Gardening in the Panhandle LIVE Program Summary: Invasive Species

Gardening in the Panhandle LIVE Program Summary: Invasive Species

Invasive species are all around us, from invasive plants like cogongrass to invasive amphibians like Cuban tree frogs to invasive insects like red imported fire ants.  These species affect our ecosystems by outcompeting native species for nutrients or food and other precious resources.  To help with the management of these noxious organisms, the October 2021 edition of Gardening in the Panhandle LIVE educated the public on invasive species.  The highlights from the webinar are listed below.

Cogongrass dominating the landscape. Photo credit: Charles T. Bryson, USDA Agricultural Research Service, Bugwood.org.

Invasive Species Education

For general invasive species terminology please visit.  Invasive Species Terminology: Standardizing for Stakeholder Education

Here’s a great resource to help educate the public about invasive plant species.  Florida Invasive Plant Education Initiative

The University of Florida has developed a comprehensive list of invasive plant species.  Assessment of Non-Native Plants in Florida’s Natural Areas

Invasive Species Control

Cogongrass Control: Cogongrass (Imperata cylindrica) Biology, Ecology, and Management in Florida Grazing Lands

Bamboo Control: Bamboo Control

Chinese Tallow (Popcorn Tree) Control: Natural Area Weeds: Chinese Tallow (Sapium sebiferum L.)

Armadillo Management: Baiting the Nine-Banded Armadillo

Dollarweed Control: Pennywort (Dollarweed) Biology and Management in Turf

Doveweed Control: Biology and Management of Doveweed (Murdannia Nudiflora) in Ornamental Crop Production

 

Controlling Cogongrass

Controlling Cogongrass

Over the last decade or so, the Panhandle has been overrun, and I don’t just mean by the summer beach traffic.  Rather, by an aggressive, exotic perennial grass that quickly displaces all native species, is not useful as a forage to wildlife or livestock, can spread by roots or seeds, and has no natural enemies.  If you own property in the Panhandle or spend any amount of time on its roads, chances are you have become acquainted with this worst of invasive species, Cogongrass (Imperata cylindrica).

A native of Southeast Asia, cogongrass was introduced into the US in 1912 around Mobile, AL as a hitchhiker in orange crate packing.  Then the 1920s, 30s, and 40s, it was intentionally introduced from the Philippines into other Gulf Coast states, including Florida, as a potential pasture forage for livestock.  Since then, cogongrass has become one of the most economically and ecologically important invasive species in the US and worldwide, infesting nearly 500 million acres and is now found on every continent.

Cogongrass in Calhoun County, FL. Photo courtesy of Daniel Leonard.

Cogongrass is easily identified in late spring, when the grass throws easily spotted fluffy, white-colored seedheads above the mats of grass beneath.  Additionally, patches of cogongrass are almost always noticeably circular in nature, radiating out indefinitely from the initial infestation.  A closer inspection of the grass will reveal light green leaves up to 4’ in length, with an off-center, silvery colored midrib (the primary leaf vein that runs from the base of the leaf to the tip) and serrated leaf edges.   Underground, cogongrass exhibits a dense underground root system that can reach as deep as 4’.  This feature is the primary reason cogongrass outcompetes other plants, withstands any drought, fire, or soil condition thrown at it, aids in its resistance to herbicide activity, and generally makes it very difficult to manage.

The first step in managing cogongrass is prevention.  If your property or the property you manage doesn’t have cogongrass, do everything you can to keep it that way.  While the species can spread distances through seed dispersal, it is much more frequently moved around by fragmented rhizomes hitching a ride on equipment.  If you or a contractor you’ve hired are working in or around an area with cogongrass present, avoid disturbing it with equipment and be diligent in monitoring the site for outbreaks following the job’s completion.

If you find cogongrass on your property, effectively eradicating it requires patience, persistence, and several years’ worth of herbicide applications.  Currently, of the hundreds of herbicides available for purchase, only two chemistries have been proven to be very effective in destroying cogongrass, impazapyr (Arsenal, Stalker, etc.) and glyphosate (Roundup, Cornerstone, etc.).

  • Imazapyr is an extremely effective non-selective, residual herbicide that controls a wide variety of weed species, including cogongrass. Just one or two applications of imazapyr can provide 18-24 months of effective cogongrass control, with follow up treatments required as needed after that.   However, Imazapyr has a major downside that limits its use in many settings.  Because it is a non-selective herbicide with significant soil residual activity, it cannot be used around the root zones of desirable plants.  Oaks, other hardwood trees, and most landscape plants are especially sensitive to imazapyr.  This herbicide is best limited to use in fields, waste/fallow areas, natural areas, and monoculture pine plantations – it is not appropriate in most residential and commercial landscapes.
  • The other option, glyphosate is a non-selective herbicide with no soil residual activity. It is often a better option where severe injury or death of desirable hardwood trees and ornamental plants cannot be tolerated.  However, due to its lack of residual soil activity, glyphosate applications on cogongrass patches will need to be repeated on an annual or biannual basis for up to five years for eradication of the infestation.

*Regardless of which herbicide you choose, controlling cogongrass is a multi-year affair requiring diligence and patience. 

For more information on cogongrass and for specific herbicide recommendations and application rates/timing for your site, please contact your local UF/IFAS County Extension Office.

 

Landscape  Q & A

Landscape Q & A

On August 12, 2021, our panel answered questions on a wide variety of landscape topics. Maybe you are asking the same questions, so read on!

Ideas on choosing plants

What are some perennials that can be planted this late in the summer but will still bloom through the cooler months into fall?

Duranta erecta ‘Sapphire Showers’ or ‘Gold Mound’, firespike, Senna bicapsularis, shrimp plant, lion’s ear

Where can native plants be obtained?

Dune sunflower, Helianthus debilis. Photo credit: Mary Salinas UF/IFAS Extension.

Gardening Solutions: Florida Native Plants  – see link to FANN: https://gardeningsolutions.ifas.ufl.edu/plants/ornamentals/native-plants.html

What are some evergreen groundcover options for our area?

Mondo grass, Japanese plum yew, shore juniper, ajuga, ferns such as autumn fern.

What are some ideas for partial morning sun butterfly attracting tall flowers to plant now?

Milkweed, salt and pepper plant, swamp sunflower, dune sunflower, ironweed, porterweed, and salt bush.

I’m interested in moving away from a monoculture lawn. What are some suggestions for alternatives?

Perennial peanut, powderpuff mimosa, and frogfruit.

We are new to Florida and have questions about everything in our landscape.

Florida-Friendly-Landscaping TM Program and FFL Web Apps: https://ffl.ifas.ufl.edu/

https://ffl.ifas.ufl.edu/resources/apps/

UF IFAS Gardening Solutions: https://gardeningsolutions.ifas.ufl.edu/

What are some of the top trends in landscaping today?

Houseplants, edible gardens, native plants, food forests, attracting wildlife, container gardening, and zoysiagrass lawns

Edibles

Artwork broccoli is a variety that produces small heads. Photo credit: Mary Salinas UF/IFAS Extension.

What vegetables are suitable for fall/winter gardening?

Cool Season Vegetables: https://gardeningsolutions.ifas.ufl.edu/plants/edibles/vegetables/cool-season-vegetables.html

North Florida Gardening Calendar: https://edis.ifas.ufl.edu/publication/EP451%20%20%20

Florida Vegetable Gardening Guide: https://edis.ifas.ufl.edu/publication/vh021

How can I add herbs to my landscape?

Herbs in the Florida Garden: https://gardeningsolutions.ifas.ufl.edu/plants/edibles/vegetables/herbs.html

My figs are green and hard. When do they ripen?

Why Won’t My Figs Ripen: https://www.lsuagcenter.com/profiles/rbogren/articles/page1597952870939

What is best soil for raised bed vegetable gardens?

Gardening in Raised Beds: https://edis.ifas.ufl.edu/publication/EP472

And there are always questions about weeds

How can I eradicate cogongrass?

Chamber bitter is a troublesome warm season weed in our region. Photo credit: Brantlee Spakes Richter, University of Florida, Bugwood.org

Cogongrass: https://edis.ifas.ufl.edu/publication/WG202

Is it okay to use cardboard for weed control?

The Cardboard Controversy: https://gardenprofessors.com/the-cardboard-controversy/

What is the best way to control weeds in grass and landscape beds?

Weed Management Guide for Florida Lawns: https://edis.ifas.ufl.edu/publication/EP141

Improving Weed Control in Landscape Planting Beds: https://edis.ifas.ufl.edu/pdf/EP/EP52300.pdf

Landscape practices

Can ground water be brackish and stunt plants?

Reclaimed Water Use in the Landscape: https://edis.ifas.ufl.edu/publication/ss545

How can I prevent erosion from rainwater runoff? 

Stormwater Runoff Control – NRCS: https://www.nrcs.usda.gov/wps/portal/nrcs/detail/national/water/?cid=nrcs144p2_027171

Rain Gardens: https://gardeningsolutions.ifas.ufl.edu/design/types-of-gardens/rain-gardens.html

And https://gardeningsolutions.ifas.ufl.edu/pdf/articles/rain-garden-manual-hillsborough.pdf

What is the best time of the year to propagate flowering trees in zone 8B?

Landscape Plant Propagation Information Page – UF/IFAS Env. Hort: https://hort.ifas.ufl.edu/database/lppi/

Which type of mulch works best on slopes greater than 3 percent?

Landscape Mulches: How Quickly do they Settle?: https://edis.ifas.ufl.edu/publication/FR052

When should bulbs be fertilized?

Bulbs and More – UI Extension: https://web.extension.illinois.edu/bulbs/planting.cfm

Should I cut the spent blooms of agapanthus?

Agapanthus, extending the bloom time: https://gardeningsolutions.ifas.ufl.edu/plants/ornamentals/agapanthus.html

http://blogs.ifas.ufl.edu/wakullaco/2020/10/07/extending-bloom-time/

Plant questions

Monarch caterpillar munching on our native sandhill milkweed, Asclepias humistrata. Photo credit: Mary Salinas, UF IFAS Extension.

I planted native milkweed and have many monarch caterpillars. Should I protect them or leave them in nature?

It’s best to leave them in place. Featured Creatures: Monarch Butterfly: https://edis.ifas.ufl.edu/pdf/IN/IN780/IN780-Dxyup8sjiv.pdf

How does Vinca (periwinkle) do in direct sun? Will it make it through one of our panhandle summers? Can I plant in late August?

Periwinkles  and  No more fail with Cora series: https://gardeningsolutions.ifas.ufl.edu/plants/ornamentals/periwinkles.html#:~:text=Plant%20your%20periwinkles%20where%20they,rot%20if%20irrigated%20too%20frequently.

Insect and disease pests

What to do if you get termites in your raised bed?

The Facts About Termites and Mulch: https://edis.ifas.ufl.edu/publication/IN651

How to combat fungus?

Guidelines for ID and Management of Plant Disease Problems: https://edis.ifas.ufl.edu/publication/mg442

Are there preventative measures to prevent diseases when the humidity is very high and it is hot?

Fungi in Your Landscape by Maxine Hunter: http://blogs.ifas.ufl.edu/marionco/2020/01/16/fungi-in-your-landscape/

 

If you missed an episode, check out our playlist on YouTube https://www.youtube.com/watch?v=bp0HfdEkIQw&list=PLhgoAzWbtRXImdFE8Jdt0jsAOd-XldNCd

 

Gardening in the Panhandle LIVE Program Summary: Invasive Species

Solutions for Cogongrass!

Cogongrass dominating the landscape. Photo credit: Charles T. Bryson, USDA Agricultural Research Service, Bugwood.org.

Cogongrass dominating the landscape. Photo credit: Charles T. Bryson, USDA Agricultural Research Service, Bugwood.org.

A U.S. Forest Service grant is again available to assist non-industrial private landowners with the cost of controlling cogongrass. Applications will be accepted starting October 15, 2015. The program reimburses landowners for 50% of the cost for two consecutive years with a maximum reimbursement of $10,000 for each year.

Cogongrass is one of the worst invasive plant species in Northwest Florida as it marches through natural areas and literally chokes out our desirable native vegetation as it goes. The underground rhizomes continually expand patches of the grass in every direction and its prolific seed production carries infestations to new areas.

Note the off center midrib along the leaf blade. Photo credit: Chris Evans, Illinois Wildlife Action Plan, Bugwood.org.

Note the off center midrib along the leaf blade. Photo credit: Chris Evans, Illinois Wildlife Action Plan, Bugwood.org.

There are several ways to accurately identify cogongrass. The leaf blades are flat with serrated edges and tend to be yellowish-green in color. The midrib which runs lengthwise up each leaf blade is white and is distinctly off-center. The seed head which arises in the spring is a fluffy white plume. Since it spreads through rhizomes, cogongrass is often seen in expanding circular patches.

The fluffy white plume of the seedhead. Photo credit: Chris Evans, Illinois Wildlife Action Plan, Bugwood.org.

The fluffy white plume of the seedhead. Photo credit: Chris Evans, Illinois Wildlife Action Plan, Bugwood.org.

 

 

 

 

 

If you need assistance with the identification of cogongrass, please consult your local Extension office.

For more information:

Cogongrass Treatment Cost-Share Program

Cogongrass (Imperata cylindrica) Biology, Ecology, and Management in Florida Grazing Lands