Some Like It Hot

Story & photo by Cindy Gilberg

St Louis summers can be sweltering, causing both plants and gardeners to wilt. Particularly challenging are those hot, sunny and dry sites in the landscape. Draw on one of the first lessons of gardening, “Don’t fight the site”, and choose some native plants that are found in these seemingly harsh environments. We can derive an outstanding plant list from the great diversity of native plants that thrive in the upland prairies and glades of Missouri, natural habitats with these conditions.

Much of this region was once covered in vast grasslands that the French settlers referred to as “prairie”, their word for meadows or grasslands. Glades are found just southwest of St. Louis and are another dry habitat that features many beautiful plants. This unique ecosystem is characterized by shallow bedrock, usually limestone, covered with a thin, rocky soil. Look around your own landscape and note where there is the same list of parameters—hot, sunny and dry.

Grasses and perennials that flourish in upland prairies and glades can be used to create a garden that, once established, requires little irrigation and extra care. Since this plant palette requires an average, well-draining and dry soil, addition of compost should be used sparingly. The organic-rich soils of many gardens can be too much of a good thing, causing these plants to grow tall and weak, sometimes resulting in decline and death. Keep in mind that design style is not dictated by a plant list and that native plants can work in any design style from formal to loose and naturalistic.

Grasses comprise a large part of the prairies and glades and their addition in the landscape lends a sense of place to Midwest landscapes. Two shorter species that work well interplanted or en masse are prairie dropseed and little bluestem. Their fine texture is a welcome contrast and the seeds in the fall are a favorite of birds. Interplant prairie dropseed with another perennial such as blazing star or butterfly milkweed to create an attractive ground cover.

The perennial list for hot, dry sites includes old favorites plus some lesser known species that have proven to perform well. A classic is false indigo (Baptisia), known for its late spring spires of blue, yellow or white flowers, depending on the species. For mid-late summer vertical accent, blazing stars (Liatris) are real stars. Not only are they butterfly magnets when in bloom but the ripe seeds attract droves of finches and other small birds. Purple coneflowers (Echinacea) are popular in many gardens for the same reason. However, in dry conditions, the regular coneflower (E. purpurea) struggles while the pale coneflower (E. pallida) and yellow coneflower (E. paradoxa) are content in these conditions. A ‘poster child’ for the native plant movement is butterfly milkweed (Asclepias tuberosa). It is the host plant for the monarch butterfly and its bright orange flowers attract many butterflies in search of nectar. For great fall color try the aromatic aster (Symphiotrichon oblongifolius). Its rich blue flowers offer a late source of pollen and nectar for bees, butterflies and other insects. Not as common but definitely a good addition is the white-flowering slender mountain mint (Pycnanthemum tenuifolium). Few plants surpass this one for its importance to pollinating insects. For along paths or in rock gardens, the Missouri evening primrose is a real beauty. Large yellow flowers open in late afternoon atop low-growing plants.

‘Right plant, right place’ is not a cliché, rather it is a way to ensure success in the garden. For plant lists by cultural requirements or general information on native plants, go to the Native Landscaping section at www.shawnature.org .

Cindy Gilberg is a Missouri native and horticulturist whose work includes design and consulting, teaching and writing. Much of her work focuses on native plants, habitat gardens and rain gardens. Cindy’s projects include work at Shaw Nature Reserve and its Native Plant School, the Shaw Professional Landscape Series and the Deer Creek Watershed Alliance. Cindy can be contacted at 314-630-1004 or cindy.gilberg@gmail.com.

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