kimcoco, I don't know about the fertilizer schedules, but I did plant a sweet autumn this past summer. I do know that it is a type 3 that you want to cut back to about a foot tall every spring. SAC blooms on new wood so needs heavy pruning each spring. I can't wait to see what mine can do this next season!
The others, I would probably give them a good dose of fertilizer first thing in spring when danger of frost is past (like when you would prune the roses, or when forsythia's bloom in spring) and then another dose after the first flush of blooms is past. Don't fertilizer after August 15th to prepare them for winter.
I do have several other clems that are all either second year or going into 3rd year and I follow that schedule myself.
Hope this helps!

Here is a link that might be useful: I Quit!

Here's some more on fertilizing clems too. :)

Here is a link that might be useful: What do you use to fertilize?

Kimcoco, what are the names of the clematis that you have already planted? If they are type IIIs, they get pruned every year sometime during the winter (I do most of my type III cut backs in December-mine are already done for this coming year). Type IIs typically should be cut back the first if not the second year they are in the ground just so that they can get a good root system established.

As for fertilizing, normally you do it initially in the early spring once the buds start swelling. How frequently you do it and with what is really up to you. Some people use compost and/or compost tea, alfalfa pellets, grass clippings, tomato and/or rose food, purchased organic or synthetic granular time released fertilizers, soluble fertilizers such as Miracle Grow, etc. As you can see, there is a wide assortment of fertilizers you can use for clematis and if you ask 10 different people what they might use, you could get 10 different answers.

As to how frequently to do it is going to depend on which fertilizers you use, how fertile your soil naturally is, and why you might want to fertilize them. I will typically cut my type IIIs and type IIs back by anywhere from 1/3 to 2/3 after their initial bloom period to get another flush later in the season. When I cut them back, I refertilize them with whatever I am using or have on hand. Organic fertilizers tend to be slower release so you don't have to worry as much about over fertilizing when you do fertilize them using this type of fertilizer than if you used a synthetic/dissolvable type of fertilizer which is more immediately available to the plants.

Some people go way overboard with fertilization of clematis as far as I am concerned and you have to judge how the plants are performing or aren't to determine how much you need. Needlessly dumping tons of fertilizers on any plant just for the sake of fertilizing is not fruitful and can lead to a lot of green vegetative growth with few blooms.

As far as fertilizing when plants are blooming or coming into bud, it can be done provided you use a slower organic type of fertilizer. I have often forgotten, gotten sidetracked, or ignored fertilizing my clematis in early spring only to remember to do so when the plants were budded up or blooming and done so with compost, compost tea, mushroom compost, alfalfa pellets or some other organic fertilizer and not had it affect the bloom cycle.

Hope that helps some!

Thanks all. It's all coming back to me now. LOL.

Miguel, I have a lot of Viticellas, mostly type 3's, with a couple type 2's.

I recall using a slow release rose fertilizer, so I think that's the way I'll go. The majority of my clems have done well, regardless of my lack of fertilizing last year. The viticellas especially well. There are a few that grew spindly, but we'll see how they do going into the third growing season.

I will cut all type 3's back early spring...I won't cut them back all season like I had the first two growing seasons, however. I'll post pics this summer....I anticipate that my clems will cover my fence this year.

Kimcoco, there have been a few years where I did not fertilize my viticellas at all other than mulching them with some sort of organic material and they have done just fine. In his book entitled The Troublefree Clematis-The Viticellas, John Howells claims that the viticellas are not very heavy feeders at all. I tend to think that quite a few of the type III clematis including the American species are similar in their ability to get by with minimal feeding as long as they are mulched well with an organic material that will break down naturally to increase the soil's tilth. Like I said previously, I believe people go overboard with the whole fertilization bit on clematis. Of course I grow very few of the type II clematis since they don't like our hot and humid summers. Perhaps they might benefit from a more judicious fertilization protocol.

Thanks Miguel. I was thinking of adding organic composted manure to my planting beds in the spring anyway, so I'm sure that will suffice, my clems seem happy enough.

Sorry to hear about your Mom. I hope she is well.

I think a lot depends on your soil. If you have some naturally nutrient-rich soil like clay or humusy- clay, then plants that want a lot of nutrients like roses or clematis will do quite well with less fertilizer. If you're near Lake Michigan and are gardening on sandy soil like I am, then you can't possibly add enough compost/fertilizer/clay to your clematis as it all tends to wash away rather quickly.

For our zone, I cut back the type 3's in late February or early March before the buds swell up. For aggressive growers that bloom early enough (by early July) I cut them back by about 2/3 and fertilize/water well for a few weeks. Depending on the season, I usually get a strong 2nd flush with clean foliage. This year most did not respond this way due to the cold weather, but it just means next year will be full of blooms.