Cat's claw (Caesalpinia decapetala) An Alien Plant Report Prepared by: Forest Starr, Kim Martz and Lloyd Loope United States Geological Survey Biological Resources Division In cooperation with: American Water Works Association Research Foundation Maui County Board of Water Supply March, 1999 Cat’s claw (Caesalpinia decapetala) What is cat’s claw? Cat’s claw is a thorny vigorously growing woody vine with yellow flowers and brown seed pods which forms a dense canopy, and smothers vegetation, fences, forests, and pastures. Cat’s claw is found on all the main islands except Lana'i. On Kaua’i, a dead cow was found tangled and upside down in a thorny thicket. On Maui, cat’s claw is currently restricted to Kakipi (Halehaku) gulch on the windward north shore. What should you do if you see this plant in areas other than Kakipi gulch? 1. Call the Hawai'i Ecosystems at Risk (HEAR) project at 572-4418. 2. Dig out the root of the vine, if possible. Otherwise, cut the vine near the root of the plant, and treat with an herbicide in accordance with label. 3. For more information or additional copies of this flyer, call 572-4418 or websurf to www.hear.org. You can help keep Maui no ka oi. United States Geological Survey Maui County American Water Works Association Biological Resources Division Board of Water Supply Research Foundation Cat's claw (Caesalpinia decapetala) 2 Cat's claw (Caesalpinia decapetala) Overview: Cat's claw or Mysore thorn is a woody vine with sharp thorns and yellow flowers that forms impenetrable thickets (Wagner et al. 1990:647). This native of tropical Asia can be found on all the main islands except Lana'i and Kaho'olawe. (Rezents 1998). This species was introduced as a fence plant for ranches before 1910 (Wagner et al 1990), but the recurved thorns proved lethal, killing a cow on Kaua'i (R. Hobdy pers. comm.). Cat's claw is widespread on Kaua'i and O'ahu, and beyond control. On Maui, cat's claw is restricted to one gulch, Kakipi (Halehaku). This population of cat's claw is thought to have come in on equipment from another island during construction of the new bridge. With sharp thorns all the way to the ground, controlling cat's claw in this steep gulch would be difficult. Cat's claw may not be a feasible target for eradication, but through delineation of the area and education, it may be possible to keep it from invading throughout the watershed. Public Involvement: Using volunteers for physical control may not be very feasible, but the proximity to the highway does allow educational opportunities. This site allows easy access to feel the sharp prickles and see the last bits of native forest and adjacent pasture land being taken over by cat's claw. Parking at either the bridge or satellite population and seeing the plant first hand is impressive and well worth the stop. Groups that could become involved with cat's claw include the cattleman's association, road crews, water professionals, na opio o ka aina, and the Sierra club. There are of course many more groups that can help contain cat's claw to Kakipi gulch and prevent its spread to other parts of the island. People who learn about the plant and the know the plant can keep their eyes open for more elsewhere. If a small outlier population was found, volunteer groups could be mobilized to control the new population. Telling others about cat's claw, passing out flyers, copies of this report, and other information about cat's claw will help prevent its spread and further establishment on Maui and in the watershed. Common Name: Cat’s claw, wait-a-bit, mysore thorn, thorny poinciana, puakelekino Latin Name: Caesalpinia decapetala (Roth) Alston (Wagner et al. 1990) Synonyms: Reichardia decapetala Roth; Biancaea sepiaria (Roxb.) Tod.; Caesalpinia sepiaria Roxb. (Wagner et al. 1990; Haselwood et al. 1983). Taxonomy: In the Fabaceae (Pea) family, Caesalpinia is a diverse genus of 70 or more species of trees, scandent to climbing shrubs (often thorny), and perennials found in scrub and lowland rainforest, and on mountain slopes in tropical and subtropical areas (Brickell et al. 1997). Most Caesalpinia are evergreen, some loose leaves in the tropical dry season. The leaves of all Caesalpinia are bipinnate, some very large with numerous leaflets , the flowers are in spikes from the upper leaf axils and may be quite showy, mostly in shades of red, yellow or cream, with separate petals and often conspicuous Cat's claw (Caesalpinia decapetala) 3 stamens. The seeds are in typical leguminous pods (Turner et al. 1997). The widespread species C. bonduc, C. crista, and C. major have been greatly confused since Linnaeus applied C. bonduc to two different species. A survey of the nomenclatorial history is given by Hattink (1974); his conclusions have been followed here. Thus for Hawai'i the species generally known as C. crista is referred to C. bonduc, and C. jabayo becomes C. major. Named in honor of Cesalpino (1519-1603), Italian botanist, philosopher, and physician to Pope Clement VIII (Wagner et al. 1990) Other Caesalpinia species known to be occurring in the state of Hawai'i include C. bonduc, (indigenous), C. kavaiensis, (endemic and endangered), C. major (introduced). Description: Climbers or shrubs with sprawling branches, forming large impenetrable thickets, with recurved prickles on young branches and leaf rachises. Leaves with 3-15 pairs of pinnae, leaflets 5-12 pairs per pinna, oblong-elliptic, 1-2.2 cm long, 0.4-1.1 cm wide, apex rounded, stipules deciduous, obliquely ovate, 8-20 mm long, entire. Flowers perfect, 25-30 mm in diameter, in axillary and / or terminal racemes, when axillary often serial; petals yellow, upper one veined or blotched with red, 12-15 mm long. Pods dehiscent, slightly swollen, 6.5-11 cm long, 2-3 cm wide. Seeds 4-9 black, ellipsoid, laterally flattened, 8-12 mm long, 6-8 mm wide (Wagner et al. 1990). Noxious weed acts: Currently not on State of Hawai'i Noxious Weed list, but listed by three sources in the weed list database created for this project including Greening Australia project, University of Hawai'i Botany Department, and Department of Land and Natural Resources. Declared noxious for state land leases (Haselwood et al. 1993). In Australia, it is listed as an environmental weed of subtropical rainforest and remnants in New South Wales (Nagle 1995). Declared a noxious weed in South Africa (PIER website). Native range: Native to tropical Asia, India, and China (Haselwood et al. 1993; Turner et al. 1997). Range of invasion: Global - Successfully invaded Hawai’i, Australia, subtropical New Zealand islands, Fiji, French Polynesia, and New Caledonia (Wagner et al. 1990; PIER web site). State -- First recorded in Hawai'i in 1888 (Stone et al. 1992), it can be found naturalized along roadsides, near abandoned house sites, and other disturbed areas, 0 – 250 m, on Ni’ihau, Kaua’i, O'ahu, Lana'i, Moloka’i, East Maui, and Hawai’i (Wagner et al. 1990). Infestations can be found along the Honouliuli trail of the Wai’anae Mountains and on the windward side of O'ahu, the upper pastures and adjacent forest of much of northeastern Kaua’i, and Kakipi (Halehaku) gulch, Maui (Wagner et al. 1990). Maui -- Cat's claw can be found Paia side of twin falls at Kakipi (Halehaku) gulch. The yellow flowered vine can be seen growing on the walls and flat surfaces of the valley. It even covers mango trees in the distance (Rezents 1998). The greatest density is found near the bridge on Hana highway. The density drops off on either side, but cat's claw can Cat's claw (Caesalpinia decapetala) 4 be found all the way to the ocean and almost a mile mauka of the Hana highway. A satellite patch was found in a nearby tributary, just East of Kakipi gulch. Climate where invading: Found in gulches, along stream beds, and in moist regions. A weed in pastures, range lands, and waste places (Haselwood et al. 1993). Value to humans: Can be used as a fence plant for ranches, as it forms impenetrable hedges. Introduced as an ornamental (Stone et al. 1992). Problems: Cat's claw is extremely thorny and aggressive. It climbs on vegetation, has a smothering habit and makes walking impossible. State Forester Robert Hobdy (pers. comm.) saw a dead cow in a thicket on Kaua’i. Apparently the animal had gotten caught and struggled to free itself. The cow ended up suspended on the thicket four feet above ground with its four legs sticking straight up (R. Hobdy pers. comm.). Cat's claw presents a formidable opposition for ranches and has the capability to take over large areas of land. Besides taking over pasture, cat's claw can engulf native forest, water delivery systems, and other utility right of ways. Biology and ecology: The medium sized seeds may be dispersed by rodents and granivorous birds, but man is almost certainly the principal dispersal agent in Hawai’i (UH Botany web page). Water may also wash seeds downstream. Large numbers of yellow flowers tend to appear during winter and spring on Maui. Insect found on cat's claw on Maui include the Sonoran carpenter bee (Xylocopa sonorina), bean butterfly (Lampides boeticus), honey bee (Apis mellifera) and ants (Technomyrmex albipes). The first three were found on the flowers and could potentially be pollinating the flowers. The ants were found in the seed pods. Fungal canker, dieback, spider mite, whitefly, and mealy bug problems can occur on cat's claw (Brickell 1997).