I have a tamarisk, planted as a 1-gallon container about 3-4 years ago. I don't know if it's Pink Cascade or Summer Glow. Although it's healthy and grows just fine every year, I have not yet seen it bloom. By the end of the season last year it had reached about 3.5' in height. It has not suckered and so far has kept a narrow, upright shape. It gets cut back severely each spring as soon as I see some buds starting, which are generally only from below the snow line.

I have a number of shrubs and perennials in close proximity and have not had anything troubled by the tamarisk.

I've read that it is not invasive in a very cold climate.

I really think there isn't any chance this plant would ever become invasive in your area. I live in Zone 3 and am happy if I can get it to winter. It dies back and then tries very hard to get going but the cold weather always comes before it does much.So it's back to square one next year.

Zone 5 and I don't think it will ever get invasive here either.
It isn't a real speedy grower but I love the foliage.

I have read that the plant can be burned, cut and still root.
I am using rooting hormone on nice not-burned cuttings, and all kinds of tender care and am getting about 2 out of 3 to strike roots.

Worth a try if you want to grow more...

Karen