On a recent visit to a friend in Kohala Ranch, we talked about installing some fire-resistant plant species. A friend of hers had recommended elephant bush (Portulacaria afra), known in the Afrikaans language as spekboom in its native South Africa. Her friend, Bernard Moret, had written about his experience with this plant for the Kohala Ranch Report and gave me permission use his story here.
A recent fire in Kohala Ranch burned all the ground covers near his house but it was stopped by the elephant bush.
Bernard reported, “(Elephant bush) seems to be under-recognized in Hawaii as a fire-resistant plant; in South Africa, California and Arizona (it) has been used to populate firebreaks.”
I did some additional research and will share what I learned about this plant. For those in fire-prone areas, it is an excellent plant to consider. Elephant bush would also make an interesting addition to a xeriscape garden either potted or in the ground. In a bright location, it can also be grown indoors.
Elephant bush is a succulent shrub in the Didiereaceae family and the Portulacaceae genus. Due to its similar appearance, it is sometimes confused with jade plant (Crassula ovata) but it is not botanically related. It has a more compact growth habit with smaller, rounder leaves and is somewhat hardier than jade plants. It shares more similarities with portulaca plants, thus sharing the same botanical family as moss rose and other portulaca species.
As the name “elephant bush” or “elephant food” suggests, this plant is known to be eaten by elephants as well as other large herbivores including tortoises and the black rhinoceros. Although it is not the primary food source for these animals, it is a significant part of their diet. During periods of drought, elephant bush is often used to feed livestock. It serves as a supplemental source of water in addition to its nutritional benefits.
People also eat this plant. In South Africa it is often used to add a sour flavor to salads, soups or stews. The crispy foliage is slightly tart and contains small amounts of malic acid.
Many features make elephant bush a good firebreak. It is very heat resistant and can withstand the extreme heat of a fire with only slight withering. Also, its small succulent leaves do not burn easily. The succulent woody stems also add to its resistance to fire.
Other features make this plant a good choice for any dry area. Elephant bush is both drought and wind tolerant. It can also withstand the heat and sun of desert conditions once established and has several varieties both prostrate and upright.
Growth habits of the elephant plant range from a low-growing ground cover to a sprawling tree form that can grow over 10 feet tall in ideal growing conditions. Growing in a hot sunny location in soil that drains well, gets sufficient water and adequate fertilization the plant can grow tall and may produce flowers over time.
Elephant bush does well in pots. Some varieties work well in a hanging basket where its trailing stems will cascade down gracefully. Indoors it is a low-maintenance house plant and it is a good specimen to use for bonsai.
Several varieties of elephant bush or spekboom exist. Some occur naturally while others have been bred in cultivation. A good ground cover variety that is resistant to burning is prostrata. A compact upright known as aurea has leaves that turn bright yellow in the sun, giving it the name “yellow rainbow.” Variegata has cream-colored leaves and is well suited to covering slopes or terraces. Cork bark is a variety with a rough stem making it especially prized for bonsai.
Elephant plant is a perennial with a soft woody stem that is reddish when young. and that has small fleshy green leaves that are round and glossy. The leaves grow off the young stems as well as off the older, stiff, tapering branches. The irregularly-arranged branches may need some pruning to prevent them from growing into a thicket. Older, heavy branches can be brittle and may occasionally break off.
Fallen branches often root where they fall, starting new plants. Since flowering and fruiting is rare among elephant plants, the best propagation technique is from cuttings. Remove a stem from the main plant and let it dry and callous for a few days. Once this has occurred, place it on soil that drains well and only water it when the soil is dry. Keep the cutting in a shady spot and it should root in four to six weeks.
Once the plant has rooted and is putting out new leaves, you can plant it in a spot that gets at least six hours of sun a day in soil with good drainage. Water it only when the top of the soil is completely dry. The plant needs little attention. You can fertilize lightly every few months to encourage vigorous growth and flowering.
Pruning is only needed to control the plant’s size and spread.
Elephant plant is not usually attacked by pests. Although it is subject to root rot, this can be prevented by allowing the soil to dry out periodically and never allowing the plant to sit in wet soil.
Flowering is rare in elephant bush in cultivation. Fertilizing can encourage flowering over time. Small white or pink star-shaped blossoms may appear in clusters at the end of succulent stems when the plant is healthy and mature. If the flowers are pollinated, they will produce tiny berry-like dry fruit that contains a single seed. If seeds appear, you may try getting them to germinate but growing new plants from cuttings if far more reliable.
In addition to being an interesting, edible and fire-break plant, Portulacaria afra is often used as a “carbon sponge.” This means it is capable of absorbing high levels of carbon from the air. Carbon absorption and sequestering is a very attractive attribute as we seek to deal with climate change
Call around to find sources of Portulacaria afra. Some nurseries in and around Hilo may carry the plant. Just be sure you get the actual elephant plant and not a different portulaca or a jade plant. Neither of these have the same fire-resistant quality.
Gardening Events
Saturdays:
• “Work Day at Amy Greenwell Garden” from 9 a.m. to 12:30 p.m. Meet at the Garden Visitor Center across from the Manago Hotel in Captain Cook. Come with a mask and prepared to practice social distancing. Volunteers can help with garden maintenance and are invited to bring a brown bag lunch. Water and snacks provided. Visit the website www.amygreenwell.garden/get-involved/volunteer-1/ and sign up for the weekly email for more information on work days.
Farmer Direct Markets
(Check websites for the latest hours and online markets)
Wednesday:
• “Ho‘oulu Farmers Market” 9 a.m. to 2 p.m. at Sheraton Kona Resort &Spa at Keauhou Bay
Saturday:
• “Keauhou Farmers Market” 8 a.m. to 12 noon at Keauhou Shopping Center. Information on their online market: keauhoufarmersmarket.com/onlinemarket
• “Kamuela Farmer’s Market” 7:30 a.m. to 12 noon at Pukalani Stables
• “Waimea Town Market” 7:30 a.m. to noon at the Parker School in central Waimea
• “Waimea Homestead Farmers Market” from 7:30 a.m. to 12 noon at the Waimea middle and elementary school playground
Sunday:
• “Pure Kona Green Market” 9 a.m. to 2 p.m. at Amy Greenwell Garden in Captain Cook
• “Hamakua Harvest” 9 a.m. to 2 p.m. at Hwy 19 and Mamane Street in Honokaa
Plant Advice Lines
Anytime: konamg@hawaii.edu
Tuesdays and Thursdays: 9 a.m. to noon at UH-CES in Kainaliu — (808) 322-4893 or walk in
Mondays, Tuesdays and Fridays: 9 a.m. to 12 noon at UH-CES at Komohana in Hilo — (808) 981-5199 or himga@hawaii.edu
Diana Duff is a plant adviser, educator and consultant living part time in Kailua-Kona.