Lignum vitae is an attractive member of the small Zygophyllaceae family. Surprisingly, this “wood of life” tree is underused in local landscapes mostly because of its slow growth habit. This slow growth and its small size at maturity can be seen as an advantage, however, for people with limited space.
Several other characteristics of this tree in the Guaiacum genus make it an ideal choice for Kona gardeners. Since it grows slowly it seldom needs pruning and slow growth makes its wood very hard and fairly resistant to diseases. Additionally, this tree is tolerant of poor soil, dry conditions and even some wind and salt stress. It is a perfect choice for the hot, dry climate at lower elevations.
In addition to its tolerance for a variety of growing conditions, lignum vitae trees also have many visually attractive features. The tree produces clusters of lavender-blue flowers almost year round that are followed by small heart shaped yellow fruit that split to reveal a red aril or seed covering. The bark on mature specimens adds to the colorful display with its gray-brown bark that peels off in spots exposing patches of the light green layer below.
Another member of the Zygophyllaceae or Creosote bush family is the native nohu (Tribulus cistoides), which is a low growing shrub with spiny fruit. Of the Zygophyllaceae family members that grow here, the native shrub known as puncture vine probably has more similarities to other members of the family, than the lignum vitae trees.
Two very similar trees in the genus Guaiacum grow well here. Guaiacum officinale, the true lignum vitae is native to the West Indies and Central America. It is the national tree of the Bahamas and its blue flower is the national flower of Jamaica. Her close cousin, Gauiacum sanctum, is a somewhat smaller tree native to the Florida Keys, some Caribbean islands and parts of Central America. The smaller tree is known as holy wood lignum vitae.
Both trees are known for their very hard wood. It is so dense that it doesn’t float in water. Its hardness, durability and strength made it an ideal choice in ship building as well as for fine furniture, croquet balls, judges’ mallets and other items where density was an advantage. Some of the wood’s former uses now rely on heavy duty plastics and polymers, however.
The “wood of life” and “tree of life” names were attached to lignum vitae trees mostly because of their widespread use in herbal medicine. The leaves, flowers, inner bark and wood of the trees have medicinal uses that were developed and remain important where the trees are native. Its volatile oils, resins and lignans are used in treating a variety of ailments. A tonic tea can also be made from lignum vitae wood chips. Add these uses to the usefulness of its hard wood and the life-giving moniker makes perfect sense.
Today, in Hawaii, these trees are mostly used ornamentally. They make excellent shade trees and are good at screening an area. Both can grow well in pots and make lovely bonsai specimens. They can be maintained as a multi-trunked shrub between 5- and 10-feet tall or allowed to grow as a specimen plant that can reach nearly 25 feet at full maturity. They have a spreading growth habit and can get nearly as wide as they are tall. Easily pruned when young, you can determine its size and shape early in its life.
Lignum vitae trees produce their lavender blue flowers nearly year round here. Following flowering the color show continues as the heart shaped fruit or seed pods turn from green to yellow and orange then spit to reveal two seeds in a red covering. Inside the covering are small dark brown seeds that can be used to propagate more trees.
Once the fruit is orange you can remove the seeds. After removing the red covering, rub the seeds on a cloth and rise well to remove all the pulp. The seeds only remain viable for about a month so they should be planted soon after harvest. Start each seed in a small pot filled with equal parts of vermiculite and perlite or a good seeding mix. Keep them a bit moist, damp but not wet, and they should send up seed shoots within two weeks. Once they are about a foot tall, which can take about a year and a half, you can plant them in a larger pot or out into your garden. Fertilize and water lightly during their early, I did say slow, growth period.
Propagation from semi-hardwood cuttings is possible but may take a long time. If you don’t have access to a flowering and fruiting tree, you can order seeds online.
Once your new trees are ready to plant out, choose a site in full sun or partial shade. These trees can tolerate a variety of conditions as long as the soil drains well.
They can be a nice addition to a xeriscape garden as they need very little water and almost no other care or maintenance. You can prune to shape your plants. Their slow growth means they will not quickly lose their shape and require frequent attention. As with most plants, lignum vitae will appreciate light fertilization a few times a year.
Lignum vitae wood was very sought after for many years, which took a toll on the species in the wild. Today, thorough replanting efforts, it is becoming more plentiful. To participate in increasing its numbers and to grace your garden with a “tree of life,” consider finding and planting one or more lignum vitae on your property.
Though the trees are not readily available, you can certainly grow your own or check with local nurseries or nursery departments to see if they have them. Margo of Sunrise Nursery may be able to help in your search. Give her a call at 640-9191 if you want to start with a potted tree.
Diana Duff is a plant adviser, educator and consultant living in a dryland forest north of Kailua-Kona.
Gardening Events
Tuesday: “Growing and Cooking with Herbs” 5:30-6:30 p.m. at Kailua-Kona Public Library at 75-138 Hualalai Road Kailua-Kona. Learn ways to grow and use herbs from speaker Nancy McNeal. Info: Call 327-4327
Friday: “Mother’s Day Orchid Show and Sale” 9 a.m. to 6 p.m. at Old Kona Airport Park Pavilion. Sponsored by Kona Orchid Society. Featuring orchids, tropical plants and crafts as well as educational speakers. Info: Visit http://www.konaorchidsociety.org/our-annual-show-and-sale.
Saturday: “Mother’s Day Orchid Show and Sale” continues 8 a.m. to 4 p.m. at Old Kona Airport Park Pavilion. Info: Visit http://www.konaorchidsociety.org/our-annual-show-and-sale.
“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. Info: Call Peter at 323-3318.
Farmer Direct Markets
Wednesday: “Hooulu Farmers Market” 9 a.m. to 2 p.m. at Sheraton Kona Resort &Spa at Keauhou Bay
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” from 7 a.m. to noon at Pukalani Stables
Sunday: “Pure Kona Green Market” 9 a.m. – 2 p.m. at Amy Greenwell Garden in Captain Cook
Tuesday–Saturday: “U-Pick greens and produce” 10a.m. to 4p.m. Tropical Edibles Nursery, Captain Cook.
Plant Advice Lines
Anytime: konamg@ctahr.hawaii.edu Tuesdays &Thursdays: 9 a.m. to noon at UH-CES in Kainaliu – 322-4892
Mon., Tues. &Fri: 9 a.m. to noon at UH CES at Komohana in Hilo 981-5199 or himga@hawaii.edu