If you’ve more than glanced at the plants along the roadside or questioned the vines creeping through your neighborhood, it is likely that you are familiar with the encroachment of invasive plants into our natural spaces. Our manicured spaces are at just as much risk as our natural spaces, though. Invasive plants have long been on the market, sometimes even encouraged to be planted in our yards, such is the case for Mexican Petunia. Understanding the risk of these unpredictable invasive plants and identifying those we are likely to come across at a garden center is essential to preserving our ecosystems—inside and outside of our yards.  

Executive Order 13112 defines invasive species as a nonnative species “whose introduction does or is likely to cause economic or environmental harm or harm to human health”. These introductions may be a result of accidental transportation, pet trade, or ornamental trade. 

Ornamental trade allows plant enthusiasts to grow and cultivate aesthetically and functionally fascinating species that wouldn’t otherwise be available in their region. These species, however, pose a threat to our ecosystems when they are at risk of escaping containment, spreading rapidly, and overtaking other species. A clear example of this occurred in 1884 when Eichhornia crassipe, more commonly known as water hyacinth, was brought to the United States for the World’s Industrial and Cotton Exposition in New Orleans, Louisiana where each attendee was given the plant as a souvenir. It wasn’t long until it made it to Florida, where its beautiful purple flowers overtook lawns, leading the excess plants to be discarded into the St. John’s River from where they continue to spread, block sunlight, deplete oxygen, and destroy native fish and plant habitats and populations. 

Where else can we turn for lovely flowers if not water hyacinth? The Impatiens genus offers lovely flowers, but be cautious of the species you select as certain species have a high risk of invasion. For example, the commonly planted Impatiens balsamina is not invasive and offers lovely stacked arrangements of purple, red, and pink flowers while the Impatiens walleriana species—also providing clusters of small warm flowers—pose a high invasion risk with their rapid growth. 

Our yards may be overtaken by the rapid growth of the Arachis pintoi that also has a high invasion risk. Our yards and pollinators can benefit significantly from the bright perennial peanut groundcover with its dainty orange flowers that sprinkle the earth. However, it is imperative that we carefully select which species is planted as the most commonly cultivated Arachis glabrata is not invasive and safe to plant, unlike the aforementioned Arachis pintoi. 

While identifying each species may be difficult, it is imperative to avoid a garden, yard, or landscape takeover as frequently seen with popular landscape plants such as lantana. This plant produces the most breathtaking variety of blooms and differently colored florets but can easily dominate the space they’re in, especially the Lantana strigocamara species. To avoid looking for each specific species name, just know to avoid the “Lucky” cultivars as this potential invader is only mostly sterile, but not 100%. Instead, select from the “Bloomify” options. 

It is not just the brightly flowering plants we need to be wary of. The frequently sought-after snake plant, Sansevieria trifasciata, with its striking green and yellow coloration poses a high invasion risk as well. This species is native to tropical West Africa and is tolerant of a wide range of conditions, making it an ideal species for both beginner gardeners as well as landscape take-overs. 

Garden take-overs are frequently pioneered by the deep purple ground cover that is wandering dude or other plants in the Tradescantia genus. The small white flowers of Tradescantia fluminensis are invasive, as is the oyster plant Tradescantia spathacea with its large purple leaves, and the variegated silvery leaves of Tradescantia zebrina. The most commonly seen purple queen, Tradescantia pallida, is still undergoing assessment, so it is advised to proceed your plantings with caution. 

One species that does not need any further assessment is the massively prolific Imperata cylindrica, or cogongrass. This pyrogenic, rapidly-growing grass has long invaded the Southeast and has now made its way into our nurseries and box stores despite being a prohibited species. The Red Baron or Japanese Bloodgrass—so named for its striking red tips—was selected to be sterile but this cultivar still spreads rapidly by rhizomes and can even revert back to its typical green, highly invasive state. 

When selecting flowers to bring some vibrancy into your garden, groundcovers to provide some soil stability, grasses to add some texture to your landscape, or any other plant that may have caught your eye, it is important that you do your research and know just what you’re introducing into your yard. Each of the invasion-level identifications used in this blog was provided by the UF IFAS Assessment of Non-Native Plants in Florida’s Natural Areas, a valuable resource to consult regarding invasion risk and status as well as plant recommendations. Additionally, while that resource may tell you which plants to avoid, UF IFAS Extension’s Florida Friendly Landscaping™ Program will provide you with invaluable guidelines of which plants to use for a healthy, low-maintenance, and wildlife and pollinator-supporting yard. Plants are incredibly fascinating organisms that can easily provide striking aesthetics and interest, but we must be cautious about those which we are selecting to carry this out with.

Post contributed by Ellie Whitaker, UF CALS intern with the UF/IFAS Extension office in Alachua County.

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