Giants in the Garden

Late summer can be a time for bold floral statements, with tall perennials towering over the remains of those that have finished. It’s almost like the garden keeps building on itself, with late summer flowers being the tallest of all. If you’d like to add a little more height to your garden, consider some of these native giants.

Rudbeckia laciniata rises above the fence

In my garden, cutleaf coneflower (Rudbeckia laciniata) has had a very good year, reaching heights and flowering stem counts that I’ve haven’t seen before. We must have had good rain right when it needed it. It can reach 8-9 feet tall in ideal conditions, which for this plant is moist and mostly sunny.  Bees and butterflies appreciate the flowerheads which are composed of tiny disk flowers in the center and bright yellow ray flowers at the edges.

A couple of other moisture-lovers are ironweed (Vernonia spp.) and hollow Joe Pye weed (Eutrochium fistulosum).  Both of these are often found near me in low, wet ditches where they are covered with pollinators. Some of the ditches are so deep that if it wasn’t for their height, I wonder if we'd even notice these two? It is a joy to see them stretching above the other plants, the jewel-like purple of ironweed catching your attention at any speed while the soft, billowy blooms of the Joe Pye weed are almost too airy to notice above 40 mph.

Eutrochium fistulosum

Vernonia gigantea lives up to its name

Some of our perennial sunflowers can be quite big. Blooming now is Jerusalem artichoke (Helianthus tuberosus) and I drive every year past a wonderful garden full of it at an old house. People still live there and the patch is well-tended, with the plants easily reaching 8 feet tall. Perhaps they harvest a few tubers for pickling. Next month will bring the tall bright blooms of swamp sunflower (Helianthus angustifolius). By the time that the 10-foot stems are blooming, they usually could use a little help with staking (especially if we get a summer thunderstorm). Count on people asking you about your plant if neighbors can see it.

A large stand of Helianthus angustifolius at a nature center

Similar to the sunflowers are the rosinweeds (Silphium spp.). They’ve already finished blooming now, but species like cup plant (Silphium perfoliatum) and kidney-leaf rosinweed (S. compositum) can easily reach 8 feet with numerous yellow flowerheads. Kidney-leaf is my favorite because of its handsome foliage.

Cirsium altissimum

Blooming now in my yard is an oft-overlooked group of biennial plants – the native thistles (Cirsium sp.). I have come to love these prickly giants as I watch bees, butterflies, and hummingbirds take delight in their flowerheads. I know the goldfinches are probably equally happy with the seedheads afterwards. Two years ago I had one so tall that I could stand on the deck and take pictures of butterflies on it from above.

Silverplume grass (Saccharum alopecuroides) can be spotted on the side of the road now. The flowering spikes can reach up to 10 feet tall and a small group of them is a very pleasing sight. The wide, strappy blades can be a very attractive and bold statement as well. It likes lean, well-drained soil – you know, like a roadside!

Silverplume towers above the field (Saccharum alopecuroides)

Another good native grass is Indian grass (Sorghastrum nutans) which might only reach 7 feet. It would pair nicely with big bluestem (Andropogon gerardii), no shrimp itself at 8 feet. I love how the Mimsie Lanier Center for Native Plant Studies at the State Botanical Garden of Georgia grows some of these native grass from seed for their Connect to Protect Native Plant Sale in the fall.

So, if you're looking for some plants with late-season oomph, look for some of these.