Late bloomers can keep gardens going through fall

The plants of high summer are on stunning display in gardens across Ozaukee County. Coneflowers, Joe Pye weed, perennial alliums, tall garden phlox and more are at their peak, much to the delight of gardeners, garden observers and a host of contented and busy pollinators. But the show won’t last until the end of the growing season. For that, gardens need a bit of help from late-blooming perennials.

These August-to-October bloomers, much like early spring bloomers, tend to be overlooked when many gardeners are shopping because they just don’t look like much then. But find a spot in your garden for them, and when the colorful show we’re ejoying now starts to fade, they will stand out. 

When it comes to late-season all stars, ironweed (Vernonia) should be at the top of the list. Although slow to emerge from dormancy in spring, once they get growing they move quickly and are often quite tall plants. The foliage varies from narrow to wide depending on the variety, but many of the newer, and often shorter cultivars have thread-like foliage similar to Arkansas blue star (Amsonia hubrictii). 

Ironweed flowers range from magenta to pink-purple and are sure to draw pollinators, including the native denticulate longhorn bee, which is an ironweed specialist. 

Among the top-performing varieties in a Mt. Cuba Center trial better suited sizewise to most gardeners is ‘Summer’s Swan Song,’ a hybrid selected at the Chicago Botanic Garden. Growing just 42 inches tall, it creates a nice mound of foliage. Although many sources suggest that ironweed is generally deer resistant, it will get taste-tested in my garden if I haven’t applied deer repellent.

Native asters (Symphyotrichum) are another late-season star that blooms for a long time. Although there are many good varieties, one that is often praised is ‘October Skies,’ which grows 1 to 2 feet tall. Like other asters, it can spread a bit more than may be desired but is easily managed with division every few years. Although some asters are targets for deer, ‘October Skies’ has slightly aromatic foliage that makes it less palatable.

Perhaps the most exotic looking plant of the late-season garden is toad lily (Tricyrtis). With arching stems that sport broad opposing leaves, the foliage is an excellent texture accent in light shade, but the real surprise is when it produces small orchid-like flowers along the length of its stems. It’s unlike any of the bolder flowers of the late garden and deserves a spot where it will be appreciated by the gardener and can be a surprise to visitors.

It’s not too late to tee up the late summer garden for a display equally as beautiful as it right now. In fact you’re more likely to find many of these plants available now, and while any flowers they produce this year are likely to be minimal, you’ll be setting your garden up for an excellent show that lasts through frost for years to come.