Well, y'know, there's a difference in a plant tolerating shade and thriving in shade. Sun lovers will not thrive in shade. They may do fine in part-shade, though (4 hours sun), I have found a lot of plants generally considered full sun do quite well in 4-5 hours of sun. Not shade, though. They may survive (i.e. tolerate) but they won't perform their best. BTW, Knockout is marketed as a part-shade rose, and yes it does indeed seem to do quite well under trees. I have a lot of experience with rugosa roses, and believe me - they don't throw the blooms in shadier locations like they do when the get more sun. Again - they tolerate the shade, but don't thrive. 4+ hours of sun is needed for good growth and flowering of a rugosa in this zone.

NHBabs - you are so right. I decided that I didn't want this plant in my yard so I went over to the house ( we're renovating it and haven't moved in yet) to get rid of it and while I was there I checked the whole yard and this thing is coming up everywhere! I pulled up a bunch but I can see that this will be an ongoing project. That and the air potato vine that I've been battling.

Avoid the following trees because they have shallow roots that push up and crack paving: Norway, Sugar, Silver or Red Maple; Pin, Live or Willow Oak; American Elm; Ash; Beech; Sweetgum; Tulip Tree; Hackberry; Poplar; Cottonwood; Sycamore; Plane Tree; Willow; and River Birch. Tillia Cordata "Littleleaf" (Littleleaf Linden) is hardy to zone 3 and provides dense shade. This cultivar supposedly grows 30 to 50 ft. with a spread of up to 30 ft. Fragrant, creamy yellow flowers in drooping cymes appear in June. Honeydew and bird guano are a constant threat with parking under trees. That does not mean these problems will be overwhelming. Your first problem will be waiting for the tree to grow large enough to cast shade. Make note of where the sun rises and sets. It's much better to have shade in the afternoon when the temperature is highest.

Back again to say, Merkity, I think you are right! There are bush hollyhocks that don't bloom in that tall spire I was thinking of! The leaves were so much like hibiscus, I thought of that first! Thanks!