Heliotropium curassavicum
Heliotropiaceae or Heliotrope family
Synonyms: None
Heliotropium curassavicum
Heliotropiaceae or Heliotrope family
Synonyms: None
Kīpūkai
Lau poʻopoʻohina (Ni‘ihau), Nena, Poʻopoʻohina (Ni‘ihau)
Salt heliotrope, Seaside heliotrope
Natural Range & Environment
Heliotropium curassavicum is believed to be native to much of North, Central, and South America, including the West Indies. It is also thought to be an introduced and naturalized species to parts of Africa, Asian, Australia, and Europe [Al-Shehbaz 1991, page 76].
In Hawai‘i, kīpūkai is considered to be indigenous to Laysan (Kauō), French Frigate Shoals (Kānemiloha‘i), Nīhoa, Lehua Rock, and all the main Hawaiian Islands [Flora of the Hawaiian Islands], where it grows in a wide range of coastal habitats (see photo-examples below).
Kīpūkai's tiny flowers are initially all white but quickly develop a yellow throat that then turns dark purple as the flower ages (Photograph courtesy of Forest & Kim Starr CC BY 3.0; header photograph courtesy of Forest & Kim Starr CC BY 3.0 US.). Pollinated flowers develop into small swollen fruits that eventually break apart into four nutlets (Nearly-ripe fruit photograph courtesy of DouglasGoldman CC BY-SA 4.0.). Kīpūkai grows naturally in a wide range of habitats that include: periodically-flooded silty coastal flats (photograph courtesy of Forest & Kim Starr CC BY 3.0 US); sandy and rocky shorelines along with ‘ākulikuli (Sesuvium portulacastrum) (photograph of sandy habitat courtesy of Veronica McCleign CC BY-NC-SA 4.0; photograph of rocky habitat courtesy of Kenneth R. Wood (NTBG) CC BY-NC 4.0); and occasionally in dry urban areas (photograph courtesy of Alexander Wentworth CC BY 4.0).
Description
Kīpūkai is a short-lived (less than five years) prostrate and succulent herb with hairless and waxy stems and leaves that are typically bluish green in color. Its above-ground stems emerge from deep underground stems (rhizomes).
Kīpūkai has fleshy elliptic to reverse lance-like (the widest point is nearest the tip) leaves that are typically about an inch (2.5 cm) long. The leaves are arranged alternately on its stems.
Kīpūkai has numerous tiny funnel-like five-lobed perfect (bisexual) flowers that develop (typically in pairs) along a flower spike that usually has two branches coiled in opposite directions. Flowers nearest the branches' base open first with the final blooms at the tip of the spike's branches. Interestingly, the flowers are first all-white but quickly develop a yellow to greenish yellow throat. The throat then turns a dull purple as the flower ages; is this perhaps a signal to pollinators that the flower has already been pollinated? Blooming occurs sporadically to continuously year-round in both cultivated and wild plants, perhaps only taking a break during periods of extreme drought.
Pollinated flowers develop into four-lobed fruits (see photograph above). As the fruit matures, dries, and darkens, the four lobes will sometimes separate into what are called nutlets. Nutlets float in water, presumably helping with seed dispersion. Within each nutlet is one tiny seed.
In the field, kīpūkai is sometimes confused with the alien and naturalized fourspike heliotrope (Euploca procumbens; syn: Heliotropium procumbens). However, it's easy to distinguish between the two species with a closer look. Most apparent is that the fourspike heliotrope is covered with tiny hairs (on its stems, leaves, and fruits) while kīpūkai is completely hairless (see photographs below). Additional differences are:
Color — kīpūkai is typically bluish green, while the fourspike heliotrope is typically grayish green.
Succulence — kīpūkai has fleshy leaves; the fourspike heliotrope does not.
Heliotropium curassavicum (Photograph courtesy of Forest & Kim Starr CC BY 3.0.).
Euploca procumbens (Photograph courtesy of Damon Tighe CC BY-NC 4.0.).
Growth Requirements
General
Kīpūkai reminds me (Koebele) a lot of alena (Borhavia repens). Both are native Hawaiian plants that are rarely planted but almost inevitably pop up in coastal landscapes, both natural and manmade. One can only guess why kīpūkai is not a more popular cultivated native plant here in Hawai‘i, but it may be because it often loses out in planting decisions to its more long-lived sister species, hinahina kū kahakai (Heliotropium anomalum). While many consider hinahina kū kahakai more attractive and useful than kīpūkai, both can be used as groundcovers (planted a couple of feet apart), particularly in coastal areas. Kīpūkai also has the advantages over hinahina kū kahakai of growing more quickly (i.e., covering an area quicker) and of naturally reseeding and replacing itself when it dies (something hinahina kū kahakai only rarely does when cultivated).
Kīpūkai does best when planted in a site that receives full sunlight for all or most of the day and will languish if planted in heavy shade; shaded plants are less blue, more lanky, and flower less. It will grow in just about any type of soil (i.e., sandy, rocky, silty, organic, or even clay) provided the soil drains water quickly. However, it can also withstand brief periods of flooding (both fresh and saltwater), which may actually aid in its seed dispersion and germination. Natural rainfall is normally enough to keep kīpūkai alive and growing. If watered too frequently, kīpūkai tends to lose its attractive bluish tint, and can rot and die. Kīpūkai can tolerate extreme heat, drought, strong winds, and salt exposure (both in the soil and air).
Kīpūkai grows quickly, and you should have a flowering plant one or more feet (30-plus cm) across in less than a year. In-the-ground plants normally do not require fertilizer. However, if you keep your kīpūkai in a container, it may benefit from infrequent (once or twice a year) applications of a single-digit balanced organic or inorganic fertilizer. Plantings far from the ocean may also benefit from being occasionally (i.e., once every month or so) sprayed with seawater which anecdotally seems to improve growth and appearance and deter pests. However, the salt accumulating in the soil can become a problem for less salt-tolerant plants (and difficult to flush away). Therefore, unless your kīpūkai is in a container, you may want to refrain from these seawater sprayings unless you have permanently designated an area in your landscape for salt-tolerant plants.
Regular pruning of your kīpūkai's stem-tips will encourage branching and keep your plant(s) looking fuller and constantly producing new flowers. Consider using the cut stem-tips to produce new plants for your friends (see below).
Unfortunately, kīpūkai are short-lived, lasting only a couple to a few years in cultivation. However, often you will have keiki (baby) kīpūkai sprout up around your plant before it dies, thus maintaining its presence in the landscape. If you don't see any kīpūkai keikis after about a year, begin collecting the tiny nutlets or stem-tip cuttings from your plant before it dies. These can be sprouted in a pot filled with sand (fairly easy) or rooted in 100% perlite (a bit harder), respectively.
Pests and Diseases
Kīpūkai is infrequently attacked by sap-sucking pests (i.e., aphids, mealybugs, scale insects, and spider mites), particularly when grown in a suboptimal environment (e.g., too much shade or water). Snails and slugs can also acquire a taste for kīpūkai and eat its leaves and stems, sometimes consuming an entire plant in a single night! Refer to the Pests & Diseases page for ways to deal with each of these pests. Infrequent sprayings of seawater also seem to deter some of these pests.
Fungal rot, resulting in dieback or death, can be a problem if you overwater your kīpūkai. Avoid this by only watering when the surface soil is quite dry, and only planting in well-drained soil or in a container with a media mix that drains extremely well.
Uses
Ancient Hawaiian
According to Neal [1965], kīpūkai was first dried and then brewed for use as a tonic tea. Curiously, this matches one of the uses of hinahina kū kahakai (Heliotropium anomalum).
Modern
Kīpūkai foliage and flowers are occasionally used in haku and wili lei [Hawaii Horticulture].
Special Features and Information
General
Heliotropiaceae is a family of approximately 450 species of small trees, lianas, shrubs, and herbs in three genera with a worldwide distribution; however, most species are found in the tropics and subtropics. Heliotropiaceae was considered a subfamily of Boraginaceae before 2016. [WikipediA;Heliotropiaceae].
There are about 325 species of Heliotropium worldwide [WikipediA;Heliotropium], with two species native to the Hawaiian Islands, hinahina kū kahakai (H. anomalum) and kīpūkai (H. curassavicum), both coastal plants. Three non-native Heliotropiaceae are also found in Hawai‘i: the fourspike heliotrope (Euploca procumbens; syn. Heliotropium procumbens); the blue heliotrope (Heliotropium amplexicaule); and the tree heliotrope (Heliotropium arboreum; syn. Tournefortia arborea) [Flora of the Hawaiian Islands].
Hawaiian Name
Kīpū can mean "to hold back or brace, as a canoe on a wave with a paddle," while kai is often used in reference to the sea [Pukui & Elbert 1986].
Lau poʻopoʻohina and Poʻopoʻohina are names for this plant on Niʻihau, both referring to the color of the plant with hina meaning "gray or white-haired." Poʻo means "head" while poʻopoʻo means "sunken, as eyes of a sick person" or "indented, deep (as a bay penetrating the coastline." Lau means "leaf" [Pukui & Elbert 1986].
Etymology
Heliotropium is derived from the Greek words helios, for "sun," and trope, meaning "turning," in reference to the erroneous belief that Heliotropium flowers turn to face the sun [WikipediA;Heliotropium]. Leaves and flowers of other genera that turn toward the sun are referred to as heliotropic.
The species name, curassavicum, is the Latinized name derived from Curaçao, an island in the West Indies [Gledhill 2008] where this species is considered native.
BPK