Introduction:
Coral ardisia (Ardisia crenata) Weed.
Ardisia crenata is an ornamental, cultivated for its very decorative red fruit, but it is easily naturalised and has become highly invasive in mesic forests in several regions of the world (e.g. Mascarene Islands, Hawaii, Seychelles) where it causes a reduction in the presence and diversity of native understorey plant species. Its fruit is easily spread by indigenous or introduced birds.
Description:
Ardisia crenata is a small erect evergreen shrub up to 1.5m tall, growing in multistemmed clumps with only flowering branches. Leaves alternate to 21cm long and 1-4cm wide, dark green above, waxy, glaborous with 12 to 18 pairs of lateral nerves, merging into a distinct marginal nerve which is slighty raised below. Flowering branches lateral or axillary clusters, up to 10cm long with few leaves. Flowers are small, bisexual, white to pink, often drooping below foliage. Petaloid components pinkish white, anthers yellow. Fruit is a red, glaborous 1 seeded drupe, 5-8 mm in diameter. Populations with white berries also exist.
Occurs in:
Natural forests, planted forests, riparian zones, ruderal/disturbed.
Habitat description:
Ardisia crenata thrives in the understory of mesic forests, often found in dense patches containing between 100 and 300 stems per m2.
General impacts:
Coral ardisia (Ardisia crenata) Distribution in North America shown in green.
Considered a high risk invasive in many areas, Ardisia crenata often invades the understory of mesic forests from areas where it is planted or cultivated for ornamental purposes. Ardisia crenata can significantly reduce native species diversity when present, regardless of density. It significantly increases shade in understories, often shading out native seedlings. While there is no published data supporting the theory that A. crenata is poisonous, it is suspected to be the agent of death of livestock in two seperate cases in Florida.
Notes:
A recent study comparing wild genotypes of Ardisia crenata within its native range in Japan with the genotype currently invading north central Florida concluded that traits selected for the ornamental cultivar may increase its pervasiveness in non-native habitat. Cultivar phenotypes found in Florida have dense foliage, compared to those found in Japan, which produces greater self shading and a slower growth rate. Dense foliage is more adventageous in the more open forests of Florida due to light availabiltiy. One area of the study revealed that very few seedlings were found growing within a 1 metre radius of adult plants for the Japanese genotypes, 5 or less, while up to 631 seedlings were found within a 1 metre radius of adult plants for the Florida genotypes. The thick carpet of seedlings found beneath adult plants can out compete native plants such as wildflowers.
Geographical range:
Native range: China, Democratic People’s Republic of Korea, Japan, Malaysia, Myanmar, Philippines, Republic of Korea, Taiwan, Thailand, Viet Nam.
Known introduced range:Australia, Cook Islands, Fiji, Mauritius, La Réunion, Seychelles, USA.
Close up of berries off the Coral ardisia (Ardisia crenata) Weed.
Management information:
Preventative measures: A Risk Assessment of Ardisia crenata for Hawaii and other Pacific islands was prepared. The result is a score of 7 and a recommendation of: “reject the plant for import (Australia) or species likely to be of high risk (Pacific).”
Management areas should be closely monitored for presence and frequency of Ardisia crenata. It should be subject to inter-island quarantine or banned from importation to non-native locations. A. Crenata is already barred from importation into French Polynesia. Eradication is most effective when performed within first 1 to 2 years of presence before seed production begins.
Physical: Hand pulling seedlings is effective where soil disturbance is acceptable.
Chemical: Chemical application of glyphosphate can be used on dense populations while larger, individual specimens may be cut down and stumps treated with herbicide or treated with a basal application of triclopyr. Suppresion may be accomplished through complete foliar applications of 5% v/v of Garlon 4 or Remedy. Garlon 4 or Remedy can be applied to the basal bark in an 18% v/v solution, applying no more than 8 quarts per acre and/or less than 10% of total grazed area when applying more than 2 quarts per acre. Always follow labeling instructions when applying herbicides.
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