Hopefully Jeanne will see your post soon. She lives in Texas and is very successful with Clematis.

I would not bother with soil samples. Most of us use organic rose type fertilizers and/or compost and alfalfa tea.

Hi Kathy!! From Willis, Texas!!..You are doing the right thing by watering the heck outta it during our hot & dry summers..for clematis LOVE to have their roots stay moist..not soggy but moist....the reason your sister is saying it is bigger than ever is most likely because it is getting more sun now...if it hasn't set buds yet you can give it some rose fertilizer...post pics when it blooms and we'll try and give you an id and what type of pruning will make it the happiest....Jeanne

Ah, rose fertilizer. I have that. Thanks for the tip. I have an old window screen over it now. Should I take it off? It really isn't much shade, but it shatters that hot sun.
I sure hope that Dolly brings us enough rain to fill our tank back up.

I was just telling my husband last night while watching the news that I hoped Hurricane Dolly moves more North so we'll have the benefit of the rains!!..where in Texas are you??..If you are zone 8 then you must be more North of me..I am only about 20 miles North of Houston...I would take the window screen off if it was me...as long as you are watering it..it should be fine..goodluck on the rain!!..Jeanne