Native Hawaiian Garden (7722)

Hala pepe (Dracaena forbesii; formerly Pleomele forbesii) – The littlest thing

It’s unfortunate that Hawai‘i’s native plants evolved in such a benign biotic environment. Many voracious herbivores, large and small and common elsewhere, never colonized our remote Islands. Had they, Hawaiian plants would likely have adapted to these threatening animals by producing toxic or bad-tasting chemicals within their delicate tissues (or by producing defensive structures such as spines and prickles). But there was no need – until we arrived. Humans have either intentionally (e.g., cattle, pigs, goats) or unintentionally (e.g., rats, slugs, cockroaches) introduced hundreds of alien herbivores to Hawai‘i; many today are naturalized (now exist in Hawai‘i as wild populations without the need of human care). I belabor this observation because it sometimes takes years and just the right circumstances for a native plant (or animal) to cross paths with its most lethal alien foe. Such was the case with our plantings of hala pepe within the Nānākuli Valley Cultural & Botanical Preserve. Wild hala pepe still grow (and, perhaps, still reproduce) in the very mauka gulches of Nānākuli Valley. And, from our first 2005 hala pepe plantings in the Preserve to 2015, most of the plants did well in their new home, growing to nearly five feet in height (but not yet flowering). Only then, during an unseasonable dry winter, and only nearest Nānākuli stream (a nearly always dry stream but the wettest place within the Preserve), did I observe missing patches of bark on several hala pepe; some plants were completely devoid of bark from their base to within inches of their leafy crown. While I never actually saw the monsters eating the hala pepe, I concluded they were most likely alien snails migrating each night from beneath moist rocks in the stream bed. To stop their midnight snacking, I installed wire mesh tubes with copper stripping around the trucks of nearly all the hala pepe within the Preserve. This worked. However, nearly half the hala pepe were so severely damaged they never recovered and were dead within six months. Today (2016), there are still hala pepe growing within the Preserve, but it saddens me every time to see each surrounded by a shiny metal tube.

Habitat & Appearance: Dracaena forbesii is endemic to O‘ahu, most commonly growing in the dry forests (and, less commonly in diverse mesic forests) of the Wai‘anae Mountains. However, it is also reported from the Ko‘olau Mountains. Nearly all the other main Hawaiian Islands have their own endemic hala pepe (i.e., D. aurea on Kaua‘i, D. auwahiensis on Moloka‘i and Maui, D. fernaldii on Lāna‘i, D. hawaiiensis on Hawai‘i); O‘ahu has a second species, D. halapepe. The federal government recently listed D. forbesii as endangered. Hala pepe looks a lot like many of the alien ornamental Dracaena (dragon tree) found in garden shops, with its long sparsely-branched truck and strap-shaped leaves. D. forbesii is one of the smaller hala pepe, usually no more than 20 feet tall, and often with multiple main branches emerging from the plant’s base. The yellow flowers are clustered on a terminal stalk that curves down under the crown of leaves. The fruits look like a cluster of grapes or cherries turning green to red as they ripen.

Ripe fruits of Dracaena auwahiensis (Photograph courtesy of Forest & Kim Starr CC BY 2.0). Seedlings. Five-year-old plant. Header photograph courtesy of J.K. Obata via G.D. Carr ©.

Hala pepe in Hawaiian Culture: Hawaiians obviously recognized the physical similarity of the endemic hala pepe to the indigenous and familiar hala (Pandanus tectorius), but also noted that hala pepe leaves, and usually the plant in general, were smaller (pepe) than hala. Hala pepe bark, roots and leaves, mixed with other plant parts, were used medicinally for various ailments such as fever and asthma (Chun 1994). The soft wood was carved into idols (Lamb 1981), while the flowers were used for lei (Krauss 1993). Within hālau hula, a branch of hala pepe was traditionally placed on the kuahu (altar) to represent the goddess Kapo (Abbott 1992).

Collecting Seeds: Dracaena forbesii flower during the winter and spring. During the summer and fall, the green fruits become reddish brown to red and soft as they ripen. Within each fruit are one to three yellow-white seeds about ⅓ inch in diameter. Whenever possible, collect the fruits as they ripen. Seeds extracted from unripe fruit tend to rot rather than sprout. However, you can cut off a stalk of unripe (but full-size) fruits, take it home, place the cut base in a cup of water, and wait for the fruits to ripen. Recut the stalk’s base and replace the water every few days to prevent water-loving fungi from attacking the stalk and preventing water flow upward to the fruits. Hala pepe seeds have a high water content and do not store well; sowing them soon after collection and cleaning is best. If you must store seeds, my best method to date is letting the fruits ripen and dry on the stalk, and then storing the dried fruits at room temperature; this will extend the viability of the seeds by a few months.

Growing from Seed: Using Method One, hala pepe seeds take two to six weeks to sprout. Curiously, the seedlings have two primary roots. One root is fairly typical in appearance with frequent branching. However, the second root is green near the seed and white deeper into the media. It is also thicker than the other primary root and has few branches. My guess is this second root may be a water and/or nutrient storage organ. The seedlings grow quite rapidly and should be transplanted to individual pots after they have two or three pairs of leaves. After transplanting, they will continue to grow at a good pace, and you should have a 6 to 10-inch tall plant in about six months. A controlled-release or dilute liquid fertilizer will help during this period, particularly, in keeping more green leaves on the trunk. Do not overwater your young hala pepe (remember where they live in the wild). And, if possible, avoid wetting the leaves during each watering; these plants do not like overhead sprinklers. Constant wetting of the leaves causes them to spot, yellow, and fall off prematurely. In extreme situations, the entire crown will die, and the hala pepe (if you’re lucky) will have to sprout a new side branch. While I’ve never sent the spotted leaves out to be diagnosed, I suspect the cause is a fungal disease, possibly Fusarium leaf spot which is known to infect Dracaena. If your garden is relatively free of snails, slugs, rats and mice, it’s safe to plant out your new hala pepe when it's about 10 to 12 inches tall. If these pests are present, or you just want to be extra safe, wait until your plant is 18 to 24 inches tall before you move it to your garden.

Growing from Cuttings: I generally avoid propagating hala pepe from cuttings because each cutting is a significant loss to a parent plant. However, hala pepe have brittle stems and accidents happen. So, whenever a windstorm or careless hands break a branch away from a mature plant, I will try to make a new plant from the broken branch. I have only tried to root cuttings with a terminal crown of leaves, and have never cut a stem up to make multiple leafless cuttings; I’d be very surprised if anyone was successful rooting a hala pepe cutting without a terminal bud. I’ve had better success with Method One than Method Two because of the leaf-spotting and rot associated with constantly wet leaves and stems. For media, I’ve only used a perlite-vermiculite mix (predominately perlite); I fear any organic in the media such as peat moss would likely encourage stem rot. The time it takes a cutting to root varies anywhere from a little over a month to about six months. This variability is probably due to the initial condition of the cutting (e.g., How long was it on the ground after a windstorm before I noticed it?). Once the cutting has rooted, I haven’t noticed any difference in its vigor or survivability compared to a plant grown from seed.

Growth in the Garden: Plant your hala pepe in a site with full sun and good drainage. Often, you will see little or no growth for weeks or months after planting out the hala pepe. Be patient and don’t overreact with excess watering or fertilizers. In fact, the number one killer I’ve seen of this species (and Dracaena hawaiiensis but not D. halapepe) is overwatering. The overly wet soil promotes root rot as well as rotting at the truck base. Eventually, your hala pepe will resume growth, but, unfortunately, it’s not a fast grower. Expect the plant to increase in height 6 to 12 inches per year. Growth occurs in spurts, mostly during the winter. Fertilizing during these spurts seems to optimize the growth and look of the plant. Once your hala pepe is established in the garden (6 to 12 months), I recommend you stop watering it completely except during extreme drought; remember, C. forbesii naturally live in very dry places. First flowering can take a long time, up to ten years. Still, hala pepe is an incredibly beautiful plant when it flowers and well worth the care and wait.

Diseases & Pests: As noted above, chewing pests are always a concern with hala pepe, even mature large plants. Therefore, inspect the base of your hala pepe regularly; this is normally the first area attacked. Unfortunately, there is no universal defense. Chewing insects are best combated with insecticides spread around the plant or absorbed (systemic). Snails and slugs require a bait-type poison (organic or synthetic) or barriers like copper stripping. Mice and rats must either be killed with traps or poison bait, or prevented from getting at the plant by using barriers that are slippery enough to prevent climbing like corrugated drainage pipe or stacked 2L soda bottles. Leaf spot (probably Fusarium) is a common hala pepe disease on plants watered by a sprinkler or otherwise with frequently wet leaves. The easiest cure is simply to cut away or gently remove the infested leaves and adopt a watering method that keeps the leaves dry. Occasionally, hala pepe are infested by scale insects. Refer to Enemies in the Garden for methods to eliminate the scale.

Ā ā Ē ē Ī ī Ō ō Ū ū