Edis flowering weed seed shapes

Abrus precatorius

High-climbing, perennial, woody vine with slender herbaceous branches. Alternate, stalked leaves, 5-13 cm long, even-pinnately compound with 5-15 pairs of oblong leaflets, to 1.8 cm long with entire margins. Small pea-shaped flowers, white, pink or reddish, in clusters at leaf axils. Flowers in summer. Fruit a short, oblong pod, with 3-8 shiny hard seeds, 6-7 mm long, red with black bases. Seeds extremely poisonous to livestock and humans.

Habitat

Able to colonize a wide variety of habitats – xeric hammock, coastal uplands, flatwoods, hydric hammock, disturbed sites

Comments

Established in central and south Florida. Difficult to eradicate and increases following fire. Seeds dispersed by birds.

Control Methods

  • Manual: Manual: Hand removal effective on small scale
  • Chemical: Basal bark (10% triclopyr ester) for larger stems, or foliar (5% glyphosate). [IFAS]
  • Biological: NA

Control Notes

Note: Remove seed pods if possible. Site must be revisited several times to pull seedlings. Fall applications most effective.

References

IFAS, Center for Aquatic and Invasive Plants. 2013. Rosary Pea. http://plants.ifas.ufl.edu/node/23#more. Accessed on December 2, 2013.

Langeland, K.A., J.A. Ferrell, B. Sellers, G.E. MacDonald, and R.K. Stocker. 2011. Integrated management of non-native plants in natural areas of Florida. EDIS publication SP 242. University of Florida, Gainesville, Florida.

Langeland, K.A., H.M. Cherry, C.M. McCormick, K.C. Burks. 2008. Identification and Biology of Non-Native Plants in Florida’s Natural Areas-Second Edition. IFAS Publication SP 257. University of Florida, Gainesville.

Managing Weeds in Florida Lawns

A weed is a plant in the wrong place or one that you do not want in your turfgrass. The first step in considering any type of weed control is to appropriately identify the weed. Control without weed identification may well create more issues, including turfgrass damage or death.

There are several types of turfgrass weeds based on growth habit and life cycle. Growth habit weeds include the following:

  • Broadleaves—Two seed leaves at germination, true leaves with net-like veins, and generally showy flowers; clover, beggarweed, matchweed, etc.
  • Grasses—One seed leaf, hollow rounded stems with joints and parallel veins in their true leaves; crabgrass, annual bluegrass, torpedograss, etc.
  • Sedges/Rushes—Sedges have triangular-shaped solid stems. Rush stems are round and solid. Both prefer moist habitats; yellow and purple nutsedge, etc.

Life cycle weeds include the following:

  • Annuals—life cycle is completed in one growing season.
  • Biennials—life cycle is completed in two growing seasons; vegetative growth in the first growing season and flowering in the second.
  • Perennials—life cycle is completed in three or more years.

The most successful weed control is based on proper turfgrass management practices that are used to create a dense and healthy yard. Consider the first of nine Florida-Friendly Landscaping TM principles: right plant, right place. Match the turfgrass variety with the site conditions of sun and shade. All turfgrasses, even those that are shade tolerant, require a minimum of five to six hours of sun each day. Bermudagrass and bahiagrass do not thrive in any shade conditions, which makes them more susceptible to weeds.

Proper cultural practices are required for dense turf to be capable of preventing weed infestations. Cultural practices include fertilization, watering, mowing, and pest control. Over and underperforming any of these practices increase the likelihood of weed invasion.

Both foot and vehicle traffic can damage turfgrass, which, again, is an invitation for weeds. Soil compaction and excessive water saturation should be corrected. Pests that disrupt/create holes in the soil surface, such as mole crickets and armadillos, create open areas, which encourage weed populations.

Lynn Barber, Agent

University of Florida/IFAS Extension, Hillsborough County

Lynn Barber, Agent, University of Florida/IFAS Extension, Hillsborough County, is responsible for educating residents on the nine principles of the Florida Friendly LandscapingTM program. These principles include right plant right place, water efficiently, fertilize appropriately, mulch, attract wildlife, manage yard pests responsibly, recycle, reduce stormwater runoff, and protect the waterfront. Barber is past president of the Florida Association of Natural Resource Extension Professionals and has received numerous awards for programming, publications, and television and radio segments. As a Master Gardener, she has given back thousands of hours in environmental horticulture education to the community.

Prevention is easier than control. Consider a groundcover instead of turfgrass in heavily-shaded areas. Scout your turfgrass regularly to identify potential weed and pest issues. Avoid parking, driving, and excessive walking on your yard. Water appropriately, ½–¾ inch per event, which includes rainfall. Fertilize appropriately, two to three times per year, and if you leave your grass clippings on your turfgrass, you can decrease fertilizations to one to two times per year.

Weeds can be controlled using the following methods:

  • Mowing—at the proper height and frequency for your turfgrass variety, remove no more than 1/3 of the leaf blade and mow when turfgrass is dry.
  • Hand pulling—if few weeds are present, this can be less time-consuming and easier than some options; remove roots, may need a trowel or shovel.
  • Herbicides—any chemical that damages or kills a plant, must follow the label instructions, the label is the law. Herbicides can be selective (control specific weeds without damaging other plants), nonselective (control/kill all plants), contact (affect only the portion of the plant tissue contacted by the herbicide), and systemic (kill plant over several days). Herbicides can be pre-emergence or postemergence. Pre-emergence are mainly used to control annual grasses (crabgrass, annual bluegrass) and some annual broadleaf weeds. This product is used before weed seed germination. Post-emergence herbicides are used on weeds that have emerged. It is easier to control younger versus older weeds.

For additional information on controlling weeds in your lawn, weed control prior to turf establishment and in established turfgrass areas, application procedures and general pesticide information, please see the University of Florida publication, Weed Management Guide for Florida Lawns, by J. Bryan Unruh, Ramon G. Leon, Barry J. Brecke, and Laurie E. Trenholm at: edis.ifas.ufl.edu/ep141, from which this article was adapted.

As always, follow the landscape or architectural control procedures in your deed restrictions before making changes. For more information about the nine principles of the Florida-Friendly Landscaping™ Program, or for assistance with gardening-related questions, contact your local Extension office and/or visit the University of Florida website: solutionsforyourlife.com or edis.ifas.ufl.edu.

Landscape Performance, Flowering, and Female Fertility of Eight Trailing Lantana Varieties Grown in Central and Northern Florida

Trailing lantana [Lantana montevidensis (Spreng.) Briq.] is a low-growing, woody ornamental valued for its heat and drought tolerance and repeat blooming of purple or white flowers throughout much of the year. In 2011, trailing lantana was predicted to have high invasion risk by the UF-IFAS’s assessment of non-native plants in Florida, and therefore it was no longer recommended for use. All cultivars fall under this designation unless proven otherwise. Eight trailing lantana varieties were obtained from wholesale growers or naturalized populations found in Texas and Australia. Plants were propagated vegetatively, finished in 4-inch pots, and planted in field trials located in central (Balm) and northern (Citra) Florida. Throughout the 24-week study from June to November, mean plant quality was between 4.4 and 4.7 (on a 1 to 5 scale) for U.S. varieties and 3.9 for the Australian form. Mean flowering was between 4.1 and 4.5 (on a 1 to 5 scale) for U.S. trailing lantana varieties and 3.5 for Australian trailing lantana. Australian trailing lantana differed from other U.S. varieties tested, being smaller in size, more sensitive to cold, and having a high female fertility index (producing abundant fruit with viable seed per peduncle). Our findings indicate that some U.S. varieties of trailing lantana are unlikely to present an ecological threat and merit consideration for production and use.

Abstract

Trailing lantana [Lantana montevidensis (Spreng.) Briq.] is a low-growing, woody ornamental valued for its heat and drought tolerance and repeat blooming of purple or white flowers throughout much of the year. In 2011, trailing lantana was predicted to have high invasion risk by the UF-IFAS’s assessment of non-native plants in Florida, and therefore it was no longer recommended for use. All cultivars fall under this designation unless proven otherwise. Eight trailing lantana varieties were obtained from wholesale growers or naturalized populations found in Texas and Australia. Plants were propagated vegetatively, finished in 4-inch pots, and planted in field trials located in central (Balm) and northern (Citra) Florida. Throughout the 24-week study from June to November, mean plant quality was between 4.4 and 4.7 (on a 1 to 5 scale) for U.S. varieties and 3.9 for the Australian form. Mean flowering was between 4.1 and 4.5 (on a 1 to 5 scale) for U.S. trailing lantana varieties and 3.5 for Australian trailing lantana. Australian trailing lantana differed from other U.S. varieties tested, being smaller in size, more sensitive to cold, and having a high female fertility index (producing abundant fruit with viable seed per peduncle). Our findings indicate that some U.S. varieties of trailing lantana are unlikely to present an ecological threat and merit consideration for production and use.

Trailing lantana [Lantana montevidensis (Spreng.) Briq.] is a low-growing, woody shrub or sprawling groundcover native to tropical areas of South America. The leaves are simple, opposite, rugose, ovate in shape, with dentate margins and a pungent odor when crushed. The attractive umbel inflorescences are typically lavender in color with varying degrees of white and/or yellow in the center of corolla tubes. Flowers are followed by an infructescence of ellipsoid drupes turning from green to purple when ripe (Dehgan, 1998).

As early as 1825, the species was described by the German botanist Curt Polycarp Joachim Sprengel (Johnson, 2007, 2009). It has since escaped cultivation and is considered invasive in many subtropical ecosystems from Hawaii, Australia, and the Southeast United States. The invasiveness of trailing lantana is attributed to several factors, including 1) its ability to produce large amounts of fruit that are dispersed by birds, 2) the presence of an underground storage organ (xylopodium) facilitating its resilience to fire, drought, and herbicide, 3) its potential to produce two embryos per seed (apomixis) that germinate under a range of conditions, and 4) its ability to spread vegetatively (O’Donnell, 2002). Due to its rapid expansion and colonization of native lands and improved pastures in Australia, trailing lantana is a restricted invasive prohibited for use by the Queensland Biosecurity Act of 2014 (Johnson, 2007, 2009; Munir, 1996; O’Donnell, 2002). In the United States, it has escaped cultivation in seven states, including Alabama, California, Florida, Georgia, Hawaii, Louisiana, and Texas [U.S. Department of Agriculture, National Resources Conservation Service (USDA, NRCS), 2020]. In Florida, herbarium vouchers have documented its escape in 18 counties (Wunderlin et al., 2020).

To date, trailing lantana has not been listed as a Category I or II invasive plant by Florida’s Exotic Pest Plant Council (FLEPPC, 2019). However, based on a predictive test, the University of Florida/Institute of Food and Agricultural Sciences’ (UF/IFAS) Assessment of Non-Native Plants in Florida’s Natural Areas does not recommend its use in northern, central, or south Florida, because it has a high invasion risk (UF/IFAS Assessment, 2020a). The predictive tool used to make this conclusion is a weed risk assessment protocol consisting of 49 questions that address the history of the species, along with its biogeography, life history traits, and ecology (Lieurance et al., 2016). Each question receives a numerical score between −3 and 5 points, and conclusions are made based on the cumulative score. Any score greater than 6 means a high risk of invasion. Trailing lantana received a score of 29 and is therefore not recommended for use in Florida (UF/IFAS Assessment, 2020b). Specifically, the species scored a value greater than 0 for 25 of the 49 questions, with heavier weighted scoring designated due to it being a weed of agriculture (4 points), a weed of environmental harm (4 points), a garden weed (2 points), a congeneric weed sharing the genus of the highly invasive Lantana camara L. (2 points), and the documented naturalization beyond its native range (2 points). In Florida, all cultivars fall under this classification unless proven otherwise through an internally approved UF/IFAS Infraspecific Taxon Protocol (ITP) evaluation. This protocol consists of 12 questions to determine 1) if the taxon displays invasive traits that cause greater ecological impact than the wild type or resident species and if it can be readily distinguished; and 2) the fecundity of the taxon and its chances of regression or hybridization to characteristics of the resident/wild type species (Lieurance et al., 2016).

Interestingly, in Australia two forms of trailing lantana have been reported that differ in their ability to produce fruit (Johnson, 2007, 2009). Steppe et al. (2019) obtained a permit to import germplasm from the fruiting Australian form into the United States. They also collected different U.S. forms sold from various nurseries in Florida and a naturalized form from Texas. A total of eight different varieties of trailing lantana were evaluated for morphological and cytological distinctions. It was discovered that Australian trailing lantana differed morphologically and cytologically from the U.S. varieties (Steppe et al., 2019). Most noticeably, leaves of Australian trailing lantana were smaller with fewer leaf serrations, distinct serrate-crenate margins, and less appressed hairs. Also, well-developed, stainable pollen grains were observed in the anther sacs of the Australian trailing lantana but absent in U.S. varieties. Finally, the Australian trailing lantana was determined to be a tetraploid, but all U.S. varieties evaluated were triploids. The current study was conducted to explore the landscape performance, flowering, and female fertility of these eight trailing lantana varieties planted in replicated field trials at two locations in Florida.

Materials and Methods

Plant material

Eight sources of trailing lantana were identified for use in this study as described by Steppe et al. (2019). Five of the plant sources were from nurseries based in Florida (Hatchett Creek Farms, Gainesville; Costa Farms, Miami; Riverview Flower Farm, Riverview; and American Farms, Naples). One was a leading international cooperative (Proven Winners, Sycamore, IL); one was from a naturalized area in Houston, TX; and another one was from a naturalized area in Queensland, Australia (Table 1). Australian trailing lantana plants were destroyed after completion of the study. Plants were propagated at the Gulf Coast Research and Education Center (GCREC) in central Florida. Cuttings with 3–5 nodes were dipped in 2000 ppm indole-3-butyric acid talc and rooted under mist. After 4 weeks, rooted cuttings were finished in 4-inch pots filled with a peat-based soilless medium (Fafard 2P; Sun Gro Horticulture, Agawam, MA) and planted in full-sun field conditions.

Source and flower characteristics of eight trailing lantana [Lantana montevidensis (Spreng.) Briq.] varieties evaluated for landscape performance, flowering, and female fertility.