NATIVE
RANGE
South America
DESCRIPTION
Velvet tree is an evergreen
tree that grows to about 50 feet in height when mature. Its large (up
to 3 feet long), attractive leaves are dark green above and purple underneath,
with three distinct veins that run roughly parallel from the base to the
tip of the leaf. Flowering and fruiting begin after four to five years,
when trees are about 12 feet tall, and can reoccur several times per year. Flowers
are numerous, sweet-scented, white to pink in color, and very short-lived
(12-24 hours after opening). The dark purple fruits are about one-half
inch in diameter, sweet-tasting, and very attractive to birds.
ECOLOGICAL THREAT
Velvet tree stands
create a dense canopy of shade that native plants cannot tolerate, but its
own seedlings can. Masses of it ensure very little light reaches the
ground. The shallow root system of velvet tree allows for increased
soil erosion in previously more stable areas.
DISTRIBUTION
IN THE UNITED STATES
Velvet tree is found on four of the eight main
islands of Hawaii (Oahu and Hawaii Islands, Maui, and Kauai).
HABITAT IN THE UNITED STATES
The velvet
tree occupies neotropical forests. It can be found as high as 6500
feet in elevation but also threatens lower elevations that receive high average
annual rainfall of 6 to 7 feet or more.
BACKGROUND
The velvet tree was brought
to Hawaii in 1960 as an ornamental plant. Although
initially sold at nurseries for its appealing foliage, it was officially
named a Hawaii State Noxious Weed in 1992.
BIOLOGY & SPREAD
After
four or five years of age, velvet trees can flower and produce seed, which
remains viable in soil for five or more years. Each velvet tree plant
can produce an estimated three million seeds, several times each year, creating
a massive soil seed bank. Birds are the primary vectors for dispersal
of velvet tree seeds but, because the seeds stick to shoes, clothing, tires
and other materials, humans also contribute to the spread of this noxious
tree.
MANAGEMENT OPTIONS
To prevent human
dispersal of the seeds, people working in infested areas should change clothes
and shoes before departing and thoroughly wash all machinery and other potential
dispersing agents. Uprooting young velvet trees (under about 10 feet
in height) is an effective method of control. When larger trees are
uprooted, adventitious rooting may occur but is unusual.
Velvet trees that are cut down require immediate
application of an herbicide like triclopyr (e.g., Garlon® 4) to the cut stump
surface to prevent regrowth. Professional aerial spraying of
Garlon® 4 had a 70% success rate on fruiting velvet trees, but is costly and
requires careful planning to prevent unintentional application to desirable
native vegetation.
Several methods of biological control are being
investigated and include the potential use of several insects (e.g., lepidopteran
larvae) and plant diseases (e.g., leaf spot caused by Cocostroma myconae
and a canker disease).
USE PESTICIDES WISELY: ALWAYS READ THE ENTIRE PESTICIDE LABEL CAREFULLY, FOLLOW ALL MIXING AND APPLICATION INSTRUCTIONS AND WEAR ALL RECOMMENDED PERSONAL PROTECTIVE GEAR AND CLOTHING. CONTACT YOUR STATE DEPARTMENT OF AGRICULTURE FOR ANY ADDITIONAL PESTICIDE USE REQUIREMENTS, RESTRICTIONS OR RECOMMENDATIONS. NOTICE: MENTION OF PESTICIDE PRODUCTS ON THIS WEB SITE DOES NOT CONSTITUTE ENDORSEMENT OF ANY MATERIAL.
OTHER LINKS
AUTHOR
Andrea Wise and Robert E. Lyons, Horticulture
Department, Virginia Polytechnic Institute and State University, Blacksburg,
VA
EDITOR
Jil M. Swearingen, National Park Service,
Washington, DC
PHOTOGRAPHS
Hawaiian Ecosystems at Risk Project, HI, www.hear.org
REFERENCES
Carr, Dr. Gerald. "Melastomataceae." http://www.botany.hawaii.edu/faculty/carr/melastomat.htm.
Hawaii Department of Agriculture. "The Search
for Biological Control of Miconia calvescens." http://www.botany.hawaii.edu/faculty/cw_smith/mc_control.htm.
Loope, Lloyd L. "HNIS Report for Miconia calvescens." 29
March 1997. http://www.hear.org/hnis/reports/HNIS-MicCal.pdf.
Mesureur, Germain. "Chapter 3: Plants threatened
by some alien plant species." 3.2 Miconia calvescens. http://www.uel.ac.uk/pers/1192n/dgm4.htm.
Nature Conservancy, The. "Miconia." October 1996. http://www.consci.tnc.org/library/pubs/dd/miconia.html.
Thomas, Philip. "Miconia calvescens, an
invasive melastome." 27 August 1994. http://www.metla.fi/archive/forest/1994/08/msg00065.html.
University of Hawaii Botany Department. "Distribution
Maps of Selected Alien Plants in Hawaii." 21 November 1997.
http://www.hear.org/AlienSpeciesinHawaii/AlienPlantDistributionMapsBySpecies.htm#MicCal.
Plant Conservation
Alliance, Alien Plant Working Group.
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