Mike Hogan
| Special to Farmers’ Advance
See Blendon Township woman’s native plant and habitat garden
Native plant & habitat garden at Alice Foeller’s home.
Alice Foeller
Depending upon the type of gardening you enjoy, August can be a month with fewer garden tasks and activities. If you tend a large vegetable garden, you are still busy with harvesting, doing battle with pests, planting fall crops and watering! But if your love of gardening leans toward the ornamental side, you may not be as busy tending to your flowers and other ornamental plants as you were earlier in the season. So, what should you be doing in August? You should be planting herbaceous perennials!
Herbaceous perennials
Perennial plants are those that go dormant in winter and re-grow the following season. Herbaceous perennials refer to non-woody plants such as shrubs and trees, which are also perennial plants. August and even September can be a great time to plant many herbaceous perennials which will provide flowers and color yet this summer and fall, and again next season.
Most year-round garden centers in greater Columbus now feature not just hardy mums or asters, but a variety of herbaceous perennials throughout the summer and fall, and many of these retailers discount these plants as fall approaches.
The typically cooler late August and September temperatures place less stress on these plants as they establish root systems, and insect and disease pressures typically decrease as we inch closer to autumn.
Choosing perennials for late summer planting
Here is a list of some flowering herbaceous perennials which thrive when planted in August and early September and can be found now at local garden centers and retailers:
Hardy hibiscus (Hibiscus moscheutos), also known as perennial hibiscus, are cultivars of tropical hibiscus which have been bred to tolerate colder temperatures of winter. Their dinner-plate-sized flowers feature thin, ruffled flowers in shades of pink, white, red and magenta. While these blooms only last a day or two, they are quickly replaced with new blooms.
Hardy hibiscus plants grow fairly large for herbaceous perennials and are the size of a large shrub when they flower, so give these plants room to grow when choosing a planting location. This plant is slow to re-grow in early spring when some other hardy perennials have long since greened up, so have patience in the spring and you will be rewarded with flowers (and dragonflies, hummingbirds and butterflies) next August.
Coneflowers (Echinacea spp.) are an iconic summer garden favorite in the daisy family (Asteraceae) and are in full bloom in greater Columbus right now. Coneflowers are distinctly identifiable by their daisy-like structure of outstretched colorful petals and their medium- to dark-brown or black central floret. However, there are clear differences in the appearances between the various species and genera. They come in multiple shapes with unique looking florets and variable stems. Petals also vary in color and in orientation.
These plants thrive in the full summer sun and heat with periods of drought and have long bloom times, which can be extended even further by deadheading which, if done properly, can encourage plants to bloom well into fall, sometimes even up until the first frost.
After blooms have faded in the fall, seed heads also become an important food source for songbirds such as the American goldfinch, and when flower heads are removed, the hollow stems provide winter nesting habitat for beneficial insects.
Black-eyed Susans (Rudbeckia spp.) are derived from North American native wildflowers and bring a wealth of ecological benefits to the garden. The halo of yellow petals provides a target and landing pad for many pollinators. A close examination of the center “eye” reveals that it is actually hundreds of individual small flowers, each holding nectar sipped by bees, small wasps, flies, butterflies and moths.
Several species of birds will feast on the mature, nutritious seeds of the flower heads if left intact at the end of the growing season, so save cleanup until spring.
In addition, black-eyed Susans provide a bright spot in your garden from mid to late summer. They make excellent cut flowers. Cutting them for bouquets, along with deadheading, will encourage more blossoms.
Salvia (genus Salvia) is a large genus of plants which have been used for their herbal and medicinal properties for thousands of years. Salvia is in the mint family and thus has aromatic foliage. Salvias are pollinator magnets and attract many different species of butterflies, bees and sometimes hummingbirds.
Perennial salvias like autumn sage are ideal for planting in August as the striking upright purple flowers will produce a strong root system while the soil is still warm before a hard frost or freeze arrives.
Water is key to success
Just because temperatures are cooler and days begin to get shorter, don’t be fooled into thinking that you don’t need to water newly planted perennials in late summer and fall. While less soil moisture is lost to evaporation during periods with cooler temperatures, if rainfall does not provide a minimum of one inch of moisture each week, supplemental irrigation will be required. This is especially critical for newly planted perennials which need to continue to develop root systems before a hard frost or freeze.
Mike Hogan is Extension Educator, Agriculture and Natural Resources and associate professor with Ohio State University Extension.
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