If I had access to well rotted and composted horse manure, I would use it in a heartbeat. You may get some weed seeds to germinate in it over time, but the added fertility and tilth the manure will add to the soil will more than make up for the inconvenience of having to pull a few weeds.

I have also used llama droppings that were not composted and like them as a fertilizer.

Thank you so much for replying to both of my messages. I think I will try the rotted manure and see what that does for my Clematis.
Lois

Just make sure it is still not hot and truly rotted out or you may burn your clematis. Start off trying a smaller amount and watering it in and then seeing what happens. If the plant responds well or at least doesn't seem to get burned from it, you can always add more over the growing season.

I saw a listing on craigslist from someone very local which has aged horse manure and got a response today.

They have truckload after truckload of good coal black manure which is several to many years old! :)

Price is donation for their handicapped riding program which will go towards a very good cause. I plan to go there this weekend and get several truckloads of it!

Stupid question here and not clematis related but I read on a gardening site that you should be concerned about using this in vegetable gardens due to risks of E.coli?

It depends on exactly how "well aged" it is as to whether there are any viable pathogens remaining. It is recommended that it be at least 12 months old or fully composted before using it on edibles. There is no harm in using sooner on any ornamental plantings as long as no distinct 'manure' aroma remains - that will ensure the manure is not still too hot (high nitrogen content) to burn plants.

Thanks Gardengal, this is several to many years old so it won't be a problem.

All the clematis that I planted last fall need more soil so before adding mulch this spring I'm going to put some of this around each one.