My 'Ruby Spice' is not a strong red in flower (more toward pink, but it doesn't fade out either), nor does it have wonderful fall foliage. It does slightly sucker, but the suckers are easy to dig up - I pot some of them and toss others, depending on if I think I can find a spot here or someone to give it to. However, it is attractive, if a bit late to leaf out. I have it in all day sun, facing SE, in a raised, added bed in front of my porch - it grows about 4', maybe a bit more. I think I would be reluctant to have it as a front-of-the-border plant, though - it is late to leaf and it is a bit leggy for me - which may owe more to the perennials surrounding it than its native habit, judging from the above photo! A better plant for you may be the Fothergillas, or what about one of the evergreen azaleas - I think there are several that would be hardy for you - many of them have foliage that bronzes in winter (it goes back to green with spring). If the Encore series is hardy, you would probably get 2 seasons of blooms. Iteas might be better looking than the Clethra - for me they are a bit smaller, and there are several with spectacular fall foliage ('Henry's Garnet' and "Saturnalia' come to mind) - the flower shape is similar, if smaller and more drooping, and white. If you really want an evergreen, there are any number of different, variegated, conifer species/cultivars that stay smallish, and which have colorful foliage. You could also try a colored-leaf shrub, such as one of the variegated Caryopteris (there is another beside 'Worcester Gold', but I forget the name), with late season blue flowers, or one of the variegated Spireas ('Goldmound', 'Limemound', etc.), with pink flowers in summer. Both will stay 2-3', and can be kept in check by pruning out a third of the stems annually, after it has grown enough. An Abelia, one of the smaller cultivars, could also be good - white or pinkish, summer flowers on arching stems, 'John Creech' is evergreen here. I would avoid most of the barberries, as almost all the ones around are developed from the basic Japanese species, and it has proven invasive in the SE. Pity, because there are some very nice garden forms....

What do you have in Canada that is the equivalent of our research based extension system? I've often wondered but have never found out the answer to that. Surely there are places where pH tests can be evaluated. Since you have no idea what the pH of your soil is, I strongly suggest that you add absolutely nothing until you do know. How much? How much product to add to raise or lower the pH? That answer will depend entirely on what your existing pH is now, and on the soil type you have. You may find that you will need to add nothing at all. That is, of course, preferable to having to incorporate a product every year for the rest of your precious life!!

Thanks

I think you'll love any Clethra you choose, but Ruby Spice is a fine plant with its pink blooms. In IA, I doubt that you'll have any problem with it "running amok", though you can enlighten us if it does. I'd bet your biggest issue will be its moisture regime. Near the house usually means it will be in a bit of a rain shadow. Don't let Clethra run dry too long; it will turn (brown) on you like no other. If you can steer downspouts to drain on them, you will be handsomely rewarded. You don't say how high it is to the window sill. Clethra, in many years (7, 8, 9, I forget) next to a downspout here in heavy clay neutral soil KY, has yet to reach 5 feet tall. You will get much different comments from east coasters with acid sandy soils where it is native. Can't say I would venture exact performance in IA, but I think many years before it would reach 5-6', and even then, you could prune out any of the taller stems and the plant will grow more since it is a colonizing species. Managing this plant at 3-6' in the midwest should be fairly easy.