The Genus Arachis
This is a medium-sized genus of herbaceous perennials from South America. One species, Arachis hypogaea, is the edible peanut. With the help of colonies of bacteria in nodules on their roots, these plants capture atmospheric nitrogen and are able to grow well in infertile soils.
The bean family, Fabaceae, is one of the largest of the plant families. It is characterized by seed pods that are known to botanists as legumes. This is a large family that includes many important economic crop genera, including peanut (Arachis,) soybean (Glycine,) alfalfa (Medicago) and beans (Phaseolus.) Ornamental garden plants include orchid tree (Bauhinia,) redbud (Cercis,) coral tree (Erythrina,) lupine (Lupinus) and black locust (Robinia.)
This is a semi-evergreen herbaceous perennial to about nine inches tall that can spread rapidly by underground rhizomes. Small, orange-yellow flowers stand above the dark green foliage. The flowers actually taste like peanuts. It tolerates frequent mowing and is robust enough to substitute for turf in low traffic areas. It grows well in sun to part sun, in a reasonably moist, well-drained soil and is reported to be salt tolerant. Once established, it is drought tolerant. It is cold hardy to at least zone 8b. Some have reported success into zone 7b. It is evergreen further south but dies to the ground when winter tempratures drop below freezing. That is most winters in my northern 9a garden.
This plant is uncommon in local nurseries but may be found in specialty nurseries. Cultivar ‘Needlepoint’ is a small, comparatively slow grower that is suitable for smaller spaces. ‘Ecoturf’ is a more vigorous, taller cultivar that may be a turf substitute in areas with light foot traffic. It remains dark green during summer droughts when Bahia grass struggles. Plants are easily propagated by division.
My plants die back at about 30 degrees F and emerge again in spring around mid- to late March. Flowers appear from late March through November. I use it as a groundcover under my fruit trees and shrubs.
Arachis pintoi ‘Golden Glory’ (sometimes sold as A. repens)
This is a herbaceous perennial to about six inches tall. It spreads by above ground stolons, more slowly than A. glabrata. For this reason, it may serve better as a garden groundcover than as a turf substitute. Or, let it grow into open turf to fill problem areas. Small, light yellow flowers stand above the foliage. In my garden, it produces more flowers than A. glabrata. It grows well in sun or shade, in a reasonably moist, well-drained soil. Once established, it is drought tolerant in the Coastal Southeast. It is reported to be cold hardy to at least zone 8b but is deciduous there in winter.
This is the peanut that I encounter most often in local nurseries. It is sold sometimes as Arachis repens. Plants are propagated by cuttings and division.
My plants spread more slowly than A. glabrata and show drought stress sooner. A few stems root and start new crowns each year. The plants die back to their crowns with a freeze, usually in November or December. Plants resprout in mid- to late March. Light yellow flowers are produced from early April to November.