Can you recommend some flowering shrubs or tall perennials?
I have three street trees (Japanese Tree Lilac) planted on the north side of my Philadelphia house, 17 feet apart. I'm considering removing the sidewalk concrete between the trees. In this new space, I'd like to plant either flowering shrubs (I was thinking mountain laurel) or tall (3-4’) perennial flowers. I’d like to stick with native species. This area doesn't get much sun and the new plants or shrubs would also be shaded by the existing Tree Lilacs. Suggestions?
Answer
This is a difficult site, but I have a few suggestions. Google the names and see what you like and read the growing conditions for that particular plant so that you site it correctly.
Perennials:
Aruncus dioicus
Epimedium -- low, but a good shade plant for very dry conditions
Aquilegia canadensis
Shrubs:
Mountain Laurel (as you suggested)
Ceanonthus americanus
Fothergill gardenia
Hydrangea quercifolia 'PeeWee'
Spirea densiflora
Two suggested plants from PHS's Gold Medal plant program (see link below):
Itea virginica 'Henry's Garnet'
Clethra alnifolia 'Hummingbird'
I hope you can find some suitable plants from this list.