March may be the most anticipated month in the gardening year as the growing season approaches. It brings the beginning of meteorological spring (March 1), astronomical spring (March 20 this year), and gardening signs of spring that vary with temperature, moisture, and day length cues. Garden tasks include trimming and monitoring, as well as finalizing plant orders. We hire summer student gardeners and create the garden volunteer calendar. Preparing for the season and eagerly looking forward to spring weather go hand in hand.

Many homeowners have sunny sites or areas with full sun for six or more hours a day. These are ideal for planting diverse mixes of prairie and sun-loving savanna species. For plantings near sidewalks and driveways, where it is important to maintain safety sightlines and keep plants from falling across paths, consider shorter species. Such plantings will also prevent short plants from being shaded compared to species mixes with a wider range of heights. (In areas where plant height is not an issue, select species over a wider range of heights for greater plant diversity.)

For sunny spots with dry-mesic (medium) soil conditions, a low profile garden that will support bumble bees could include prairie smoke (Geum triflorum), shooting star (Primula meadia), sundial lupine (Lupinus perennis, also called wild lupine), large-flowered beardtongue (Penstemon grandiflorus), downy wood mint (Blephilia ciliata), purple prairie clover (Dalea purpurea), rough blazing star (Liatris aspera), and aromatic aster (Symphyotrichum oblongifolium). Include short grasses like Junegrass (Koeleria macrantha), purple love grass (Eragrostis spectabilis), prairie dropseed (Sporobolus heterolepis), and side-oats grama (Bouteloua curtipendula) among the flowers listed above. The grasses fill in space between plants, physically support other plants, and will help shade out annual weeds.

For a garden with medium height and dry-mesic to mesic soil conditions, suggestions include: Ohio spiderwort (Tradescantia ohiensis), white and purple prairie clovers (Dalea spp.), leadplant (Amorpha canescens), prairie blazing star (Liatris pycnostachya), prairie coreopsis (Coreopsis palmata), butterflyweed (Asclepias tuberosa), whorled milkweed (Asclepias verticillata), wild petunia (Ruellia humilis), and heath aster (Symphyotrichum ericoides). Add short prairie grasses and sun-loving sedges to this planting.

Taller plants to include in a garden with mesic soil conditions: golden Alexanders (Zizia aurea), bee balm (Monarda fistulosa), meadow blazing star (Liatris ligulistylis), wild quinine (Parthenium integrifolium), rattlesnake master (Eryngium yuccifolium), Culver’s root (Veronicastrum virginicum), and mountain mint (Pycnanthemum virginianum). For late-season bloom, include goldenrods and asters. The latest species flowering in the native plant garden are usually showy goldenrod (Solidago speciosa), Riddell’s goldenrod (Oligoneuron riddellii), and New England aster (Symphyotrichum novae-angliae), extending nectar supply at the end of the flight season. Taller grasses and sedges for full sun can serve as the matrix that fills in between the flowering forbs in this planting.

Gardeners often try new plantings and keep track of how plants do in new situations. If you follow guidelines about species’ sun and moisture requirements (i.e., their growing preferences) as you plant, you will learn about both the plants and your site to refine future gardening decisions. Curiosity and observation are great gardening tools.

Many of these species are available at the Friends of the Arboretum online plant sale, which is open until March 31, with pickup at the Arboretum in May. Half and full flats of single species, as well as special garden kits for different types of sites, are available. Feel free to send a gardening question as your garden planning continues.

– Susan Carpenter, native plant garden curator