal at a garden center/nursery.

When all you have is one long scraggly stem pruning down to a foot or six inches encourages more vines up from the crown as well.

Clematis are not instant gratification plants. Especially the Type IIs like Nelly, it can take more than three years before you get many flowers. Having multiple vines and pruning and pinching really encourages more flower buds.

Could I use alfalfa pellets meant for rabbit feed? I live in NYC, we don't have farm/ranch/feed stores! But we DO have pet shops that sell pellets of compressed alfalfa. Would that serve the purpose? How would I apply that?

Thank you for all your advice. I hope my Nellie will be worth it!

Rabbit feed probably has salt in it so would not work. You want horse feed which is pure alfalfa with no additives. I just scatter it around the base of my plants and cover it with mulch. You don't even need to cover it. As it rains or you water the plant the alfalfa will dissolve and get to the roots of the plant. Check the ingredients if you can't find the horse feed. You don't want to add salt to your soil.

You are correct. When I checked the rabbit food ingredients, it contains some salt. Getting horse feed here in Queens is not going to be easy. As I said, we don't HAVE feed stores for large animals. Just pet food stores. I think they carry alfalfa hay for bunnies in addition to the compressed pellets (with the salt), but that's it.

Zilla makes a reptile bedding that's locally available, which is made of alfalfa. The ingredients are: Dehydrated alfalfa meal, roughage products, grain products, sodium bentonite, propionic acid.
Would that be suitable for this clematis purpose? I don't see salt listed, just the bentonite.

I wouldn't use it. If you can't find pure alfalfa I would pass on it. Although it helps you can get good results by proper pruning and using a good fertilizer and mulch. Keep the plant watered so the roots don't dry out and it will develop the vines you want. If you ever visit an area where there is a feed store buy a big bag of the pellets.
I think most bedding products contain materials that absorb moisture and maybe harden after they do so I would avoid it.

Aha! I found some alfalfa cubes which are 100% alfalfa and no salt or anything else. And, they are sold at a pet shop 5 minutes away. Sun-Seed alfalfa cubes for rabbits and guinea pigs, $6/bag.

Solved!

OK, Bob. I went to Petland and bought the 100% pure alfalfa cubes. I took 3 of the largest ones and put them into a large dispo cup with about a cup of hot water to soften them. Then I mashed them up and heaped them around the clematis vine, where it emerges from the ground. Hopefully that should do it, right?

That should do it.