(Diospyros sandwicensis) – A Common Curiosity

    Lama, Diospyros sandwicensis in particular, puzzles me. This is a tree that often dominates dry forests here on O‘ahu as well as on the other Islands; some forests in Nānākuli Valley are nearly monotypic stands of lama. And yet, with the exception that it produces a lot of seed when mature, lama seems to have none of the obvious characteristics that would lead you to believe it would be so successful. While abundantly produced, lama seeds are recalcitrant. In other words, the seeds are short-lived and, therefore, do not remain long in the forest soil seedbank. The seedlings can be killed by at least one particularly nasty fungus, and are not immune to death via insect pests such as scale insects. But, what is most puzzling is how such an incredibly slow-growing tree can come to dominate a forest. Lama seedlings grow slow – very slow. In the dry forest, it’s not unusual to see a lama seedling add only two or three new leaves a year. And, this can go on for years. In cultivation, the story is only slightly different. Yes, lama seedlings grow faster in the nursery, particularly when they are frequently fertilized, but they still grow slower than nearly any other dry forest plant. In addition, unlike some other dry forest trees such as kauila or uhiuhi that begin to flower and fruit after only a couple of years out of the nursery and in the ground, lama takes a long time to mature; five years under cultivation, perhaps, ten or more in the wild. So, what makes this tree such a winner in the wild? Well, there are only two things I can point to in addition to the previously-mentioned abundant seed. First, lama seedlings grow an incredibly deep taproot. It’s not unusual for a two-inch tall lama seedling to have a six-inch deep taproot. This most likely gives them the ability to survive serious droughts at even this young age; surviving when other dry forest tree seedlings perish. Second, lama trees are tough. While numerous pests do attack lama, once they reach two or three feet in height, they are remarkably resilient. 

(Top to Bottom) Wild lama seedlings at least three-years-old. Ripe lama fruit (photograph courtesy of Amy Tsuneyoshi). New lama leaves.
Habitat & Appearance: Diospyros sandwicensis is a small to medium size (6 - 30 feet tall) tree most often growing in dry open or closed canopy forest but also present in mesic and, occasionally, in wet forest. It is endemic to all the main Hawaiian Islands except Ni‘ihau and Kaho‘olawe. Lama bark is normally black or gray with the main trunk being relatively smooth while very old trees have a trunk with deep furrows or flaky bark. Leaves are dull grayish green, arranged alternately on the stem all in a single plane. New leaves are a striking red. Lama flowers are unisexual (i.e., pollen producing or fruit producing). The fruit is ½ - 1 inch long, turning from green to yellow, orange or red when mature. Lama are often infested with a very small mite that causes the tree to produce finely branched growths on the branches. 
Lama in Hawaiian Culture: Lama, like many Hawaiian words, has multiple meanings. Lama is the name Hawaiians gave to two closely related species of endemic trees, Diospyros sandwicensis and D. hillebrandii. Lama also means torch, light and flame. As in English, this meaning was extended to suggested enlightenment, as in the learning of hula. In ancient times, a block of lama wood wrapped in scented yellow kapa was placed on a kuahu (altar); the lama wood embodied Laka, the goddess of hula. The sick were placed in a hale (house) constructed in the daylight hours of a single day from lama wood to be cured. Lama wood was also used to erect fences around sacred places. A poultice for skin sores was made of pulverized lama wood and other ingredients. Fish traps were sometimes made from lama branches. Hawaiians ate the slightly astringent ripe lama fruit after drying; lama is related to persimmon.      
Collecting Seeds: Lama normally flower and fruit once a year. In my experience (mostly on O‘ahu), lama fruits ripen during the winter or early spring. The ripe fruits are soft, and can be red, orange or yellow. Inside, there can be anywhere from one to four light brown seeds (1-2 seeds per fruit is most common). While seeds directly from the tree are preferable, being cleaner and less likely damaged by insects, etc., you can often collect abundant lama seeds from the ground. Back at the nursery, remove the seeds from their fruit and wash thoroughly. Sterilize the seeds by soaking in 10% bleach for 10-15 minutes; this is particularly important for any seeds collected from the ground.  
Growing from Seed: Lama seeds cannot be stored for more than a few months and remain viable, therefore, you should sow your newly-collected seeds as soon as possible. I have used both Method One and Method Two to germinate lama seed. However, if you choose Method One, be sure to quickly transplant the seedlings to deeper containers before their taproots bottom-out within the vermiculite-filled tray. Lama seeds sprout in about a month with the stiff black root emerging from the pointed end of the seed. A nasty damping-off fungus often infects new seedlings, sometimes even before they shed their seedcoat; this fungus can kill a seedling in a single day. Therefore, as a preventative treatment, I paint the seedling’s stem with a sulfur paste using a cotton swab. Sometimes the seedling’s cotyledons has a difficult time shedding the seedcoat. Avoid the temptation to manually help the seedling because you can easily damage the cotyledons or accidentally “tear its head off.” Rather, a gentle misting once or twice a day seems to help the cotyledons break free and throw-off the seedcoat. Once the lama seedling has produced its first true leaf, I normally try to accelerate its growth by applying a controlled-release or standard liquid fertilizer. Scale insects often infest seedlings and young plants. Eliminate them by hand or with horticultural oil. With their long taproot, lama are unsuitable as longterm container plants; once it reaches six or more inches tall, outplant your lama seedling into the garden or restoration site.
Growing from Cuttings: I have never grown lama from cuttings. I don’t know of anyone who has tried.
Growth in the Garden: I wish I had more experience with lama in a garden setting; nearly all my insights come from lama I’ve outplanted into restoration sites. Outplanted without care in a restoration site, lama grow very slowly for the first two to three years, barely reaching a foot in height. Underground, I am certain (because of my autopsies of dead lama) the small plants are diverting nearly all their energy to root growth; a one foot tall lama can have a 2-3 foot deep taproot. During these early years, I have lost about half the lama I’ve outplanted. While a few died from infestations of root mealybugs, most died during the hot dry summer from, I believe, lack of water. What was frustrating was the plants showed little or no signs of drought stress. One day they looked fine; a week later they were brown and dead. Translating this experience to the garden, my advice is to regularly water your lama for the first one to two years. However, remember, this is primarily a dry forest tree. So, regularly translates to no more than once-a-week watering. After lama reach about two feet in height, I have found them remarkably resilient. Their leaves continue to be chewed upon by Chinese rose beetles and grasshoppers but they slowly grow about one foot taller each year. After five years in the ground, perhaps sooner in a garden setting, lama begin to flower and may set fruit. Lama are dioecious (separate pollen-producing and fruit-producing trees), although there may be trees that have both female and male flowers; I just haven’t seen them. Therefore, if your goal is to have a lama tree loaded with colorful (and edible) fruit, you’ll need to plant more than one lama in your garden and be lucky enough to have at least one male tree and one female tree.  
Diseases & Pests: As previously mentioned, lama can be attacked by a small eriophyid mite that causes the tree to produce finely branched growths on the branches. However, I have yet to see this happen to a cultivated tree. While watering a young lama is likely beneficial, watering more mature trees is probably not. Except during drought, watering an older lama will increase the chances a soil fungus or bacterial disease will attack and kill your tree. Watch for root mealybugs, usually accompanied by ants, on young lama. Drench the roots with a horticultural oil and systemic insecticide mix to eliminate the mealybugs. Chinese rose beetles and other chewing insects will periodically disfigure lama leaves. (Lama leaves are long-lived, so, this damage is more noticeable than on plants with short-life leaves.) Refer to Enemies in the Garden for ways to deal with Chinese rose beetles. 

Ā ā  Ē ē  Ī ī  Ō ō  Ū ū