Native Plants of Hawai‘i

Sida fallax

Malvaceae or Mallow family

Synonyms: Anoda ovata, Sida diellii, Sida fallax var. kauaiensis, Sida ledyardii, Sida meyeniana, Sida meyeniana var. microphylla, Sida nelsonii, Sida sandwicensis, Sida sertum

ʻIlima

Natural Range & Environment

Sida fallax is native to many Pacific islands from Hawai‘i westward to China. In Hawai‘i, it is found on all the main Hawaiian Islands as well as Midway Atoll (Pihemanu) and Nīhoa from sea level to 1,980 m (6,496 ft) [Wagner et al. 1990]. Core samples taken from the lake at the center of Laysan (Kauō) contained pollen from a Sida species [Athens et al. 2007]. This suggests Sida fallax may have grown on additional Hawaiian Islands in the pre-historical past. Recently, Sida fallax was planted on Laysan [Starr & Starr 2013].

‘Ilima has a wide geographic and ecological range in Hawai‘i, being found naturally along rocky to sandy coastlines, slightly inland on coral plains and lava fields, and upland in dry shrublands and dry to mesic forests. Wagner et al. [1990] states that Sida fallax is also found rarely in low wet forests; however, neither of us have observed this.

ʻIlima flowers can have varying amounts of red. Ripe ʻiIima capsules are dry and tan, and typically split open to release their tiny seeds. ʻIlima leaves can also vary in shape, color, and pubescence (hairiness). An assortment of cultivated forms. (Potted ‘ilima photograph found on Acufree.com. Photograph of cultivated prostrate ‘ilima courtesy of Cliff CC BY 2.0. Photograph of cultivated upright ‘ilima courtesy of Greg Koob ©.)

Description

Of the many native Malvaceae in Hawai‘i, Sida fallax has the widest geographic range and displays the most morphological variation. Coastal types tend to be short (less than two feet [60 cm] tall) while inland types are taller (up to six feet [2 m] tall). A study by Mitsuko Yorkston [2005] found that much of an ‘ilima’s morphology was genetically determined and not simply a consequence of its environment.

The stems of Sida fallax are most often light gray, but some forms have darker bark. Depending on origin and moisture levels, ‘ilima leaves can be quite small (less than one inch [2.5 cm]) to large (over three inches [7.6 cm]). Leaves can also vary in shape (oval to arrow-like), degree of margin serration, and pubescence (hairy to hairless), with coastal forms generally being fuzzy and inland forms being less hairy or glabrous (hairless). The degree of pubescence and underlying leaf color can also combine to yield leaves that appear light to dark green to gray or bluish silver.

Sida fallax flowers are perfect (bisexual). Their flower petals vary from pale yellow to bright or dark orange with or without a red to dark maroon throat. The five petals may be overlapping or not, regularly or irregularly shaped. Some ‘ilima forms have a dark maroon calyx (flower base). 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. Each flower lasts only one day.

Immature ʻilima fruits can vary in color, while ripe dry fruits are initially tan, turning darker with age. Each fruit contains about six tiny (2 mm) tan to black seeds. The seeds often have two prominent awns (horn-like structures).

In our experience, ‘ilima don't live long in cultivation — five years, maybe, ten if you’re lucky — so plan on occasionally replacing them. We cannot comment on their lifespan in the wild.

Interestingly, a recent genetic study by Mersedeh Pejhanmehr [2022] revealed that despite Sida fallax's significant morphological variation, the genetic phylogenies generated by her study showed that it is a single species throughout the Pacific region and the different forms of Hawaiian S. fallax are not genetically distinct at the sequence level. Pejhanmehr also found that populations on a single island were more closely related to each other than they were to populations on other islands.

Growth Requirements

General

The morphological diversity of ʻilima provides an equally diverse number of uses in the landscape. Low-growing forms are great as a groundcover or to control erosion. More upright forms can be used as a single garden accent, informal hedge, or screen. All forms can be grown to maturity in a container.

‘Ilima can be a difficult plant to maintain long-term in a landscape. 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 dies “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 up the hopelessly infested plants.

Plant your ‘ilima in a site that receives full sunlight for all or most of the day. Montane forms do well in full sun, but are also more adaptable than coastal forms to a site that is shaded for a good portion of the day. Heed the watering advice above; most ‘ilima are coastal forms that need little (once a month) to no watering once they are established in the ground (after about a month); montane forms generally require more frequent watering (e.g., once a week). Stop watering (particularly with sprinklers) and treat your plant if fungal diseases begin to appear.

Sida fallax grows fast and usually begins flowering 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, potting (to give it time to recover and grow larger), and then transplanting an ‘ilima seedling that has sprouted either beneath the dead parent or another ‘ilima in your landscape. If your ‘ilima starts putting out yellow leaves or seems to be growing too slowly, you can try applying a balanced controlled-release fertilizer with minor elements every six months or spraying the leaves monthly with an organic or inorganic water-soluble fertilizer diluted to ⅓ to ½ the recommended strength. However, don't overdo it or your ‘ilima will develop extra-large and papery leaves, stop flowering, and become a "bug magnet."

Prostrate ‘ilima are easiest to care for when kept in a container or spaced out in a rock garden so you can effectively inspect the underside of the plant(s) for pests and treat it if needed. They look beautiful on a mound of black cinder along with their common seaside companion pāʻū-o-Hiʻiaka (Jacquemontia sandwicensis).

‘Ilima don't seem to be very picky about soil type and will grow in sandy, coralline, cinder/lava, clay, or organic-dominant soils. However, whether it is in the ground or a container, your ‘ilima requires easily draining soil or media, respectively. Coastal forms are tolerant of extreme heat, drought, strong winds, and salt spray. Montane forms are less tolerant of all these elements.

With so many different forms of ‘ilima, you should expect some types to be more difficult to keep than others. Here are four generalizations we have made from our observations over the years, all subject to exceptions:

Mealybugs seem to prefer fuzzy (hairy) ‘ilima over more glabrous (hairless) forms, and prostrate ‘ilima over more upright types.
Snails, slugs, and spider mites all seem to prefer glabrous ‘ilima over fuzzier forms.
All forms of ‘ilima appear equally susceptible to fungal infections, particularly when overwatered.
Since most cultivated ‘ilima are xeric coastal forms, overwatering is the most frequent cause of death.

Therefore, if you find yourself with an ‘ilima that just takes too much work to maintain, consider trying another form. Depending on the environmental conditions (i.e., light, water, wind, soil), we've found some types will require a lot of care to keep them pest and disease-free, while other forms are more "bulletproof."

Pests and Diseases

When it comes to pests on ‘ilima, it's 90% about the ants! Mealybugs (and to a lesser degree, aphids and scale insects), farmed and protected by ants, are the most common and damaging pest of cultivated ‘ilima. You can kill the mealybugs with insecticides, but they will only be replaced in a few days or weeks by new ones imported by ants if you don't also eliminate, or at least manage, the ants. Refer to the Pests & Diseases page for ways to control ants.

‘Ilima kept indoors or in windless sites are prone to spider mite infestations, while those kept in shady wet areas may be attacked by snails and slugs or acquire a black mold on their leaves and stems. In both situations, first, try moving your ‘ilima to solve the problem. If moving is impossible or doesn't help, refer to the Pests & Diseases page for other solutions.

‘Ilima are sometimes afflicted by ‘ilima leaf rust (see photograph below), a disease caused by two nonnative fungi, Puccinia heterospora and P. malvacearum [Gardener & 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. We 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 was 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.)

‘Ilima leaf rust (Photgraph courtesy of Scot Nelson public domain).

Uses

Ancient Hawaiian

Hawaiians occasionally used the woody stems for ‘ilima as slats in hale (house) frames, for temporary baskets, and as a covering on pebbled floors in hale under the floor mats and sleeping mats [Handy & Handy 1972; Neal 1965]. ʻIlima kū kala, along with other plant materials, was placed over hot stones in an imu. The food was then placed atop these to prevent it from being scorched by the stones [Krauss 1993].

However, ‘ilima was primarily used by Hawaiians for lei and medicine. 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 [Kepler 1998]; Krauss [1993] states the flowers were harvested early in the morning before they opened. A single-strand ‘ilima lei worn around one's neck required about 1,000 flowers [Krauss 1993]. Written records [Degener 1973, Handy & Handy 1972] conflict over whether or not lei made of ‘ilima were reserved for royalty because they resembled the yellow-feathered lei worn only by aliʻi. So valued for their flowers, it is believed that (some forms of) ‘ilima were one of the few native plants Hawaiians purposely cultivated [Kepler 1998]. Another name for a lei made from ‘ilima flowers was lei ʻāpiki because it was believed to attract mischievous spirits. Because of this, some Hawaiians would not wear this type of lei, while others considered it lucky [Pukui & Elbert 1986].

According to Krauss [2001], the juice from mashed ‘ilima flower buds was fed to babies as a mild laxative and, mixed with other ingredients, given to children for thrush (ʻea), or, in another mixture, given to patients with asthma. Lastly, pregnant women during labor ate the flowers, supposedly to make the event less painful. Refer to the Hawaiian Ethnobotany Online Database for other possible medicinal uses.

Modern

‘Ilima lei are still very popular today. However, because of their perishability and the number of flowers required, real flowers are sometimes substituted with artificial paper or plastic ones. The edible flowers are sometimes used to garnish foods such as gelatin molds. The flowers are mildly sweet to tasteless but have a refreshing clean aftertaste.

Special Features and Information

General

The large Mallow family, Malvaceae, contains about 4,200 species within 244 genera, with notables such as okra, cacao, durian, baobab, kenaf, and cotton [WikipediA;Malvaceae].

Sida fallax is the only species in the genus Sida native to the Hawaiian Islands, although there is some debate as to whether Sida rhombifolia is native or naturalized. Currently (2025), there are six other naturalized Sida species in Hawai‘i [Flora of the Hawaiian Islands].

ʻIlima is one of the dominant shrubs on Nīhoa, and its flower buds provide food for the critically endangered Nīhoa finch (Telespiza ultima), an endemic bird restricted to the island [Pratt 2005].

Queen Emma Kalanikaumakaʻamano Kaleleonālani Naʻea Rooke (1836–1885) favored lei ʻilima over all other lei [McDonald & Weissich 2003]. Pua ʻilima (Sida fallax) was designated as the official flower of Oʻahu in 1988 [state symbols USA].

Hawaiian Name

Hawaiians of old recognized numerous forms of ‘ilima, and because the plant was important to them, gave many of these forms specific names based on their geography. Pukui & Elbert [1986] describe many of these, such as:

ʻilima kuahiwi — a wild ʻilima "of the mountains."
ʻilima kū kahakai — a wild type of creeping ʻilima "standing on the beach," probably the same as ‘ilima papa.
ʻilima kū kula — a wild type of ʻilima "standing on the plains" not often used for lei.
ʻilima makanaʻā — a wild type of ‘ilima with small flowers and medium height growing on old lava beds in Kaʻū.

Similar to what we do today with roses, Hawaiians used adjectives (modifiers) to name ‘ilima with specific flower colors or uses such as:

ʻilima koli kukui — a rare domesticated ʻilima from O‘ahu with bronze-red flowers.
ʻilima lei — a domesticated form used for lei, probably the same as ‘ilima mamo.
ʻilima ōkea — a domesticated form light yellow in color. [Pukui & Elbert 1986].

Undoubtedly, there were additional ancient names for ‘ilima now forgotten, as well as those used only by some Hawaiians, such as ʻilima laukahi (‘ilima with a single leaf) and ʻilima lau liʻi liʻi (‘ilima with small leaves), names limited to Niʻihau [Wichman & St John 1994].

Etymology

The genus name, Sida, comes from a name used by the Greek philosopher and naturalist Theophrastus (c.371 – c.287 BCE) for both a water lily and a pomegranate tree [Gledhill 2008]. The species name, fallax, means "deceitful, deceptive, false, or bent" [Gledhill 2008].

BPK