Okeechobee County sealUF/IFAS Okeechobee County Extension Service

458 Highway 98 North

Okeechobee, FL 34972-2578

Phone: (863) 763-6469

E- mail: okeechobee@ufl.edu

December 15, 2011

Feature Article - for immediate release

Dan Culbert - Extension Horticulture Agent

There’s Snow in Florida!  

Many roadsides in Okeechobee have lots of white colored flowers that may give the ground a “snowy look”  Photo: Dan Culbert, UF/IFAS A closeup of the “snow” shows lots of light- colored flowers being enjoyed by honeybees.  Photo: Dan Culbert, UF/IFA

 

Many long-time residents of our area have never seen snow.  It’s that white, cold stuff that blankets the ground, making for those old-time holiday postcards typical of northern winter festivities. 

 

Recently, I have received several calls about what some people think looks like a dusting of snow over our local Florida Yards. But on closer inspection, they see it is a creeping, low growing weed that blooms with lots of small light colored flowers. Today’s column is about this spreading weed that some are now calling “Florida Snow.”

There are several common names for this plant, which, as normal, cause confusion.  I’ve only recently heard this called Florida snow, but feel that it is an inappropriate name.  There are some references that disagree, but the ones I trust the most call it Largeflower Pusley, which is almost as difficult to remember as its botanical name, Richardia grandiflora. Since the experts believe it to be a native of South America, another name – Rough Mexican Clover – is also deceiving: it is not from Mexico, nor is it a clover relative.

This plant is closely related to a number of pan-tropical plants such as Gardenia, Ixora, Penta Firebush and Wild Coffee. This family includes three very common, look-alike weeds with differences in the size of the flowers and the coarseness of the foliage.  All of these plants are named Richardia for English botanist Richard Richardson (1663-1741).  Take a look at the photos and you can see the differences:  

Largeflower Pusley or Largeflower Mexican Clover, Richardia grandiflora. Photo: Patricia Howell, Florida Atlas of Vascular Plants  

Florida Pusley or Rough Mexican Clover, Richardia scabra.  Photo: Brandon Fast, UF/IFAS.  Also see: Florida Atlas of Vascular Plants   Tropical Mexican Clover or Brazil Pusley, Richardia brasiliensis. Photo: Paul Redfearn, Florida Atlas of Vascular Plants

·         Largeflower Pusley/  Largeflower Mexican Clover (R. grandiflora) has the largest, showiest flowers of these three plants.  The leaves are narrow, tapering sharply to points at both ends, and have a distinct leaf stalk (petiole) The flowers are almost an inch (2cm) long, clustered at tips of stems, and can be white, pink, blue or violet. On cloudy days, the flowers remain unopened.

·         Florida Pusley is the only native of the group.  It is a common annual weed in lawns, gardens and pastures.  R. scabra is Latin for "rough,” referring to the stems of the plant. The number of flowers in the cluster is fewer and smaller that these other weeds.  It has all white flowers and hairy seed capsules

·         Tropical Mexican Clover (R. brasiliensis) is similar but has much smaller all white flowers and hairy seed capsules – the fruits. The edge of the leaf is smooth, and the thickened roots break easily when pulled. This is a perennial plant with a large distribution range. It is not as commonly a problem weed.

Now that you can distinguish Largeflower Pusley from these other weeds, note that its creeping low growth habit allows it to escape the blades of the mower.  Largeflower pusley tolerates temperatures as low as 10°F, and if it does not freeze, it will live on from year to year, slowly spreading and rooting at the nodes.   The many flowers also mean it reproduces by seeds as well. Flowering is heaviest from September into January.  Small pieces of fleshy taproots left in the ground will resprout, helping single plants form three-foot wide mats.

Collier County Agent Doug Caldwell reports that in time of drought, Largeflower Pusley will not be wilted when all other grass around it is dry and crisp.   Is this newest rage in drought-tolerant groundcover? The flowers can also attract butterflies and bees: one enthusiastic butterfly gardener calls this plant Fairy Cups as a result of its attraction as a nectaring plant.  And there are even some reports that it is and edible weeds, but I’ve not found reliable conformation of that idea.

A lawn or pasture can have thousand of flowers capable of dispersing tens of thousands of seeds.  Controlling the spread when so many seed are produced can be difficult. Homeowners may be tempted to hand weed small patches, but since the seed are quite small, even with care many will fall to the ground and come back again in open patches in the turfgrass.

 

Stopping the Spreading Snowbank

Seed from Florida Pusley are similar in size to that of other Richardia weeds.  about 1 millimeter wide by 2 mm. long.   Photo: Steve Hurst ©USDA-NRCS PLANTS Database

In a 2007 report, a University of Florida researcher found that none of the herbicides tested had a strong or lasting effect on Largeflower Pusley. Lee County Extension Director Stephen Brown reports that repeated applications of Atrazine are said to provide good control. The effect of Atrazine will not be seen for at least a couple of weeks. In cooler months, homeowners are largely confined to the use of Atrazine or Image plus Atrazine on their St. Augustine lawns.

 

Atrazine can be found in liquid or granular forms. The liquid formulation gives much better control of largeflower pusley and other weeds than the granular form. Liquids should have a 4.0% concentration. The granular forms are usually blended with fertilizer and sold as Weed & Feed.  Granular Atrazine concentrations are usually less than 1%, that are not sufficiently concentrated to manage largeflower pusley. Several applications, several weeks apart would be necessary for noticeable control. Do not use Atrazine when temperature rises above 88°F.

 

Another herbicide, Mansion [Metsulfuron methyl] is recommended for, among other things, large-flower pusley control only in St. Augustinegrass lawns. (It is currently available at John Deere Landscape stores.)  The main problem with using Mansion is the small amount required per application. Mansion should be applied by commercial landscapers that have the equipment and expertise to do this. Read and follow label directions for all herbicides used.

In pastures and in vegetable fields, there is research on which commonly used pasture herbicides worked well on Florida pusley.  Such information may be of use in forming weed management plans directed towards largeflower pusley. Preventing seed production is the key management strategy. This weed emerges year round, and this steady emergence can be used to lower the populations in the fallow season between crops. Use labeled site-specific preemergent products during the growing season, as any escapes can be difficult to control. If a postemergent application is necessary, make the application when the weed is actively growing to maximize control.   

I’ve placed more information on our Okeechobee web page, http://okeechobee.ifas.ufl.edu.  If you need additional information on these spreading weeds, please email me at okeechobee@ufl.edu   or call 863-763-6469.  Local residents can stop by our office at 458 Hwy 98 North in Okeechobee.  Go Gators and Happy Holly Days!

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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 Chancy, Interim, Dean. Last update: 12/15/2011.  This page is maintained by Dan Culbert  

References  

Andrew W. MacRae, A. W.  Florida Pusley Biology and Control in Fruiting Vegetables. [HS1172]. Gainesville: UF/IFAS Cooperative Extension Service, May, 2010.  http://edis.ifas.ufl.edu/hs1172  

Brown, S. “It'll be hard to get rid of lawn flowers.”Ft. Myers: NewsPress.com, December 4, 2010. http://www.news-press.com  

Brown, S. What’s Blooming? November December Ft. Myers: UF/IFAS Lee County Extension Service, 12/2010. http://lee.ifas.ufl.edu/Hort/Videos_and_Powerpoints/Richardia_grandiflora.pdf

Caldwell, D. “Walkable Groundcovers.”  Ft. Myers: Lee County Extension Service, February, 2011. http://lee.ifas.ufl.edu/Hort/GardenPubsAZ/Walkable_roundcover_Alternatives%202011_Caldwell.pdf

Caldwell, D. Drought Conditioning Your Lawn.  Naples: UF/IFAS Collier County Extension Service, undated. http://collier.ifas.ufl.edu/CommHort/CommHortPubs/TurfDrought.pdf

Fast, B., Ferrell, J. and Sellers, B.  Florida Pusley Control in Pastures [SS AGR 314].  Gainesville: UF/IFAS Cooperative Extension Service, December, 2009.  http://edis.ifas.ufl.edu/ag320

Hall, D.W., Vandiver, V. and Ferrell, J.A.  Florida Pusley, Richardia scabra L. [an excerpt from Weeds in Florida, SP 37.]   Gainesville: UF/IFAS Cooperative Extension Service, February,  2009.  http://edis.ifas.ufl.edu/fw034 

PlantFiles: Florida Pusley,  Richardia scabra. El Segundo, CA: Dave’s Garden Website, accessed 12/2011. http://davesgarden.com/guides/pf/go/71314/

Sanchez, S. Fairy Cups. In: Steph's Virtual Butterfly Garden (website), [Fort Lauderdale?], 2007.   http://butterflies.heuristron.net/plants/richardia.html