Ask a Master Gardener: MBG Fall Plant Sale: A Perennial Favorite

Texas Star, Hibiscus coccineus. Photo by Brenda Bolton

By: Brenda Bolton, Mobile County Master Gardener, www.mobilecountymastergardeners.org 

In 1728 the famous American farmer-botanist John Bartram founded the first botanical garden in America in Philadelphia, PA.   An avid self-taught plantsman, Bartram distributed an untold number of New World plant species to the Old World from our lush old growth forests and diversity of shrubs and flowers.

That history undergirds the Mobile Botanical Gardens, quietly created in 1974 by a small group of visionary founders who knew that Mobile’s rich florae deserved to be preserved and shared. Among the many gifts the MBG provides are twice-yearly plant sales offering a wide range of cultural heritage, heirloom and native plants ideally suited to Mobile’s growing conditions.  (The particulars of the sale are listed in Garden Events.)

Perennials are plants that return two or more seasons from an original root and typically need 3 seasons to develop their best display, year one to establish, year two to expand, year three to shine.  Some perennials also spread by reseeding in addition to resprouting from the old root.  Be prepared for perennials’ need for rest; they work hard.  Perennials have “down time,” or dormancy, to recuperate and ready for re-emergence.  Some, but not all, tolerate being cut back during dormancy to neaten the bed.

Keep dormancy in mind when deciding where to place perennials – don’t make perennials your front door feature unless in a container that can be relocated during dormancy.  Using different methods to handle dormancy, some gardeners place beds for pollinators out of public view or plant in containers to move out-of-sight. Some mix annuals, small shrubs, or opposite-season perennials to carry the bed when the perennials are resting.  And some simply delight in the natural rhythm of perennials’ comings and goings, leaving dormant brown seedheads to feed wildlife and make new plants.  Be sure to mark where perennial root masses are so you don’t disturb them when they disappear into dormancy. They come back, so watch for those tiny green tips to break the soil surface.  Every year is a small miracle. 

The successful use of perennials requires research to identify those with similar culture needs (soil, light, water) for planting in a single bed.  Start the installation with a soil test (test kits available at the Extension Office, 1070 Schillinger Road N) and carefully identify and avoid all potential underground obstructions, utility lines, outdoor lighting or irrigation system lines, cable lines, even DIY projects with underground piping or wiring.

Now, come outside with me and find a spot for your new bed.  Over there, against that fence, make the magic happen!  In part-sun and light open shade, where the lawn slopes down just enough for even moisture while draining well - that space begs for a happy mix of perennial blooms.  Here is a sample design using like-culture perennials offered at the Fall Plant Sale for a simple perennial starter-garden against that blank fence, all plants for part sun and evenly moist but well drained, neutral to slightly acidic soil.  A front edging that gently curves into a half-moon is perfect for an informal display of fall perennials spilling out of their earthen container for a lovely autumn floral arrangement.

First, consider using the fence to support the native vine Lonicera sempervirens, with its narrow scarlet trumpet blooms.  Plant a back row of 5-6’ tall perennials, sloping down to mounding fullness in the middle and on the sides, airy fillers throughout, and low edging defining the front.  Leave space between plants for growth, or for interplanting annuals or spring perennials for year-long blooms. 

In the back row, use several each (depending on bed length) of red Firespike, Odononema strictum, red v. Big Momma Turk’s Cap, Malvaviscus drummondii, sprinkled with happy native Swamp Sunflower, Helianthus augustifolius, all 5-6 feet tall. 

In the middle and to the sides, 3-4 feet mounding Clethera alnifolia, v. Ruby Spice, Aesclepias incarnata  v. Pink Swamp Milkweed for the Monarch butterflies, and native Hibiscus coccineus v Texas Star, as filler. Toward the front center of the border’s half-moon curve, cluster clumps of coneflower, Echinacea purpurea, growing to 2 feet tall. The multi-hued variety Cheyenne Spirit, with blooms ranging from yellow to deep pink to peachy orange, is stunning. 

Finish the bed with the low front edging plant native Stokes Aster, Stokesia laevis, in single or multiple colors, v. Honeysuckle Purple, Peachies Pick, or Divinity.

Go to the sale on Oct 9, 10, or 11, and you can install your perennials before sundown on Oct 12. Water deeply in mornings at the roots, then as needed for a month.  Don’t overwater coneflowers to avoid mildew. Next year will be a longer bloom season, bigger, better and filled with fall’s butterflies!

Stokes Aster, Stokesia laevis. Photo by Alice Marty

Turk's Cap, Malvaviscus drummondii. Photo by Alice Marty

Red Firespike in early fall. Photo by Aven Warner