687 Guajacum sanctumCommon Names: holywood lignum-vitae, lignum-vitae, tree-of-life Family: Zygophyllaceae (caltrop Family)
Holywood lignum-vitae is a handsome large shrub or small tree with shiny evergreen leaves, fissured light gray bark, and the bluest flowers you will ever see on a tree. The tree can get up to 30 ft (9.1 m) tall, but usually is around 15 ft (4.6 m) tall. The 4 in (10.2 cm) leaves are pinnately compound, and borne in opposing pairs originating from swollen nodes along the slender, crooked, somewhat drooping branches. Each leaf has 2-5 pairs of 1.5 in (3.8 cm) oblong leaflets, and each leaflet has a tiny apical tooth. An unusual characteristic of lignum-vitae is that the pairs of leaves are held in the same plane; most plants with opposite leaves hold them at right angles to each other. Flowers are produced at the tips of shoots singly or in few-flowered clusters during March and April. The flowers are almost 1 in (2.5 cm) across and the petals are true blue (a real rarity). The fruit is a brown 5-lobed capsule that splits open when ripe in September or October to expose black seeds that are enclosed in a fleshy red pulp.
Holywood lignum-vitae, Guajacum sanctum, occurs naturally (but uncommonly) in dry coastal areas throughout the Caribbean basin including the Bahamas, West Indies, Yucatan, Central America, and in the middle and upper Florida Keys. Holywood lignum-vitae was once common on the lower Florida Keys and Key West, but it was completely exterminated there by over harvesting for its valuable wood. Today the species is very rare in Florida and only a few specimens remain. Holywood lignum-vitae is listed as an Endangered species by the State of Florida. Best place in the US to see holywood lignum-vitae is at Lignumvitae Key State Botanical Site on Islamorada.
CultureLight: Full sun to light shade. Moisture: Lignum-vitae is drought tolerant and requires a soil with excellent drainage. Hardiness: USDA Zones 10 - 11. Propagation: By seed or by new-growth tip cuttings in spring. Seeds are difficult to germinate because (like many tropical trees) lignum-vitae seeds have a natural tendency to remain dormant for a long time. Germination can be hastened by soaking the seeds in a 0.1% solution of gibberellic acid.
Use lignum-vitae in tropical seaside settings. It is resistant to salt spray and tolerant of drought, so would be a good choice for dry, sandy soils near the coast. Lignum-vitae makes a handsome specimen or, used in groups, an effective hedge. It grows very slowly, so don't use lignum-vitae if you want a quick screen! Lignum-vitae also is grown in containers, where it will stay small for many years.
There are six species of lignum-vitae, all native to dry tropical forests in the New World, and all rather similar in most characteristics. Lignum-vitae is the national tree of the Bahamas and the flower is the national flower of Jamaica. Texas lignum-vitae (G. angustifolium) occurs in the Rio Grande valley.
Lignum-vitae has the hardest wood of any commercially harvested tree. The wood is yellowish or greenish brown and has a resin content of about 30% by weight. Lignum-vitae wood is exceedingly heavy (it will not float), close grained and split resistant, and is valued for propeller shaft bushings, machine parts, and other applications in which its natural resins make it self lubricating. Lignum-vitae also is the source of gum guaiacum, a resin once used in the treatment of syphilis and arthritis. The common name refers to its supposed holy and life giving properties. There are about 250 species in the family, many of which are typical of deserts, such as the creosote bush (Larrea divaricata).
Steve Christman 5/8/00; updated 5/15/04, 8/18/06