Yes, and the honest list is short. Purple coneflower is the one that carries a documented rating for partial shade, and it does flower there. Most of what gets sold as purple flowers for shade comes with no shade rating at all from an extension service, so you are guessing the day you plant it. Coneflower gives you something firmer to stand on, and it is worth knowing exactly how far that goes before you dig a hole under a tree.
The far end of my driveway bed runs under a maple. The coneflowers I set down there open a handful of blooms, while the same plants at the sunny end are covered in them. Same soil, same planting week, same packet of seed. The shaded ones look healthy and the stems hold themselves up without staking. They just do not make many flowers.
Shade gets measured in hours of direct sun, not by how dark a spot looks at noon. NC State Extension counts 6 or more hours as full sun and 2 to 6 hours as partial shade. Go out on a clear day and look at the bed in the morning, again at noon, and once more in mid afternoon, then add up what it really gets. That number tells you whether you are shopping for partial shade flowers or for the much shorter deep shade list.
Coneflower blooms best in full sun. It will grow in partial shade and still flower, but it makes fewer blooms there, and that is the full scope of coneflower shade tolerance. The plant does not sulk and it does not flop. You get less color out of the same plant, so set more of them in the dim end of a bed if you want the display to match the sunny end.
Below ground the plant asks for very little, which helps in a bed where tree roots already own the space. It takes clay, loam, sand and even shallow rocky ground, at a soil pH of 6.0 to 8.0, so long as the water moves through. The one thing it will not put up with is ground that stays wet, and a shaded bed dries out slower than an open one.
Other purple perennials worth looking into are Hosta, Astilbe, Brunnera, Pulmonaria and Polemonium. I am not going to hand you a shade rating for any of them, because the list I am working from names them as purple perennials and stops there. Pull up your state extension's plant listing, find the name, and read the light line before you spend money. That beats trusting a nursery tag that says shade tolerant without naming a single hour.
Under 2 hours of sun you drop below the partial shade rating the extension services publish, so look at purple leaves instead. Ajuga and Heuchera both carry purple in the foliage, and so do Cimicifuga and Japanese maple. The color holds from spring through frost, while most flowering perennials are in bloom for only a few weeks. These are foliage picks and not proven shade bloomers, so look up what light each one needs before you buy.
Track one clear day of direct sun on the bed before you order anything. 2 to 6 hours puts coneflower in play with a smaller bloom count. Under that, buy purple foliage and skip the flowers.
Here is how I would split it. Give the sunny half of the bed to coneflower and hand the dim half to purple foliage, which holds its color all season with no sun math involved. You end up with purple in both halves, and only one of them depends on hours you may not have.
Read the full article: 10 Purple Flowers Worth Planting
