Covering bare ground in the landscape is essential to preventing erosion and controlling weeds. Although we can choose to cover the ground with mulch or weed cloth or even cardboard, using a plant to cover an open area is the most attractive solution. Selecting a ground cover with lots of positive attributes is a wise decision. Perennial peanut has many desirable characteristics that make it an excellent groundcover choice for Kona gardeners.
Several varieties of perennial peanut are grown here. Arachis pintoi “golden glory” is widely used as a ground cover and to prevent erosion on slopes. It is propagated vegetatively from stolons or cuttings. Arachis pintoi “amarillo” was developed in Australia for animal forage as well as for an ornamental groundcover. Amarillo seed is occasionally available here but it can also be grown from stolons or cuttings. Differences between the two cultivars are slight. The undersides of amarillo leaves are hairy unlike the smooth leaves of golden glory. Golden glory flowers grow on slightly shorter stalks than amarillo. Another species that grows here is Arachis glabrata. It is grown in Florida for animal feed and as a cover crop in orchards. The leaves of this species are somewhat longer and thinner and its flowers are a deeper yellow. This plant produces fewer flowers than the two pintoi cultivars. All of the Arachis species are native to tropical South America and are wild relatives of the cultivated edible peanut.
Perennial peanut plants crawl along the ground but do not twine around other plants or grow up trees. They are useful as legumes that sequester atmospheric nitrogen into their roots. This nitrogen fixing quality means that they can provide nutrition for their own growth as well as for nearby plants. Another positive attribute of perennial peanut is the year round production of attractive yellow flowers. Flushes of flowers will often appear after a rainy period but too much soil moisture can cause leaves to yellow and flowers to drop.
Another positive characteristic of perennial peanut is its ability to tolerate a variety of soil types and the conditions at many elevations from sea level to 5,000 feet. The ideal environment for vigorous growth of this plant is a sunny location in soil that drains well. Though it can tolerate drought, it will sometimes drop leaves in long dry spells. It will return to full health, however, as soon as rain or adequate water is supplied.
Once established, perennial peanut needs little maintenance. Though young seedlings need regular watering to get a good start, mature plants require only occasional watering. The plants can form a thick mat of vegetation, especially when maintained less than 6 inches tall by mowing or weed whacking periodically. Pruning may also be needed occasionally to keep the plant from spreading into unwanted areas. Very few pests attack perennial peanut though young plants can be attacked by slugs and snails. Pet-safe snail bait is a safe and effective way to control of these gastropods.
Perennial peanut has many additional appealing attributes. It covers open soil quickly, protecting it from erosion while helping to retain moisture and encouraging the growth of soil micro-organisms. Its seeds germinate when top growth dies back, enabling it to maintain a dense mat. This ground cover also discourages weeds by shading or crowding areas where they might appear. As a living mulch, it also helps to improve soil structure and health.
You can propagate perennial peanut in several ways. When seeds are available, they can be sown about 1/2-inch deep either directly in the garden or in pots. Germination is usually in less than two weeks but it may take five or six months to establish a uniform cover. Stem cuttings can be partially buried in pots or directly in a garden bed. They should root in less than a month. If planted about 12 inches apart they can create a dense mat in less than six months. Planting the rooted stolons is another way to successfully propagate perennial peanut. Stolons appear as rooted plantlets and should be treated like transplants. Once removed from the mother plant, they should be planted quickly and not allowed to dry out.
Pots and flats of perennial peanut are often available in local nurseries. Call around to find them. Plant the new plants in holes that are the same depth as the pot. Cover the roots but do not bury the plant. Keep the new plants moist until well-established.
With so many positive advantages from planting perennial peanut, it is obviously a good ground cover choice. If you are looking for a multipurpose ground cover, it is the perfect plant for your garden. Call around to find it at local nurseries or look for it growing in nearby landscapes, orchards or farms and ask the owner for a few cuttings. You will likely be delighted with the many benefits of growing perennial peanut plants in your garden.
Diana Duff is a plant adviser, educator and consultant living in a dryland forest north of Kailua-Kona.
Gardening Events
Saturday: “Work Day at Amy Greenwell Garden,” 9 a.m. to 12:30 p.m. Meet at the Garden Visitor Center across from the Manago Hotel in Captain Cook. Volunteers should bring a brown bag lunch. Water and snacks provided. Call Peter at 323-3318 for more information.
Farmer Direct Markets
Wednesday: “Sunset Farmers Market,” 2 p.m. to sunset at the north makai corner of the Kmart parking lot
Wednesday and Friday: “Hooulu Farmers Market,” 9 a.m. to 2 p.m. at Sheraton Kona Resort and Spa
Friday: “Pure Kona Market,” 9 a.m. to 5 p.m. at Amy Greenwell Garden in Captain Cook
Saturday: “Keauhou Farmers Market,” 8 a.m. to noon at Keauhou Shopping Center
“Kamuela Farmer’s Market,” 7 a.m. to noon at Pukalani Stables
Sunday: “Pure Kona Green Market.” 9 a.m. to 2 p.m. at Amy Greenwell Garden in Captain Cook
Tuesday through Saturday: “U-Pick greens and produce,” 10 a.m. to 4 p.m. Tropical Edibles Nursery, Captain Cook.
Plant Advice Lines
Anytime: konamg@ctahr.hawaii.edu
Tuesdays and Thursdays: 9 a.m. to noon at UH-CES in Kainaliu, 322-4892
Mondays, Tuesdays and Fridays: 9 a.m. to noon at UH CES at Komohana in Hilo, 981-5199 or himga@hawaii.edu