Canavalia pubescens
Fabaceae or Pea family [Five-minute families]
Synonyms: Canavalia forbesii, Canavalia galeata var. pubescens, Canavalia haleakalaensis, Canavalia lanaiensis, Canavalia lanaiensis var. munroi, Canavalia munroi, Canavalia sericea var. lanaiensis
ʻĀwikiwiki
Puakauhi
Lavafield jackbean
Natural Range & Environment
Canavalia pubescens is a federally-listed endangered liana/vine endemic to N‘ihau, Kaua‘i, Lāna‘i, and Maui. It was last seen on Ni‘ihau in 1949 and on Kaua‘i in 2010. Currently (2021), the only known wild plants are on Lāna‘i and southeastern Maui, from 24 to 122 m (79 to 400 ft). This ʻāwikiwiki species is found in dry, open lava fields and in dryland forest, grassland, and shrubland, as well as in human-developed areas "where habitat conversion has occurred." Additionally, on Kaua‘i, it was also seen in mesic forest, grassland, and shrubland [ECOS].
When listed as endangered in 2013, it was estimated that there were less than 200 wild Canavalia pubescens. Following more extensive surveys, that number was adjusted to 99 wild plants on Maui and seven on Lāna‘i according to the last USFWS 5-Year Review [2021]. Fortunately, several State agencies and private organizations have started to mitigate the numerous threats to the species (e.g., ungulates, non-native plants, wildfires), as well as begin restoration efforts. Some of the wild and reintroduced populations are now protected by fencing and more than 6,000 seeds have been collected and stored. Additionally, a small number of plants (10 on Lāna‘i
and 27 on Maui) have been propagated and outplanted [USFWS]. Finally and thankfully, C. pubescens is commercially available (sometimes) to the public [Maui Native Nursery; Maui Nui Botanical Gardens].
ʻĀwikiwiki produces small clusters of attractive pea-like flowers (photograph courtesy of Nellie Sugii via G.D. Carr ©) that develop into large flattened pods (photograph courtesy of Forest & Kim Starr CC BY 3.0 US), each containing one to a few large seeds (header photograph courtesy of Forest & Kim Starr CC BY 3.0 US) that often rattle within their dry pod when shook. Here a cultivated ʻāwikiwiki sprawls atop a hedge of naupaka kahakai (Scaevola taccada) on the southern shoreline of Maui (Photographs courtesy of Forest & Kim Starr CC BY 2.0.). Farther inland, one wild ʻāwikiwiki creeps along the ground beneath a dry forest (photograph courtesy of Forest & Kim Starr CC BY 3.0 US) while another grows atop the ‘a‘ā lava (photograph courtesy of Forest & Kim Starr CC BY 3.0 US); note how large this vine has become.
Description
endangered Vine/Liana
Shrub, Dwarf, Less than 2
Short lived (Less than 5 years)
Stems will get woody, especially at the base, upon maturity.
Leaves wider than long and leathery. The leaves range from 1 to 3 inches and no longer than 4 inches.
Leaf Colors
Light Green
Medium Green
Flower Colors
Light Purple
Pink
Purple
Red
White
Beautiful dark red to pink or purple flowers with a white spot and streaks toward base. Botanists Otto and Isa Degener (1959) report white to pink flowers on Lānaʻi.
Blooming Period
Year Round
Sporadic
After flowering, ʻāwikiwiki form large flat pods containing tan to dark reddish brown seeds. Pods will turn dark, dry and woody and seeds will often loosen and rattle inside when ripe.
Growth Requirements
General
The seeds of Canavalia pubescens sprout easily (after scarification), and, initially, young plants grow quickly and are easy to care for. However, maintaining this ʻāwikiwiki species long term can be challenging and demanding because of repeated and severe attacks by arthropod pests, primarily lace bugs and spider mites (see below for further discussion). Therefore, if you feel you don't have the time to closely monitor for and quickly take action to control these pests, you may want to opt for a less-demanding species of native Hawaiian vine such as maile (Alyxia stellata), Bonamia menziesii, Gouania vitifolia, or pāʻūohiʻiaka (Jacquemontia sandwicensis). Additionally, in my (Koebele) experience, the O‘ahu endemic ʻāwikiwiki (Canavalia galeata) is a bit easier to maintain than C. pubescens; however, C. galeata requires a wetter habitat.
Canavalia pubescens is a climber. Therefore, consider planting it near a fence or using a trellis. In the wild, it can be seen climbing up wiliwili trees (Erythrina sandwicensis). However, C. pubescens also does just fine with nothing to climb on, in which case it tends to climb upon itself and create a spreading thicket (see photograph above). It can also be kept in a container but requires frequent pruning of its rapidly growing stems.
This dryland ʻāwikiwiki does best when grown in a site that receives full sunlight for all or most of the day. It can tolerate a bit of shading, but shaded plants may not be as silvery (i.e., fuzzy) or flower as often as plants in full sunlight. Once established (after one to two months in the ground), Canavalia pubescens requires little to no watering, and you should avoid overwatering since this can promote stem and root rot. This ʻāwikiwiki can tolerate extreme heat, drought, strong winds, and some salt spray. It will grow in cinder-rich, organic-dominant, and (coralline) sandy soils provided the soil drains water quickly.
As mentioned above, Canavalia pubescens grows quickly and, because it can fix nitrogen, normally does not require nitrogen-containing fertilizers; I never fertilized my ʻāwikiwiki except when I kept them in a pot for an extended period (i.e., over a year), in which case, I applied a balanced controlled-release granular fertilizer every six months. C. pubescens is considered to have a lifespan of ten years or less, although to date, there haven't been any scientific studies to confirm this. Unfortunately, all my C. pubescens have died after a few years because I failed to adequately monitor for and control their many pests.
Pests and Diseases
Canavalia pubescens is attacked by a multitude of pests, all sadly introduced to Hawai‘i in the last 200 years. The most frequent and serious are infestations of lace bugs (see photographs below) and spider mites, which yellow and kill the plant's leaves. Stink bugs and aphids can also sometimes become a problem. And, in moist environments, snails, slugs, and cockroaches may eat the leaves and stems of your ʻāwikiwiki.
Our Pests & Diseases page describes different ways to control/eliminate each of these pests. If the attacks on your ʻāwikiwiki are frequent and severe, you may be tempted to opt for more long-lasting controls like a systemic insecticide and miticide. However, using a systemic insecticide comes with a significant downside. Unfortunately, all the systemic insecticides easily available to the public in Hawai‘i contain imidacloprid which is extremely deadly to bees, making its use a difficult decision: "Do I kill the bees in my neighborhood in order to protect my ʻāwikiwiki?"
Lastly, it's entirely possible that your pest problem gets out of control and your ʻāwikiwiki drops all or most of its leaves. Don't panic! There's a good chance your plant can recover if you immediately start and repeatedly treat the surviving stems with an insecticide and/or miticide.
Corythucha gossypii (cotton or bean lace bug) on the underside of an ʻāwikiwiki leaf. Black spots are lace bug feces. (Photograph courtesy of Forest & Kim Starr CC BY 2.0.)
Adult Corythucha gossypii (cotton or bean lace bug). (Photograph courtesy of Forest and Kim Starr CC BY 3.0 US.)
Uses
Ancient Hawaiian
Early Hawaiians made roughly constructed fish nets and traps from stems and scoop nets probably made from ʻāwikiwiki vines for small rock paoʻo (blennies) and ʻopae (freshwater shrimps). [1,2]
Flowers used for lei making.
Another ʻāwikiwiki (Canavalia galeata) was specifically mentioned for medicinal purposes. An infusion of leaves, shoots and bark mixed with other plants as a bath for itch, ringworm and skin disorders. [3,4]
Modern
The flowers are strung on lei as they have been since the early days.
Special Features and Information
General
Fabaceae contains numerous agriculturally important plants, and is the third-largest land plant family in number of species, behind only the Orchidaceae and Asteraceae, with about 765 genera and nearly 20,000 known species [WikipediA;Fabaceae].
Canavalia are members of the very large Pea or Legume family (Fabaceae). There are six endemic species. The introduced maunaloa (Canavalia cathartica) is very closely related to ʻāwikiwiki and naturalized in some areas.
Hawaiian Name
ʻĀwikiwiki is a reduplication of ‘āwiki which means "to hurry, be quick, swift," possibly referring to the rapid growth of this vine [Pukui & Elbert 1986].
Etymology
Canavalia is derived from the Malayalam word, Kanavali, the local name for a related species in the Malabar region of Kerala, India [Wiktionany]. The species name, pubescens, is the Latin present participle of pubesco, pubescere, pubescui, and means "becoming downy-hairy" [Gledhill 2008], likely referring to the short soft hairs that cover most of the plant.
Additional References
[1] "Plants in Hawaiian Culture" by Beatrice H. Krauss, page 77.
[2] "Arts and Crafts of Hawaii" by Te Rangi Hiroa (Sir Peter H. Buck), page 312.
[3] "Hawaiian Herbs of Medicinal Value, by D.M. Kaaiakamanu & J.K. Akina, page 21.
[4] "Hawaiian Ethnobotany Online Database" http://data.bishopmuseum.org/ethnobotanydb [Accessed 2/5/13]
BPK