September in the Perennial Garden
The middle of September. That strange in-between time. The end of summer, but fall not really here yet. The weather—s all over the place: it could be 45, it could be 85. And the garden? It can have that exhausted end of the season look with plants struggling to put out a few more blooms with the last of their energy. But, if you plan it right, your herbaceous beds can look vibrant and fresh as spring. You just have to know what to plant.
Late season bloomers are taking center stage at Maxwell Arboretum—s Yeutter Garden and Fleming Slope. Japanese Anemone (Anemone ×hybrida) is a species that deserves more attention. It prefers part sun, but will tolerate shade so it—s a good substitute for the tired impatiens/hosta shade bed. It will also give you some nice height in the late season garden. The cultivar at Yeutter is —Whirlwind,— a pure white semi-double that blooms from mid September to mid October.
Plumbago (Ceratostigma plumbaginoides) can—t be beat for tolerating a wide range of conditions. It blooms August through October in full sun along a south-facing street curb with no supplemental irrigation, as well as at the bottom of Fleming Slope—a moist environment with full shade in the afternoon. As fall progresses, its foliage turns a deep red.
Plumbago—s late season blue blooms are complimented by Blue Mist Spirea (Caryopteris ×cladonensis, not a true spirea), a —sub shrub— that flowers from late summer into fall. Turtlehead (Chelone lyonii) is another underutilized September bloomer. Its deep green foliage creates a wonderful backdrop for the distinctive pink blossoms that give the plant its name. On Yeutter Berm you can find the straight species as well as the cultivar 'Hot Lips'.
These are just four examples of the myriad of late season bloomers that await you at Maxwell Arboretum—and await your green thumbs so that you can try them in your own yards. Here's a list of other herbaceous plants and sub shrubs to look for when you visit Maxwell Arboretum this September:
Gaura lindheimeri White Gaura
Heliopsis helianthoides 'Summer Sun' False Sunflower
Helenium autumnale 'Rotgold' and the species Sneezeweed
Solidago 'Crown of Rays' and 'Golden Baby' Goldenrod
Lagerstroemia Fleming Filligrees 'Coral Filli' 'Red Filli' 'Violet Filli' Hardy Crapemyrtle
Aster novae-angliae 'Purple Dome' and 'Alma Potsche'
Dendranthemum ×grandiflorum 'Clara Curtis' Chrysanthemum
Sedum 'Autumn Joy' Sedum
Boltonia asteroides 'Snowbank' Boltonia
Remember to stop deadheading many of your perennials at this time to insure winter interest seedheads. In addition to providing beautiful seedheads, planting grasses, especially natives, will add great color, texture, and movement to your late season garden.