The Portulaca genus of plants is in the Portulacaceae family, which includes about 400 species. Forty different species of the Portulaca genus exist throughout tropical and warm temperate locations.
Several grow well here in Kona as attractive groundcovers as well as edible specimens. Two popular members of this family do well in full sun locations at lower elevations. They are also drought tolerant and will happily grow over our ubiquitous rocky soil.
Moss rose (Portulaca grandiflora) grows no higher than 6 inches tall and will fill an area with lots of small, bright-colored flowers that are about 2 inches across. A South American native, it sports reddish, branching stems and small, succulent, cylindrical leaves with pointed tips. Named for the flower’s rose-like shape, a wild assortment of cultivars are available. Both single- and double-flowered strains exist as well as single or mixed colored species with a range of hues from deep pink to bright yellow. Moss rose cultivars come with exotic names like “magic carpet,” “sundance” and a special “sundial” that stays open later in the day and has large double blossoms.
Purslane (Portulaca oleracea) has fleshy oval leaves and bright yellow flowers. This attractive groundcover can grow a bit taller than moss rose, up to about a foot in height. It is a good companion for other plants as its strong taproot breaks up hard soil creating a pathway for weaker roots to use. It is likely native to India and is now established in many places with hot, dry climates including parts of Hawaii.
Known in Hawaiian as akulikuli kula, the botanical name for this portulaca is oleracea, which is a Latin word for “potherb.” The botanical nomenclature relates to the plant’s use in many different dishes throughout India and the Middle East. The stems and leaves can be steamed, pickled or added to salads or soups. The plant’s sap has many medicinal uses and is the richest known plant source of omega-3 acids. Use it as a groundcover until it spreads too far, then pick it and eat it.
A hybrid known as “wildfire” (Portulaca umbraticola) is also well suited to hot, dry areas but a bit harder to find. It produces single flowers and in many bright colors including several bi-color specimens.
Two Portulaca family members are native to Hawaii.
Both Portulaca molokiniensis and Portulaca villosa are endemic species now found throughout our islands but are somewhat rare in the trade. Molokiniensis is named for one of its native habitats on the small horseshoe island of Molokini off the coast of Maui. Known in Hawaiian as ihi, Portulaca molokiniensis has succulent round leaves that cluster around an upright stem. It produces light yellow flowers that appear at the top of the stalk.
Villosa looks very different with fat, fleshy ovate leaves topped by a delicate white flower. Like others in the family these two native Hawaiian portulacas are well adapted to hot, dry sunny spots that get little water.
All of the plants in the Portulaca genus are succulents, all prefer rather dry soil that drains well and most bear brightly colored flowers that open when exposed to sunlight but may close early in the day or remain closed on cloudy days.
Portulacas produce very tiny seeds that can be used for propagation. If the seeds are scattered on a soil bed that is kept damp, they can take up to three months to germinate, however. Cuttings are a much faster way to produce new portulaca plants.
Consistent applications of small amounts of fertilizer and regular light watering, though not necessary, will likely cause vigorous growth in portulacas. If the plant grows out of bounds, the cuttings can be used to start new plants. Cuttings about 4 inches long inserted in a light mix of perlite and vermiculite and watered every other day should root within two weeks.
Most portulacas can be grown in rock gardens, as simple ground covers or as bedding plants. They can be used as border plants and will do well in containers or hanging baskets. They grow best at elevations below 1,000 feet and are salt-tolerant enough to grow near the ocean. Portulacas are very susceptible to root rot if the soil remains wet for long but can easily be propagated to make more plants if you lose a few.
These plants are unlikely to be attacked by insects or diseases if planted in the proper place and minimally maintained.
Both grandiflora and wildflower are widely available in nursery departments. The yellow-flowered edible purslanes are a bit harder to find but Tropical Edibles Nursery in Captain Cook does carry them.
Considering the ever blooming characteristic of portulacas, their drought tolerance and the minimal care needed to grow them, they are highly recommended as an addition to any Kona garden.
Diana Duff is a plant adviser, educator and consultant living in a dryland forest north of Kailua-Kona.
Gardening Events
Thursday: “Little Fire Ants – Informational Meeting” from 6-7 p.m. at the Honalo Marshaling Yard at 79-1017 E Honalo Road (just south and across Highway 11 from Higashihara Park). The Hawaii Ant Lab will present information on ways to prevent, detect and treat LFA.
Saturday: “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. Volunteers will be able to help with garden maintenance and are invited to bring a brown bag lunch. Water and snacks provided. Call Peter at 323-3318 for more information.
Farmer Direct Markets
Wednesday: Hooulu 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 noon at Keauhou Shopping Center
Kamuela Farmer’s Market from 7 a.m. to noon at Pukalani Stables
Waimea Town Market from 7:30 a.m. to noon at the Parker School in central Waimea
Waimea Homestead Farmers Market from 7 a.m. to noon next to Thelma Parker Gym in front of Thelma Parker Library.
Sunday: Pure Kona Green Market 9 a.m. to 2 p.m. at Amy Greenwell Garden in Captain Cook
Hamakua Harvest 9 a.m. – 2 p.m. at Hwy 19 and Mamane Street in Honokaa
Plant Advice Lines Anytime: konamg@ctahr.hawaii.edu Tuesdays &Thursdays: 9 a.m. to noon at UH-CES in Kainaliu – 322-4892
Monday, Tuesday and Friday: 9 a.m. to noon at UH CES at Komohana in Hilo 981-5199 or himga@hawaii.edu