Late Summer Flowers Q&A

By Pat Curran, Horticulture Educator,

Tompkins County Cornell Cooperative Extension
(Published August 2011)

Question: What can I plant so that my garden looks lush in late summer, instead of tired?

Answer: Lots of plants flower in late summer. Sometimes they don't look very impressive in pots at the nurseries in spring, and we overlook them. Daisy relatives such as Helenium (available in reds as well as yellow and orange), Heliopsis (yellow, medium height), and Silphium, cup plant (yellow, a graceful 6 or 7 feet) strike a strong color note that can be nicely set off by tall white phlox and lavender-blue Caryopteris (a small shrub). Tall phlox, with its wonderful fragrance, also comes in many shades of pink, lavender, almost true-blue, and fuchsia. Russian sage in lavender-purple likes it hot and sunny. Native cardinal flower blooms in red, and its relative, the wild blue lobelia, in bluish-purple. Native turtlehead blooms a nice medium pink, while native Joe-Pye weed is a dusty rose. Purple coneflower is flowering abundantly. An edging plant I love, twisted onion, Allium senescens glaucum, will soon be covered with little lavender-pink globes. For partial shade, there is the low-growing Astilbe chinensis pumila with lavender-pink spikes, and just starting now, the hybrid anemones in pink, rose, or white. Heuchera, now a wonderful foliage plant in many different colors, thrives in dappled shade.

Shrubs provide color with red fruits (Aronia, Viburnums), or blue or white fruits (native dogwoods). The old-fashioned PG hydrangea is now available in new improved varieties, as is the Rose-of-Sharon bush. The bigleaf hydrangea is now available in varieties which will bloom despite the cold winters that may kill overwintering flower buds. Native Clethra, summersweet, is fragrant and very adaptable as to soils or sun exposure.

Tender plants such as dahlias and cannas are at their best now, if they have been kept well-watered. Containers of these can be positioned in gardens that have little late-summer interest, but then watering is more difficult. Grouped on a deck or patio, they can be very showy, as well as easier to maintain.

Ask a Gardener appears weekly in The Journal during the growing season. For answers to other garden, lawn, landscape and pest questions, call Cooperative Extension at 607-272-2292 or email: growline1@gmail.com.

Last updated January 29, 2021