‘Ilie‘e (Plumbago zeylanica) — My Goto for the 3Ws.


    Whenever I'm with a group of students or volunteers, the sticky fruits of ‘ilie‘e are my goto to get them to imagine how Hawai‘i's native plants first arrived in the Islands, the most remote island chain in the world (more than 2,000 miles away from California and nearly 4,000 miles from Japan). If you don't already know, scientists believe the founder (i.e., first) plants (and animals too) to make it to Hawai‘i, arrived here via one of the 3Ws — wind, water, or wings — a powerful mnemonic. ‘IIie‘e, an indigenous species, almost certainly got to the Islands when a bird preened one of its sticky fruits from its feathers and it fell to Hawai‘i's virgin ground. The founders of other native plants such as naupaka kahakai likely arrived as fruits floating on Pacific Ocean waves, while others like Hawai‘i's native ferns arrived here as tiny spores adrift in the wind from distant lands. Biologists (according to Ziegler 2002) estimate that 95% of Hawai‘i's native ferns and 2% of its native flowering plants got to the Hawaiian Islands via the wind, none of Hawai‘i's native ferns and 23% of its native flowering plants got to the Islands by water, and 5% of Hawai‘i's native ferns and 75% of its native flowering plants got to the Islands via birds. The prevailing eastward winds and numerous stepping-stone islands to the west of Hawai‘i have resulted in a slight majority of these founder plants coming from Asia even though Hawai‘i is geographically closer to the Americas. Prior to humans, the arrival of new plants in Hawai‘i was extremely rare, with only one new species establishing itself every 105,000 years for flowering plants and every 265,000 years for ferns.   

Habitat & Appearance: An indigenous sprawling shrub with glossy slightly-crinkled leaves, and numerous white five-point flowers found in dry coastal areas, dry forest, and dry shrubland on all the main Hawaiian Islands.

    ‘Ilie‘e fruits are surrounded by a very sticky calyx (the bottom part of the flower) which helps disperse its seeds via birds and other animals. 

(Top to Bottom) Flowers & unripe fruits. Ripe fruits & seeds. Seedlings. Rooted cutting. Mature plant (photograph courtesy of Dawn Easterday ©).

‘Ilie‘e in Hawaiian Culture: Hawaiians used the sap of ‘ilie‘e to blacken tattoos. Neal (1965) has stated that the plant is poisonous, but was still used as a "baby medicine." 

Collecting Seeds: In the wild, ‘ilie‘e flower and fruit several weeks after a good rain, normally during the cooler wetter winter months. Flowering and fruiting is nearly continuous for cultivated plants. Collect the 1 cm long fruits when they are brown or black. Within each fruit, you will find one hard tan to brown elongate seed (see photos above). Discard any unripe green seeds since it's unlikely they will germinate. I have never stored ‘ilie‘e seeds because it has always been so easy to collect them from wild or cultivated plants, therefore, I cannot comment on how long seeds remain viable in storage.    

Growing from Seed: Almost no one ever propagates ‘ilie‘e from seed because it is so much easier to root cuttings. However, if you want to, this is how I do it. Sow several seeds in a berry container using Method One. The first ‘ilie‘e seedlings should appear about three weeks after sowing with others following periodically for another 2-3 months. Gently remove and repot each seedling after it develops 1-2 true leaves. In its own pot, seedlings grow rather quickly if you place them in a lightly shaded place (I keep mine under 50% shadecloth), and water them regularly. In 3-4 months, you should have a 6-12 inch tall/long plant ready for your garden or restoration site. It's during this early stage in the nursery when your ‘ilie‘e is most likely to die from overwatering, or become infested with sap-sucking pests. If it does, refer to Enemies in the Garden for treatments. 

Growing from Cuttings: Rooting ‘ilie‘e cuttings is incredibly easy. Therefore, I normally bypass Methods One and Two, and place each cutting in its own pot filled with my standard potting mix for native plants (i.e., 1:1:1; perlite: vermiculite: peat moss). I also do not use rooting hormones because it just isn't necessary. I place the cuttings directly in a shaded site in the nursery (or elsewhere) rather than inside a sealed clear container or mist chamber. I do, however, remove nearly all the leaves from each cutting, as well as the tender growing tip. Removing most of the leaves and tip sufficiently compensates for the increased evaporation from the cutting (because the surrounding humidity will be less than in a sealed container or mist chamber). Using this abbreviated method, ‘ilie‘e cuttings take 1-2 weeks to develop their first roots, and another 1-2 months to grow a new root system extensive enough to be ready for planting in the garden. As an alternative, you can also use Method Three for ‘ilie‘e cuttings, although this in-situ technique is not as successful (probably because harmful microbes in the soil kill the cutting before it can root).

Growth in the Garden: Plant your ‘ilie‘e anywhere except in a site with heavy continuous shade. For the first month or so, water it weekly until it can establish its root system. After that, your plant will only need watering if you see signs of stress like wilting or leaf loss. In a restoration setting, ‘ilie‘e can go months without rain, losing nearly all its leaves, yet bursting back to life when the rain finally returns. Both plants propagated from seed and plants rooted from cuttings grow quickly and will start flowering almost immediately if grown from a cutting or within a few months if grown from seed. Left alone, a single ‘ilie‘e can spread out to cover a large area (i.e., several square meters) in 1-2 years, and, sometimes but not always, will naturally root itself to the ground as it grows outward. As a groundcover, ‘ilie‘e does a pretty good job of suppressing weeds provided you don't let it dry out and go leafless. While I haven't needed to prune back my ‘ilie‘e very often, it can survive even extreme pruning quite well. I have never tried (or needed) to fertilize any of my ‘ilie‘e.

Diseases & Pests: I have had almost no pest or disease problems with ‘ilie‘e. Rarely, mealybugs or aphids have infested the growing tips, but in the garden or field these infestations have always disappeared after a time (probably because of natural predators). If this happens in the nursery, a few sprayings of horticultural oil or insecticidal soap should get rid of these pests. Refer to Enemies in the Garden for more details on how to eliminate mealybugs and aphids.

Ā ā  Ē ē  Ī ī  Ō ō  Ū ū