Using shrubs is one way to take up room in a garden, but it is also possible to have tall perennials serve the same function. I have several tall perennials in my garden that I realize are not well placed, partly because they are overcrowding each other. I will be reorganizing them in the fall. In the meantime, I want to suggest some tall, dare I say statuesque, perennials that can make quite a statement in a flower border.
Right now, Filipendula rubra, queen of the prairie, is producing delicate pink astilbe-like flowers. The deeply cut, bright green leaves are as fragrant as the flowers. It is easy to grow, tolerant of wet sites and clay soil, and can reach 6 to 8 feet tall. But even though it can become very tall, it does not need staking, making it ideal for a back-of-the-garden border. It likes the sun, but can tolerate some shade. Tall plants like this make a really dramatic clump.
If you have a shady spot, Actaea racemosa, formerly known as Cimicifuga, and always also known as black cohosh, can reach a height of 6 feet. If the site is particularly fertile and damp, the 1- to 2-foot white spires rising from the dark foliage can reach a height of 8 feet. Depending on the site and weather, it can begin blooming in July, August or September. It stays in bloom for at least three weeks. This stunning plant also serves as a host plant and nectar source for the spring azure butterfly (Celastrina ladon). I had this growing in my Heath garden and it was a real attention-grabber, glowing as it did in the shade of an ancient apple tree.
Another tall native plant is Culver’s root, Veronicastrum virginicum, which will reach a height of 7 feet including the 9-inch spikes of small white flowers. It needs damp to wet soil and will bloom in July and August. To extend the bloom season, cut back the spent flower. You can even cut it back to the basal leaves and possibly get a second flush. Like the queen of the prairie, Culver’s root is a good choice for a rain garden. It also attracts butterflies.
Joe Pye weed, Eutrochium purpureum, is known to many people as a roadside weed, but there are different species in the Eutrochium genus. That explains why one Joe Pye weed in my garden looks nothing like the roadside variety, and the second Joe Pye weed looks nothing like either one because it has variegated foliage. What they all have in common is their size, up to 6 or 7 feet, and mauve dome-like flowers that appeal to many butterflies and bees. There is a dwarf Baby Joe that will not grow taller than 3 feet and has blooms in a deeper shade of purple. Joe Pye weed is another plant that will thrive in a rain garden.
Boltonia is another wonderful plant that can reach a height of 6 feet and will need little or no staking. Having said that, I have to say that the boltonia on the Bridge of Flowers is very happy to be able to lean on the wire fence behind it. From August through September, Boltonia is covered with tiny white daisy-like flowers. Once in a while, those white petals will have a pink or mauve tint. For a slightly more sturdy and compact plant, Boltonia asteroides var. latisquama, or “Snowbank,” at three to four feet tall might be a good choice if you are not necessarily looking for a statuesque beauty, but are looking for lush autumnal bloom.
I have two very tall perennials in my garden. Right now, my giant meadow rue (Thalictrum rochebrunianum) with its cloud of tiny lavender blossoms is about 8 feet tall. This is an unusual height; 6 feet is more common. It is a hardier plant than you might imagine after looking at the delicacy of its flowers and its foliage, which looks very similar to the foliage of the spring columbine. I planted it a couple of feet into the garden bed, but this spring, the few stems I had last year sent out about a million babies. I pulled out a lot of those babies, but it was hard to get rid of them all, even when I tried.
Right now, the meadow rue and the variegated Joe Pye weed look like passionate kissin’ cousins right at the edge of the bed. They will bloom into September.
The other equally tall perennial is Hemerocallis altissima. It has not yet reached its full height, but this daylily will be at least 6 feet tall. Like all daylilies, it has increased each year, and in the fall, I will have to divide it.
I have certainly not named every tall perennial available for the backyard garden. I visited a friend some years ago who used perennial sunflowers (Helianthus) to create a hedge on one side of his corner garden. Another friend lined a walkway with a profusion of lacy white fleece flowers (Persicaria polymorpha) reaching 6 feet tall. Delphiniums can be tall, from 4 to 6 feet, but there are smaller varieties as well. They come in a range of blues, and white as well.
A striking tall annual flower is the deep red Love-lies-bleeding, Amaranthus caudatus, that can reach 5 feet and is useful in fresh or dried flower arrangements.
Tall or small, there is always great variety for the flower garden.
Pat Leuchtman has been writing and gardening since 1980. Readers can leave comments at her website: www.commonweeder.com.