Native Hawaiian Garden (7722)

‘Ilima (Sida fallax) – To stand or lie down?

Hawaiians of old recognized numerous forms or types of ‘ilima. They gave many of these specific names such as ‘ilima kuahiwi (mountain ‘ilima), ‘ilima kū kahakai (‘ilima standing on the beach), and ‘ilima lei, an ‘ilima with particularly beautiful flowers that they cultivated around their homes. Today, horticulturists too are giving names to particular ‘ilima varieties such as the cultivar 'Black Coral.' A common variable is the stature of an ‘ilima shrub. ‘Ilima kū kahakai are naturally found growing near the shoreline where their prostrate form likely protects them from strong winds. Farther inland, increased height gives the taller ‘ilima kū kula a competitive advantage for sunlight over surrounding plants. (I remember hiking through a mixed shrub and grassland near Kailua-Kona, Hawai‘i where the ‘ilima were taller than me!)

Mitsuko Yorkston (2005) conducted experimental crosses between mountain (upright) and coastal (prostrate) forms of ‘ilima at the University of Hawai‘i at Mānoa. She found that much of the plant’s morphology was genetically determined and not simply a consequence of the plant’s environment. For example, when she crossed one coastal ‘ilima with another coastal ‘ilima, the offspring were always prostrate like their parents even though the new plants were grown, not along the coastline, but in pots within a UH campus nursery. Likewise, a mountain ‘ilima crossed with a mountain ‘ilima produced upright offspring when grown in the same nursery. Predictably, when she crossed a coastal ‘ilima with a mountain ‘ilima, the resulting offspring were intermediate in height. Yorkston discovered many other interesting results with her experiments. About a third of the characteristics she measured in the hybrids “showed an affinity toward one parental type” rather than being intermediate (like the plant’s height). Also, she found that ‘ilima are very bad at self-pollinating but rather need to cross with another ‘ilima to produce viable seed. You can read Yorkston’s thesis at: http://scholarspace.manoa.hawaii.edu/bitstream/handle/10125/10410/uhm_ms_3970_r.pdf?sequence=1

Habitat & Appearance: Sida fallax is indigenous to many Pacific islands; in Hawai‘i, it is found on Midway, Nihoa, and all the main islands. The varied forms are found along rocky and sandy coastlines, inland on coral plains and lava fields, and upland in dry shrublands, dry to mesic forests, and rarely in lower wet forests. Coastal types tend to be short (less than a foot) with fuzzy leaves while inland types are taller (up to 10 feet) and, generally, have glabrous or less pubescent leaves. Flowers vary from pale yellow to dark orange, often with a dark maroon throat. The five petals may be overlapping or not, regularly or irregularly shaped. Immature fruits also vary in color while ripe dry fruits are tan to brown. Each fruit contains about six small (2 mm) tan to black seeds. The seeds often have two prominent awns (horn-like structures).

Black Coral ‘ilima flower. Ripe fruit with seeds. Seedling. Wild ‘ilima kū kahakai.

‘Ilima in Hawaiian Culture: (Much of the following information comes from Kepler 1998.) Hawaiians use(d) ‘ilima primarily for lei and medicine. The woody stems were also occasionally used as slats in hale (house) frames. Flowers were harvested in the late afternoon or evening and strung together the following morning. Sometimes, to carry all the flowers back to their village, Hawaiians would weave together a temporary basket from a whole ‘ilima shrub. A single-strand ‘ilima lei requires anywhere from 500 to 1,000 flowers. Written records (Degener 1930, Handy et al. 1972) conflict on whether or not lei made of ‘ilima were reserved for royalty. ‘Ilima’s yellow-gold colored flowers were of particular significance on O‘ahu, and, today, it remains O‘ahu’s island flower. Before ma‘o hau hele, ‘ilima was Hawai‘i’s national flower. ‘Ilima is one of the plant forms Laka, goddess of hula and the forest, could assume at will. So valued for their flowers, ‘ilima lei was one of the few native plants Hawaiians purposely cultivated. Medicinally, flower buds were fed to babies and young children as a mild laxative and, mixed with other ingredients, given to adults for various ailments (Chun 1994). Pregnant women ate the flowers before childbirth, supposedly, to make the event less painful (Merlin 1999).

Collecting Seeds: Wild ‘ilima in seasonally dry areas (e.g., leeward coastlines) flower and fruit a few weeks after heavy rains. Those in continually moist locations and most cultivated ‘ilima flower and fruit continuously or repeatedly throughout the year. Harvest ‘ilima fruits (i.e., capsules) when they are dry and tan to brown. Normally, the capsules are open at this time permitting the seeds to fall out to the ground or be carried away with the wind. If you’re late, it’s not uncommon to find entire plants with seedless capsules. Don’t despair, with patience, you can often find the tiny but distinctively awned seeds in the sand or soil beneath the parent plant. Examine the seeds carefully for holes caused by insects; discard these. Further test the seeds in a cup of water. Viable seeds will sink immediately or after about an hour while inviable seeds will remain floating. Briefly sterilize the seeds (outer coat) in 10% bleach for 5 minutes (followed by rinsing with clean water) before sowing or storing. I have always sown freshly-collected ‘ilima seeds, so I cannot tell you how long they last in storage. However, in the field and gardens, I have seen ‘ilima seedlings appear a year after the last mature plant in the area had died.

Growing from Seed: Growing ‘ilima from seed has frustrated me for many years. Not because the seeds don’t sprout, but because they sprout erratically, anywhere from two weeks to six months (although most tend to sprout about two months after sowing). I have tried, without success, numerous treatments such as soaking, hot water scarification, gibberellic acid, and hydrogen peroxide to synchronize germination. Therefore, instead of using Method One or Two, I sow 20 to 50 ‘ilima seeds in a single 4-inch pot of 1:1:1 peat moss, perlite and black cinder (or a 1:2 mix or peat moss and coral sand), place the pot in the nursery where it is watered once a day, and wait. After several seedlings have developed 1 to 3 true leaves, I gently remove the seedlings (with the pot underwater to minimize root damage) and repot each in its own 2 to 4-inch pot. I, then, return the pot to the nursery and wait for more seeds to sprout.

‘Ilima seedlings grow quickly but still benefit from light fertilizing (controlled-release or foliar). Mites, aphids and mealybugs often attack the seedlings in the nursery. Keep a watchful eye for these pests, and eliminate them with sprayings of horticultural oil, a systemic insecticide, or both. In 3 to 6 months, your new ‘ilima should be several inches tall (or wide, depending upon the type) and ready for the garden.

Growing from Cuttings: I haven’t grown all the varied types of ‘ilima from cuttings (or, for that matter, from seeds). However, I’ve noticed my success has varied depending on the type and quality of the cuttings. I’ve had the most luck with ‘ilima kuahiwi and ‘ilima kū kahakai, and the least with ‘ilima kū kula. Cuttings from lush, actively growing ‘ilima have rooted more readily than those collected from plants struggling through a drought. I’ve also discovered that persistence pays off. If you have tried to grow a particular ‘ilima from cuttings and failed, don’t give up. Try again (and again), varying the time of year and the time of day (e.g., morning, evening) you collect the cuttings.

Use either Method One (preferred for fuzzy-leaf forms) or Method Two. Be certain to remove any flowers or fruits as these will divert energy away from the nodes producing new roots. They are also good hiding places for bugs that will wreak havoc later on in the container or mist chamber. It is also possible to root cuttings of some varieties of ‘ilima outside of a container or mist bench (i.e., a shady spot within your nursery). For these, plant the cuttings vertically in a 1:1 mix of vermiculite and perlite, and water daily. I have had ‘ilima cuttings develop roots in only a few weeks and those that have taken 3 to 4 months to root. Sometimes the cutting will lose all of its leaves yet still root successfully. Therefore, I only give up and discard the cutting when I can see the stem has rotted or dried out. Once the cutting has rooted, observe it closely after removing it from the container or mist chamber. If it severely wilts within a couple of hours, return it to the container or chamber and try again a week later.

Growth in the Garden: ‘Ilima can be a difficult plant to maintain in the garden. This is because many people choose to ignore its environmental requirements or assign it a purpose it is ill-adapted for. For example, most coastal ‘ilima go weeks, even months, without a drop of rain in their natural environment. Yet, many commercial and residential gardeners insist on watering their plants EVERY day. They are then surprised when their precious ‘ilima die “for no apparent reason.” Similarly, several years ago, ‘ilima kū kahakai was all the rage as the new and exciting groundcover for homes, commercial buildings, road medians, etc. No one considered at the time what they would do when these ‘ilima became infested with mealybugs, its most common pest. The mealybugs were perfectly shielded from insecticide sprays in the space between the leaves and the ground, so, in the end, most gardeners gave up and let the ‘ilima die or pulled out the hopelessly infested plants.

Plant your ‘ilima in full sun to partial shade. Heed the watering advice above; most types of ‘ilima need little (once a month) to no watering. ‘Ilima grows fast and usually flower and fruit within a year. Unfortunately, they also don’t live very long (five years, maybe, ten if you’re really lucky), so, plan on occasionally replacing them. Sometimes, this can be as easy as digging up and potting-up or transplanting an ‘ilima seedling that has sprouted beneath the dead parent or another ‘ilima in the garden. (Use Method Three for ‘ilima seedling transplants.) Prostrate ‘ilima are easiest to care for in a container or spaced out in a rock garden so you can effectively inspect the underside of the plants for pests.

Diseases & Pests: Mealybugs, with guardian ants, are the most common and damaging pest of mature ‘ilima. Refer to Enemies in the Garden for ways to combat these pests. Lush growth is sometimes attacked by aphids. Eliminate the aphids with repeated sprayings of horticultural oil, insecticidal soap, neem oil or pyrethrin. ‘Ilima leaf rust is caused by two nonnative fungi, Puccinia heterospora and Puccinia malvacearum (Gardener and Hodges 1989). The symptoms are raised brown spots with fuzzy-looking masses on the lower leaf surface and spots with sunken yellow depressions on the upper leaf surface. Leaves will often curl and fall off prematurely. Wind and splashing water can spread the rust spores from diseased to healthy plants. Treat the disease by removing all the infected leaves and discontinuing any watering from above (e.g., sprinklers). Continue to remove any diseased leaves as they appear. If the disease persists, consider using a nonsystemic fungicide. There are several available in Hawai‘i. I prefer the more natural types containing sulfur or copper. Be sure to follow the label directions exactly for the best effect and to prevent leaf burning, etc. Finally, reconsider the location and watering schedule of your ‘ilima. Often, these fungi gain a foothold because the ‘ilima were planted in the shade or overwatered. (See http://www.ctahr.hawaii.edu/oc/freepubs/pdf/PD-97.pdf for more information and photographs of ‘ilima rust.)

Ā ā Ē ē Ī ī Ō ō Ū ū