Some summer annuals can remain in fall containers
With Labor Day behind us and school back in session, our thoughts turn to autumn. While it is not yet time to head to the pumpkin patch, it is time to update our containers for fall.
Before discarding all the annuals in your pots to fill them with mums, ornamental cabbage and kale, pansies and fresh crops of annuals, you may have some plants happy to accompany new companions into the new season.
Alyssum
If alyssum charmed the edges of your containers with their sweet-smelling flowers in summer, they will love the cooler temperatures September and October bring. They are cute tickling the foliage of ornamental cabbage and kale and mingling with pansies. If they have grown a bit leggy, cut them back and new growth will quickly begin.
Calibrachoa
Commonly called million bells, fresh crops of these are available at many local garden centers. But why buy new plants when the ones in your summer containers are still performing? If they need a bit of pruning, go ahead and give them a haircut, but the plants in your pots are firmly rooted in, ready to produce even more blooms in cool weather.
Dahlias
Dahlias have bloomed like crazy all summer long in pots on my deck and they get even better in fall. Let them stay until frost blackens their foliage. Then their tubers can be dug and saved inside for replanting next spring.
Geraniums
The brilliantly colored blooms of geraniums sizzle in summer containers, but in very hot summers their flowers may fizzle. Cooler temperatures revitalize geraniums and their blooms add sizzling shades to fall designs, too.
Kale
If Red Bor kale was used as the thriller in your container all summer, let it keep on thrilling your fall planter. Plants growing too tall can be replanted, with some of its stem buried beneath the soil to reduce its stature. Its deep reddish-purple foliage is beautiful with gold, pink and red mums and orange pumpkins.
New Zealand phlax
New Zealand phlax (Phormium tenax) is commonly chosen as the vertical element in containers for its reddish-burgundy or variegated, swordlike foliage. Its dramatic form is just as impressive in fall with mums and pansies as it was in summer with flowering vinca and marigolds.
Purple fountain grass
The grassy form and fluffy seed heads are in their prime in summer containers. Why take them out now? If you already have it, you are a step ahead. The first frost may turn their reddish-purple foliage tawny brown, but it is still quite attractive
Marigolds
Marigolds are often replaced with cool-season annuals, but they continue to bloom in cool weather, too. If marigolds were players in summer containers and are still performing, leave them in containers for a final act in fall.
Herbs
While frost will cause the demise of basil, many herbs thrive in cooler temperatures. If containers of herbs are waning, replant mint and thyme to fall over the edges, sage to mingle with pansies, and rosemary to add texture to fall planters.
Use a garden knife to cut around summer-worn or frost-sensitive annuals to reduce the root damage of annuals allowed to remain. Feed the plants that made the cut with an organic, all-purpose fertilizer to re-energize them for the new season ahead.
Go ahead and get mums and pansies to give containers a seasonal update but save time and money by keeping summer annuals that continue to perform in cooler weather. And plan your trip to the pumpkin patch.
• Diana Stoll is a horticulturist, garden writer and speaker. She blogs at gardenwithdiana.com.