Why Native Plants Are Taking Over Tennessee Gardens
Native plants let you do things no ornamental can․ They grow in the clay that is all Tennessee‚ tolerating humidity extremes․ There are nectar and pollen sources for co-evolved pollinators and a reduction in your watering and spraying frequency once they are established․ That's the whole case in a nutshell․ The rest of this comes down to which species work where‚ and how to actually get them growing․
Tennessee lies mainly in USDA plant hardiness zones 6a through 7b‚ with Memphis located in zone 8a․ However‚ a plant "native to the eastern United States" may not do well here if it is native only to the sandy Atlantic coastal plain or the heavy clayey loam of the Midwest․ The following plant list has been reliable and successful beyond "native to North America" in Middle and East Tennessee․
Little Bluestem: The Workhorse Grass
Little bluestem (Schizachyrium scoparium) can survive hot summers and cold Tennessee winters․ The grass is blue-green in the early spring and dark green in the summer․ In October‚ the grass turns rusty copper-brown which may last into the winter․ It is one of few native grasses which withstand a hard frost and still remain attractive into most of the winter․ It prefers full sun and fairly well-drained soils‚ but is better suited to average or poorer soil than the heavy soils of most gardens‚ since nitrogen-rich soils induce flopping․
While a spacing of 18-24 inches is recommended‚ it will fill any space given to it in its second year․ Very little maintenance is needed‚ save a low cut to about 4 inches in late February before growth begins․ Being somewhat ornamental and having roots extending a few feet deep‚ the plant is a good choice for slopes or rain gardens․
Blazing Star for Pollinator Traffic
If you want to see monarchs and swallowtails and bumblebees work your yard in real time‚ plant Liatris․ The purple flower spikes bloom top down over three to four weeks in mid to late summer‚ longer than most perennials give you․ Liatris spicata and Liatris aspera grow best in Tennessee‚ though spicata prefers moister soil while aspera prefers drier and rockier soil․
Plant in fall or spring three inches deep in full sun․ First year plants can be slow to appear․ If your plants do not appear above ground the first season‚ don't worry․ The root system will catch up by the next year․ And deer tend not to bother it‚ or at least it's not as common a target as most flowering perennials․
Northern Spicebush: The Understory Shrub No One Notices
Spicebush may have unimpressive flowers‚ but it is certainly one of the most important․ Spicebush flowers‚ which are small and yellow‚ bloom in late March or early April (before the leaves)‚ and provide the very first food of the year for springtime bee species that are emerging from hibernation․ This is the only plant that spicebush swallowtail caterpillars can feed upon‚ and thus should be planted as a host to that butterfly․
Height-wise this shrub ranges from 6 - 12 ft․ It can be grown in partial shade‚ making it a great shrub to grow beneath large canopy trees without the use of mulch․ It will tolerate the wetter‚ heavier soils of creek bottoms or low ground that most shrubs will not․ Once established (in about two years)‚ it requires virtually no water even during dry July in Tennessee․
Ferns for the Shade You Don't Know What to Do With
Every yard in Tennessee has somewhere‚ even the hottest‚ driest‚ shadiest place during summer‚ a place where grass simply will not grow․ The gardener can make something of value out of this neglect spot by planting one or more of the native ferns that need so little care and are more useful than most gardeners suspect․ They stabilize shaded slopes preventing soil erosion and provide food to a number of moth and butterfly caterpillars while creating a microclimate in which salamanders‚ toads and other helpful amphibian life can thrive․
Christmas fern is the most tolerant‚ evergreen and happiest in dryish shade․ Cinnamon and lady fern prefer more constantly moist soil and if the soil dries out more than a day or two‚ they droop dramatically (but usually recover within a day or two)․ Some cultivars are available from TN Nursery for delivery as bare-root plants or as potted plants‚ which grow much faster than seed-grown plants‚ filling the garden in one season instead of up to three․
Butterfly Weed and Milkweed: The Monarch Connection
Butterfly weed (Asclepias tuberosa) is a drought-tolerant milkweed with orange flowers growing in areas where other milkweeds are unable to survive‚ in dry sandy or rocky soils with full baking sun and not much nutrient․ As larvae‚ the caterpillars feed on the leaves and‚ as adults‚ on the nectar․ Monarch butterflies use this plant as a host for their caterpillars‚ as do two other species‚ common milkweed (Asclepias syriaca) and swamp milkweed (Asclepias incarnata)․ A․ incarnata is better in wet sites because it is better adapted to wet feet than the other two․
Due to its long taproot‚ all three species are difficult to transplant to the garden once they reach full size; butterfly weed therefore benefits from being grown from seed or nursery stock where it is to be planted․ It generally takes around three years to reach full size and flower‚ and as a long-lived perennial‚ may outlive the gardener who planted it․
Do this before redesigning your entire yard․
You're not going to rip out an existing landscape to go native‚ so start with a single bed․ A slope that erodes‚ a shaded area or a dry area along your driveway is an ideal place to add a plant that works in that spot‚ rather than the garden․ Try combining a grass such as little bluestem with a bloomer such as blazing star to create contrasting textures and colors‚ as well as a more realistic simulation of natural settings where plants grow in loose drifts․
Check to see if what you are getting is the straight species or a highly selected cultivar․ Many nativars have been selected for double flowers or other colors that have little value to pollinators․ TN Nursery sells straight species stock for most of the above natives․
