Plant This, Not That

Plant This, Not That

The plants you bring home from garden centers and nurseries may look beautiful in your landscape, but they might be invasive species that could escape your yard and quickly spread into natural areas, becoming an ecological and economic nightmare.  Florida’s climate makes a cozy environment for a variety of plant species, including the non-native ones. To avoid contributing to the problem, homeowners, landscapers, and plant lovers should carefully select alternative sterile cultivars or other native plants. 

The Florida Exotic Pest Plant Council (FLEPPC) created a list of invasive plants that was published every two years through 2019.  Professional botanists and others perform exhaustive studies to determine invasive plants that should be placed on the lists. Invasive plants are termed Category I invasives when they are altering native plant communities by displacing native species, changing community structures or ecological functions, or hybridizing with natives.

In 2020 the Florida Invasive Species Council (FISC) took over this task.  They began by standardizing invasive species terminology.  FISC has adopted the following definitions as described in the publication “Invasive Species Terminology: Standardizing for Stakeholder Education” from the Journal of Extension (Iannone et al. 2020).  For details on the new terminology go to:  https://floridainvasivespecies.org/definitions.cfm.  Words like “exotic”, “alien”, and “naturalized” have been removed from educational material due to individual interpretation concerns. The term “invasive” can only be applied to nonnative species.  Many previous informational publications referred to aggressively growing native plants as invasive.  This use is no longer accepted.  Here are some sample definitions:

  • Invasive: A species that (a) is nonnative to a specified geographic area, (b) was introduced by humans (intentionally or unintentionally), and (c) does or can cause environmental or economic harm or harm to humans.
  • Nuisance: An individual or group of individuals of a species that causes management issues or property damage, presents a threat to public safety, or is an annoyance. Can apply to both native and nonnative species.

For a copy of the current invasive plant species listing, as well as other important list of state and federal noxious and prohibited plants go to:  https://floridainvasivespecies.org/plantlist.cfm

Invasive lantana
Many Lantana camara selections are invasive. Look for a sterile selections to prevent unwanted plant spread. Photo by Beth Bolles, UF IFAS Extension Escambia County.

On Wednesday, September 20, 2023, the Okaloosa County Master Gardener Lecture Series topic will be “Plant This, Not That”.  This program will introduce the invasive plant species that pose an ecological threat to Florida ecosystems and some alternatives that provide a similar aesthetic value. For more information and to register, click on this Eventbrite link.

program info
Learn the plants that can substitute for invasive plants with Sheila Dunning, Commercial Horticulture Agent with UF IFAS Extension Okaloosa County.
My Mexican Petunias are Fuzzy!

My Mexican Petunias are Fuzzy!

Many of the Mexican petunia plants, Ruellia simplex, growing in the landscape along the Gulf Coast are covered in white patches. The leaves appear to be growing fur, actual hairs, much denser than the dust of powdery mildew fungus. Excessive development of leaf trichomes, or surface hairs is referred to as erinea. The “fuzz” is the plant’s response to the feeding of eriophyid mites, also called gall mites. These native tiny, microscopic mites feed on the Mexican petunia leaves and stems, causing the plant to produce the white velvety masses. The distorted tissue provides shelter so the mites can continue to feed without being impacted by the weather or contact pesticide applications. Hot, dry conditions favor mite population increases.  We have had plenty of that.  However, the native mites are not likely to kill the invasive Mexican petunia, so they are not acting as an effective biological control for the plant.

Mexican petunia problems
Mexican petunia damage from the eriophyid mite.

Control of this native eriophyid mite begins with heavy foliage removal. Cutting the plants back to just a few inches above the ground removes the infested portion of the plant. The pruned parts need to be placed in a tightly sealed plastic bag before being sent to the landfill. If the location allows burning on-site, that is an even better option. Remember that these mites can feed on many other plants if allowed to escape.  They have caused galls in crape myrtle, loropetalum, and hollies, as well as, vectoring diseases like rose rosette.

Then comes the tough decision. If the Mexican petunia is not one of the new sterile cultivars should the new growth be protected as it grows back? If you didn’t plant them or don’t remember what they were called when you purchased them, there is still a way to determine whether they are the invasive Mexican petunia or not.  Invasive Mexican petunia produces seed after flowering. Were there any seed pods on the pruned parts? If so, you may consider killing off the entire planting. Several applications of a total vegetation herbicide with surfactant will remove them, leaving you a spot for a new purple flower, maybe a porterweed (Stachytarpheta), verbena or blue salvia.

Blue porterweed can be a substitute for non sterile Ruellia. Photo by Beth Bolles UF IFAS Escambia Extension

If your plants are sterile (have no seed pods), an application of horticultural oil and/or a miticide like abamectin sprayed with each flush of new growth will produce a pretty bed of purple flowers in a short period of time.

Japanese beetle – Be Aware of the Potential Threat, Stay Informed.

Japanese beetle – Be Aware of the Potential Threat, Stay Informed.

Credit: Worrel Diedrick, Florida A&M University

They are known for their voracious feeding habits, targeting a wide range of plants, including ornamentals, fruit trees, and vegetables. I speak of no other than the Japanese beetle (Popillia japonica) an invasive species in the United States, originating from Japan.  

Though reports have been made of Japanese beetle sightings in Florida, there is still not a known established population. However, it’s important to note that the status of Japanese beetles in Florida can change, potentially rapidly, over time. Thus, it is important to be able to identify the species’ host plants and damaged caused. Early detection, monitoring, and swift action can help minimize the potential damage caused by invasive species like Japanese beetles that could potentially have negative impacts on agricultural crops, gardens, and ornamental plants.

Description

The adult Japanese beetle is an attractive pest that is generally metallic green, with bronze or copper-brown wing covers that do not completely cover the abdomen, revealing five patches of white hairs on each side and one pair on the last abdominal segment. These features distinguish Popillia japonica from all other similar looking beetles. In terms of shape, Japanese beetle generally have a broad oval body structure. Notably, the female beetles tend to be larger in size compared to their male counter parts.

Developmental stages usually take place under the soil after the female deposit her eggs. In most instances they complete their life cycle in one year emerging later in the summer months, however this varies based on locations.

Host plants

Japanese beetles have known to have over 300 host plant species; however, some common host plants include maples, soybean, ornamental apple species, plums, peaches, roses, blackberry, raspberry, limes, elms, grapes, and corn. Crepe myrtle and turfgrasses are also host plants.

Damages

Both adults and larvae cause plant damage. Adults feed on the foliage of host plants resulting in skeletonization of the leaves, while larvae feed on the root systems of turf and pasture species, affecting the ability of the plant to uptake nutrient and water from the soil.

Management

If Japanese beetle populations do become established in Florida, it is generally advisable to take measures to manage the population such as physically removing them, using pheromone traps, or other integrated pest management strategies. Chemical recommendations are not currently available in Florida since this beetle is not reported as a pest problem. However, it is always advisable to contact your Local Extension office for recommendations. The United States Department of Agriculture (USDA) has also provided some useful information on the Japanese beetle in their homeowner’s handbook titled “Managing the Japanese Beetle: A Homeowners Handbook’’.

For the most current and accurate information specific to Japanese beetles in Florida management and species identification, consult your extension office. Supporting document can also be found by clicking the link below.

Useful resources:

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