I am in zone 5 like you, and have had this sedum "Hot Stuff" in my garden for several years. It never flops but is only about 10-12" tall. I am showing you this because of its color, it is a really bright pink. I took this photo today. They have been blooming for several weeks and the color is still great while my Autumn Joy are starting to fade and brown. I really love this sedum and thought you might want to consider this one.

Sherry

âÂÂFrosty Mornâ is my favorite. It loloks great when it is not blooming and looks even better when in bloom.
The picture below was taken in early August when its flowers are just beginning to emerge whiite, right now its blooms are larger (but not too large) with pretty pale pink flowers. I will try to take a photo today.
The only thing to consider: in order for it to stay short, bushy and not floppy, cut it by half in early July.
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Green- I like that one....frosty morn.... How tall does that one get?

I have an "Autumn Delight" which is similar to Joy/Fire etc except the foliage is very chartreuse and slightly variegated. The blooms are more of a vibrant pink (similar to the "Hot Stuff" above actually, but gets to about 18-20").

Mine pretty much looks like:

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Autumn Charm?

If not trimmed in July, âÂÂFrosty Mornâ sedum will get tall and floppy just like âÂÂAutumn JoyâÂÂ.
However, if trimmed, it will be half that size.

Frosty Morn today. Blooms are already starting to fade out:
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Close up
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Sedums like it hot and dry. The clethra will not be as happy in those conditions. Maybe not the hydrangea either.

You are making me want one of those green_go!

Green_go- yes, I love those! I think they will look great with the little lime. I think I will have to wait until next spring to find them though.

laceyvail- I am rethinking (maybe a little buyers remorse?) the clethra. I already bought 3 of each so I need to find a place for them somewhere...but I am becoming concerned about the overall space they might need width wise in my bed. I don't want to crowd out the Viburnum Winterthul I am spotlighting in a large corner of the bed (7 x 7 area). So I will probably move the clethra out of that bed altogether (nothing is planted yet I am just playing with them in their pots right now).Thanks for your insights on the growing conditions!