Sometimes known as “cabbage on a stick,” the native Hawaiian alula is a very unusual species. It is endemic to Kaua’i and Ni’ihau, but currently endangered in the wild. Through authorized propagation from cultivated plants alula is now available throughout the world as an interesting house plant or as curious specimen in a tropical garden. It might be time to include this species in your native Hawaiian plant collection.
Those interested in xeriscape gardening will definitely like alula’s drought tolerance. It needs to be grown in soil that drains very well and actually does best in a clay pot that is only occasionally watered. Clustered in a large pot it makes a very interesting display for a lanai or in a bright spot indoors or out.
Alula’s somewhat prehistoric appearance adds to its appeal. It grows as a fat, succulent stalk that is thicker at the base and sometimes branched. Though usually between 2 and 6 feet tall, older specimens can reach ten feet. The crown is seldom more than two or three feet across.
The spoon shaped, leathery, light green leaves grow in a rosette pattern at the top of the stalk. Yellow flowers emerge from between the leaves on 2-inch tubes often in late summer or early fall. The fragrant trumpet-shaped flowers are a little over an inch across. When in full bloom, the blossoms encircle the top of the plant appearing like a crown.
Alula is in the Bellflower (Capanulaceae) family which has over 2,000 species most of which are in the Lobelia genus. Two family members are in the Brighamia genus and both are native to Hawaii. The genus name honors William Tufts Brigham who was the first director of the Bishop Museum in Honolulu.
Alula is known botanically as Brighamia insignis. In Latin insignis means outstanding, remarkable or distinguished. All of these descriptions aptly describe this plant’s unique appearance. Its close relative Brighamia rockii, known as pua’ala is native to Molokai and has a similar appearance but with smaller leaves and a white flower. Both natives grow on rocky outcroppings including high exposed sea cliffs like those on the Na Pali coast of Kaua’i.
When the brighamia pollinators became extinct, efforts were taken by scientists to hand pollinate the remaining plants which were growing high on cliffs above the ocean where hungry feral goats could not reach them. The project in 1970 succeeded in producing seed pods and the seeds were successfully grown out to produce plants that have been shared with nurseries around the world.
Alula does not grow from cuttings but seeds can be collected from pods that form following pollinated flowers. Seedlings sometimes flower in their first year, but can take as long as three years to bloom. For reliable seed production, hand pollination of the flowers is recommended.
When the flowers have been opened for a few days, they will begin to shed pollen. The stigma of a receptive flower is ready to receive pollen when it appears shiny and sticky. With a paint brush, you can pick up fallen pollen from one flower and apply it to the stigma of another flower. Pollination is successful, if the base of the pollinated flower begins to swell in a few days.
Within six to eight weeks, a green capsule will form as the flower fades. When mature, the capsule will crack open releasing many small, smooth seeds. Though the sticky sap in the fruit will cause some seeds to stick on the capsule, harvesting and bagging the entire capsules will save the most seeds. For best results plant the seeds when they are fresh.
Hasten germination by sprinkling the seeds on the surface of a moist, fine textured medium that drains well like a fine perlite or a peat and perlite potting mix. Keep the seeding trays in partial shade. Cover the seeds lightly with the soil mix and mist the medium to keep it moist. Most of the seeds should germinate at about the same time, in a few weeks, though some may take a few months.
Once the seedlings have sprouted, you can foliar feed with a light solution. When they are between a half inch and a full inch tall, transplant individual seedlings into tiny pots. Be sure the potting mix drains well. A mix that is three parts fine black cinder or perlite with one part potting mix plus a little bit of a balanced fertilizer will work. Keep them in these small pots in a shaded area for a few months only watering when dry.
Up-pot into 4-inch pots after about 3 months and continue repotting about every six months into new soil and larger pots. Gradually expose the plants to more sun before putting them in their final pot or location in a sunny spot.
Alula will thrive in full sun as well as a bright spot in partial shade. Treat the alula like a succulent. It needs a well-aerated soil mix, a little fertilizer and occasional watering.
Keeping the soil relatively dry, will also help the plants remain healthy. Overwatering can cause root rot which is the most common disease in alula plants. Leaf spot fungus is also caused by overwatering or an overly moist environment for this plant.
Foliar feeding every few months or applications of a slow-release fertilizer every six months will help your alula plants thrive. Applying a fertilizer with high phosphorus may help encourage flowering.
Slugs and snails love alula. Put out slug bait or traps to avoid the disappointment of losing your precious seedlings to hungry mollusks. Large African snails can destroy a mature plant overnight.
Though alula are definitely more available these days, you can avoid the search by going to the plant sale at Amy B.H. Greenwell Ethnobotanical Garden in Captain Cook. Their upcoming sale will feature Alula with many available for sale. The sale is on Saturday and Sunday, July 9 and 10 from 9 a.m. to noon. Don’t miss this sale to stock up on Hawaiian native plants including alula.
This article was reviewed for accuracy by Peter VanDyke from Amy B.H. Greenwell Ethnobotanical Garden.
Diana Duff is a plant adviser, educator and consultant living part time in Kailua-Kona.
Gardening Events
Saturday & Sunday: “Native Hawaiian Plant Sale” from 9 a.m. to noon at Amy Greenwell Garden in Captain Cook. Parking at the visitor center at 82-6160 Hawaii Belt Road, across from the Manago Hotel. Hundreds of native plants will be available for sale including the rare and beautiful alula. Admission is free.
Saturdays, July 9 & 16: “Hawaii Macadamia Nut Association Conference & Field Day” Conference on 7/9 from 8:30 a.m. to 3 p.m. at the Hilton Waikoloa Village. $54.67 for non-members, free to members. To register go to https://www.eventbrite.com/e/hawaii-macadamia-annual-meeting-and-conference-tickets-322890994657.
July 16: “Healthy Soil, Healthy Orchard field day” 9 a.m. to noon at Island Harvest farm in Kapaau. For more information or to buy $5 tickets, visit https://www.eventbrite.com/e/healthy-soil-healthy-orchard-from-planning-to-practices-tickets-333108756257.
Plant Advice Lines
Anytime: konamg@ctahr.hawaii.edu; Tuesdays and Thursdays from 9 a.m. to noon at UH-CES in Kainaliu at (808) 322-4893. Walk-in from 9 a.m. to noon Mondays, Tuesdays, and Fridays at the UH-CES at Komohana in Hilo or call (808) 981-5199 or email himga@hawaii.edu