UF/IFAS
Okeechobee
County
Extension
Service
458
Highway 98 North
Okeechobee
,
FL
34972-2578
Phone:
(863) 763-6469
E-
mail: dfculbert@ifas.ufl.edu
June
2, 2004
Feature
Article - for release the week of
June
6, 2004
Dan
Culbert - Extension Horticulture Agent
Rubbervine
- a new invader?
An
office visitor brought in a plant to identify last week.
It looked to me a bit like an 
Allamanda
vine, and had white sap, but the
color of the flower was lavender, not pink.
And it had a seed pod, filled with what our visitor described as
dandelion-like. He liked the
appearance of the plant, wanted to know how to make it grow, but had some
concern that this volunteer might be a new invader.
Apparently
he was right and I was wrong. I
sent photos to the University
of
Florida
herbarium and Weed Scientist Dr. Ken Langeland, who put me back on the right
track. Our visitor, Jim Shaffer,
may have uncovered our county’s first volunteer appearance of Rubbervine.
In some areas, this attractive milkweed relative has escape cultivation
as an ornamental and had been used as source of rubber.
In
the landscape, this plant is a twining vine or shrub, and can grow very fast
to12 feet tall. It’s thick shiny dark green leaves
are about 2 inches long, and the slightly pointed leaves grow across from each
other on the stem. Stems can be
green or purple in color. The plant
has also been called Purple Allamanda because its flowers do look like the more
well know Pink Allamanda. Rubbervine
has large, showy flowers with a broad funnel-shaped tube and five petal-like
spreading lobes. The 2½ inch
tubular flower can be either lilac purple or red purple.
What also clued me in that my initial identification was wrong as the presence
of a triangular seed pod, filled with hundreds of winged seed.
It is highly unusual to see seedpods produced on Allamanda.
For Allamanda to escape, stems would have to be carried by natural forces
(or man) to establish in a new location.
Rubbervine
seed pods are rigid and grow in pairs at the end of a short stalk. The pods are
4-5 inches long, 1-2 inches wide and each can contain up to 450 brown seeds.
Each seed has a tuft of long white silky hairs which enable easy dispersal by
wind and water. This makes it easy
for the plant to spread from one location to another.
There are actually two different species of Rubbervine - Palay
Rubbervine (Cryptostegia
grandiflora)
[on left] and Madagascar Rubbervine, 
C. madagascariensis.
[on right] .The botanical name of this second species may give a clue that this plant
comes from
Madagascar
in
Africa
.
These two species differ in color of the flower and stem. They are widely
cultivated as ornamentals in many warmer areas, but have escaped cultivation in
Australia
and
Hawaii.
In
Florida,
specimens of Rubbervine have been found in Collier, Monroe, Broward, Lee,
Manatee and Hendry counties. And
with Jim Shaffer’s find, we will add Okeechobee to the list.
This plant has several attributes as a landscape plant: it is easy to grow,
adaptable to many planting sites, drought and pest tolerant, and requires little
supplemental fertilizers. Its
colorful flowers and brilliant dark leaves make it a good choice to cover a
trellis or a fence. It can be found in area nurseries and is reasonably priced.
These characteristics also make it able to make the great leap from cultivation
to natural areas. This is why
Rubbervine has been added as a Class II (potentially invasive) member of the
invasive plant list maintained by the Florida Exotic Plant Pest Council.
This list does not prohibit the use of this plant, but implies this
warning: if you plant it, be responsible and insure that it does not spread
beyond its intended place in the landscape.
Rubbervine was formerly grown in Madagascar
and India
to produce poor quality rubber latex. The
white milky sap is poisonous it contains substances that can cause heart
problems and getting it in the stomach can be upsetting.
When trimming this plant, wear gloves - the sap is irritating to the
skin. Discard trimmings rapidly, because the dust from dried plants is also
irritating.
If you need additional information on rubbervine,
call or stop by our office at 458 Hwy 98 North in Okeechobee. Visit our Master
Gardeners on Tuesday afternoons from
1
to
5
PM
on Tuesday afternoons, or call our phone number at 863-763-6469 or email us at okeechobee@ifas.ufl.edu.
-30-
References
Faucon, P.
India Rubber Vine, Purple Allamanda Phoenix: Deser-Tropicals website,
2003. http://www.desert-tropicals.com/Plants/Asclepiadaceae/Cryptostegia_grandiflora.html
Forest Starr, F.,
Starr, K. and Loope, Lloyd. Overview: Cryptostegia
spp. Rubber vine. Maui, Hawai'i: USGS Biological Resources
Division - Haleakala Field Station, January 2003. http://www.hear.org/starr/hiplants/reports/html/cryptostegia_spp.htm
Gilman, E. Mandevilla
splendens (Pink Allamanda). Gainesville: UF/IFAS Extension Service,
Fact Sheet FPS-399,
October 1999.
ibid.
Allamanda violacea (Purple Allamanda) Gainesville:
UF/IFAS Extension Service, Fact
Sheet FPS-32, October 1999.
The
Florida Cooperative Extension Service - Institute
of Food and Agricultural Sciences is an equal opportunity/affirmative action
employer authorized to provide research, educational information, and other
services to individuals and institutions that function without regard to race,
color, sex, age, handicap, or national origin.
Florida
Cooperative Extension Service / IFAS /
University
of
Florida
.
Larry
A. Arrington, Interim Dean.
Last update: 06/10/2004
. This page is maintained by Dan
Culbert 