UF/IFAS Okeechobee County Extension Service

458 Highway 98 North

Okeechobee, FL 34972-2578

Phone: (863) 763-6469

January 31, 2007

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Feature Article - for release the week of February 4, 2007

Dan Culbert - Extension Horticulture Agent

A vine on steroids

Several office visitors recently brought us a new mystery plant to identify.  Imagine a fist-sized fruit growing on a vine and a picture will emerge in your mind of this mystery plant.  Since it has been brought in by a couple of visitors, its time to break out the plant ID books and find out what we can about this aggressive vine-like weed.

With its bleeding white sap, fragrant flowers, an unusual fungal herbicide, several references to butterfly gardening, and a bit of 1940’s wartime history, today’s column will have a lot of interesting tales to tell about the Milkweed Vine. 

A Weedy Invader

This native of Argentina and Paraguay was first described in 1838.  A fast growing vine in central South America, it climbed over shrubs and trees and was found in thickets throughout those countries.

The Florida Department of Agriculture states that Milkweed Vine (Morrenia odorata) was first reported here in Florida in 1957.  It was first found in a citrus grove in Orlando, apparently from seed from an ornamental planting somewhere nearby.   Milkweed Vine continues as a difficult weed to manage in both groves, roadsides, and in urban areas on fences and ornamental plants. The first infestation furnished the seed to start many new infestations and began the spread of this pest. The Florida range is reported from Marion County south to Martin and Sarasota counties.  While confirmed reports are lacking in Okeechobee and Glades counties, our recent visitors show that Milkweed vine has now spread to the Okeechobee region.

  Flowers and "mature" foliage of the Milkweed vine.  Rapidly growing shoots have heart shaped leaves. Photo: Dan Culbert, UF/IFAS Typical of milkweeds, this plant produces a white milky sap when damaged.  Note the fuzzy stems.  Photo: Dan Culbert, UF/IFAS
Full-sized fruit from the Milkweed Vine measure about 5 inches long, and will be filled with hundreds of seed and fluffy "coma".  Photo: Dan Culbert, UF/IFAS Milkweed Vines are a problem in Citrus groves.  Note how the stems have wound around each other as they climb into this tree.  Photo: Richard Buker, UF/IFAS/CREC.

Looking at Latex Vines

Milkweed vines are perennial, so frost-free years can result in more severe weed growth.  The leaves grow in pairs on the stems, and they have a grey-green color because of a slight fuzzy texture.  Leaves on vigorous new growth have heart-shaped foliage and can be nearly 5 inches in size.  However, leaves produced on older vines have a pointy tip with a broader base, and are usually smaller in size.  

Damaging the stem, leaves or fruit will result in the plant bleeding a white milky sap, typical of the milkweeds.   This gives rise to another common name for this plant, the Latex Vine

Flowers of the Milkweed Vine are greenish-white and small.  They appear on mature vines in the midsummer. A close look at the flowers shows five small petals.  They have a fragrance that reminds some of vanilla.   

In late summer to fall the fruit grow into large seed pods.  To some it looks like a papaya or a chayote squash, others think it is more avocado-like in shape.  Mature pods measure 5 to 6 inches long and 3 to 4 inches wide. They are green until ripe, then turn somewhat yellow, tan, or brown, and will split open.

Inside the pod are hundreds of black seed.  Each seed has a bundle of white fibrous material, the milkweed floss, which is also called “coma”.  This fluff is designed to get the seed airborne when the pod splits open, taking this battalion of seed to new areas for the vine to invade.

  

A dried Milkweed pod showing the "coma" or floss which helps spread the seed by air.  Photo: Shirley Denton, Florida Plant Atlas.

 

This photo shows some individual seed of a milkweed, ready to fly. (This is not the seed from  milkweed vine, but another kind of milkweed plant!) Photo: Univ. of Arkansas.

 

De-vine control

Vines compete with the tree or shrub for light  and can shade the entire canopy if left uncontrolled.  By controlling vines, plant vigor is maintained, yields are often higher, and harvesting operations are improved.

Most vines are easier to control with herbicides when they are young seedlings. If they reach into the tree canopy they blend into the foliage and make it hard to use herbicides.  Careful application of non-selective herbicides like glyphosate can kill small vines if the spray is kept off desirable plants.  But for mature vines this will be difficult. 

There is a unique product developed to control milkweed vines in Citrus groves.  The product is a “biological” herbicide - a solution of a fungal disease (Phytophthora palmivora) is sprayed on young vines and reduces this offending weed in citrus groves.  Its name is easy to remember: De-Vine!  Because this disease can hurt certain other crops, the label limits the use of this product to groves in Polk, Hillsborough, Pasco, Lake, and Orange counties.

Caterpillars and Fluffy Stuff

As this is a milkweed plant, it will support the growth of larval Monarch caterpillars.  However, reports from butterfly gardeners suggest that Monarchs would much prefer to use native milkweeds as a food sources rather than this exotic plant.

Returning to the office visitors that brought us this weed, one recalled something about Milkweeds and the war efforts of the 1940s.   I found a few interesting references to national collection programs where people would collect milkweed for the floss.  At that time, life preservers and other cushions were filled with Kapok fiber, but because supplies of this fiber were cut off, milkweed floss was used instead. 

Since the milkweed vine did not appear here until 1957, this plant was not involved in this win the war effort.  There may be some home hobbyist that could try using the “coma” for home made cushions, but be sure that seed will not be released into the environment.

I’ve placed photos and links to more information on our Okeechobee web page, http://okeechobee.ifas.ufl.edu.  If you need additional information on Milkweed Vines, please email us at okeechobee@ifas.ufl.edu or call us at 863-763-6469.  Local residents can stop by our office at 458 Hwy 98 North in Okeechobee, and visit our Okeechobee County Master Gardeners from 1 to 3 PM on Tuesday afternoons. GO GATORS!

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Trade names, where used, are given for the purpose of providing specific information. They do not constitute an endorsement or guarantee of products named, nor does it imply criticism of products not named. 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.  Millie Ferrer, Interim Dean. Last update: 07/14/2010 .  This page is maintained by Dan Culbert 

 

references

EPA.  R.E.D. FACTS - Phytophthora palmivora MWV.  Washington: March 27, 2006. http://www.epa.gov/pesticides/biopesticides/ingredients/factsheets/redfact_111301.pdf

Futch,  Stephen H. and Hall, David W.  Identification of Vine Weeds in Florida Citrus (HS926). Gainesville: Florida Cooperative Extension Service,8/03.  http://edis.ifas.ufl.edu/HS185

Hutchinson, Jeff.  Latex plant (Morrenia odorata). Lake Placid: Archbold Biological Station, 4/03. http://www.archbold-station.org/abs/landmanage/ExoticsGrant03/ExoticsMain/latexplant.htm

Klingaman, Gerald. Milkweed pod stuffing Ornamentals Extension News - Plant of the Week – Milkweed . Little Rock: University of Arkansas, June 18, 2004 http://www.arhomeandgarden.org/plantoftheweek/articles/Milkweed.htm

Langdon,  K. R.   Milkweed Vine, Morrenia odorata --An identification Aid [Nematology (Botany) Circular No. 15].   Gainesville :  FDACS/DPI,  April 1976. http://www.doacs.state.fl.us/pi/enpp/botany/botcirc/NemBotcir15.htm

Wunderlin, Richard.  Morrenia odorata (Florida Atlas of Vascular Plants).  Tampa: Institute for Systematic Botany, USF, 2006. http://www.plantatlas.usf.edu/main.asp?plantID=24