Learn to Identify and Remove Invasive Plants

Coral ardisia is an aggressive invasive with glossy, dark green leaves and clusters of bright red berries in the winter. Photo by Jody Walthall.

Let’s talk about a threat to our nation. The threat is silent, ongoing, happening in our own yards and parks, and threatens our wild and natural areas, both wetlands and uplands. The State of Florida spends around $45 million a year on invasive plant control. The federal government spends an estimated $120 billion dollars a year.

There is something each of us can do in our own yards to address this problem. Let’s look at four plants that occur commonly in our yards of North Florida and South Georgia – coral ardisia, nandina, Chinese privet, and Japanese ligustrum (glossy privet). Learn to recognize these plants and work to remove or control them. All four are listed as Category 1 (the worst) Invasive Plants by the Florida Invasive Species Council.

Coral ardisia has glossy, dark green leaves usually on a vertical stem two to four feet tall. Lower on the stem are clusters of bright red berries in the winter. It is an attractive plant and that is why nurseries sold it and people shared it with each other many years ago. Ardisia spreads from yards into other yards, and then into natural areas, parks, and forests. It grows densely, crowding out native plants on the forest floor.

To remove them, first prune off the berry stems being careful to not drop any on the ground. Place them in bags and into a trash receptacle. Do not try to compost them or put them on the roadside for pickup by the city. They have an extremely high germination rate and will sprout wherever they land. After removing berries, dig all plants with a shovel. Pulling usually results in broken roots remaining in the soil to resprout. Watch for tiny seedlings, especially under the larger plants, and pull these as well.

Nandina is an invasive plant that is very toxic to birds. Photo by Jody Walthall.

Nandina is an old landscape plant with lovely fern like leaves and showy red berries. A classic example of nandina invading a natural area is the wooded land on the south side of Centerville Road near the Betton Road intersection in Tallahassee, where hundreds of them are growing beneath the native tree canopy. In beautiful Thomas County, Georgia, dozens of cedar waxwing birds died after gorging on nandina berries. Cyanide in the berries caused hemorrhaging in their lungs, liver, kidneys, heart, and brain, a terrible way to die. The University of Georgia College of Veterinary Medicine published the findings.

To remove nandina, follow the same procedure as with ardisia. Nandina roots, however, are very tough and difficult to dig. You will need an axe or mattock to cut the roots. If you do not have the strength to dig either nandina or ardisia, at least cut off the berries each year so they cannot spread further. Hiring a professional landscaper is also an option.

Chinese privet is an invasive shrub that can grow up to 25 feet in height. Photo by Jody Walthall.

Chinese privet is a common invasive shrub across North Florida. It has extended its range from N. Carolina to Kentucky, west to Texas, and south to Miami. It is even an alien invasive in Australia and Argentina. It can grow to 25 feet tall. White spring flowers have a strong fragrance, often described as malodorous. For removal, cutting large trunks and painting herbicides on the fresh cut may kill it, but roots may resprout. Though they may be large, plants are shallow rooted and can be dug using a mattock. Roots left in the ground may sprout. Monitor the area and keep digging for total removal.

Japanese ligustrum (Ligustrum lucidum), also known as glossy privet, is a fast-growing tree reaching 40 feet in height with a 35-foot crown spread. Like the Chinese privet, it has showy white malodorous spring blooms. Large clusters of purple/black berries ripen in fall and are popular with birds. The birds disperse the berries through droppings. The Institute of Food and Agricultural Sciences at the University of Florida (UF/IFAS) advises that this plant can be a nuisance, writing, “This plant should be treated with caution, may be recommended for planting, but managed to prevent escape.” Are we to ask the birds to please not eat the berries and spread them into our parks, forests, and yards? In my own yard this year alone, I have pulled up at least one thousand seedlings coming from a neighbor’s tree. This week I discovered another area in my yard where I counted 70 in one square yard!

Japanese ligustrum, also known as glossy privet, is a fast-growing tree that can easily be spread by birds. Photo by Jody Walthall.

As mentioned above, Japanese ligusturm can become a medium sized tree and may require a professional for removal. Homeowners can cut smaller ones and poison the stump with an herbicide with the active ingredient triclopyr, such as Brush-B-Gon. Use a small disposable brush to paint the outer half-inch circumference of the fresh cut stump. Here is a hint for identifying both Chinese privet and Japanese ligustrum – both have oppositely arranged leaves on their stems.

All four of these invasive species alter native plant communities causing ecological damage to natural ecosystems. They represent real threats to our nation’s wild areas, in addition to the nuisance they create in our own yards. Since they came from other parts of the planet, there are few natural insects or diseases in our country to control their spread. Without ongoing control and diligence on the part of homeowners, volunteers, and governmental agencies, the alien plants will eventually spread and crowd out our American native plants, upsetting our complex food webs, and disturbing the balance of nature.

I have started with these four recognizable invasive plants for homeowners to learn about. There are plenty of others lurking about our yards. If you have the physical ability to remove them, go for it. If not, hire a strong neighborhood teenager or pay for professionals. Let’s protect our native natural areas!

Some other invasive plant to remove include Chinese camphor tree, Chinese tallow tree, golden rain tree, Chinese elm, mimosa, cat’s claw vine, Japanese honeysuckle, Japanese climbing fern, air potato vine, skunk vine, and Chinese Wisteria.

Nesting and Overwintering Habitat for Beneficial Insects

While our gardens sleep for the few winter months we have, what happens to the bees, butterflies, and other beneficial insects that we depend upon during the growing season?

Where do they go? How do they survive the winter? Are there things we can do to provide nesting and overwintering habitat?

A ground nest entrance in a patchy lawn.

While it may seem like the insects have vanished for the year, the vast majority of them haven’t actually gone anywhere. They see your garden as a place of protection from the elements and will display a variety of unique strategies to survive the cool winter climate.

Allow fallen leaves to collect in beds and under trees. Photo by Elizabeth Georges.

Most bees and solitary wasps nest beneath the soil in patchy, bare areas of lawn, while others build cavity nests in places like the hollow stems of plants, old beetle burrows, tree snags, or decaying logs. Bumble bee nests are often found in loose undisturbed soil beneath woody plants, tall grasses, or other dense vegetation. Luna moths overwinter in cocoons, snug in an insulated pile of leaves, while hawkmoths burrow and pupate underground. Eastern black swallowtails camouflage their chrysalids as a dried leaf or a broken twig anchored from a dead flower stem. Other insects such as fireflies, spiders, and beetles seek shelter in leaf litter and rock piles or brush. These are just a few examples of the many insects that will take up shelter in the natural features of your yard.

Having a diversity of native plants is a good place to start when adding overwintering elements to your yard. Consider adding shrubs with hollow stems, such as elderberry, pokeweed, oakleaf hydrangea, and leucothoe; and wildflowers such as dotted horsemint, Joe-pye weed, purple coneflower, ironweed, and asters. All of these plants will provide food for wildlife and nesting sites for a variety of stem-nesting bees.

Leave stumps, snags, and fallen logs for cavity nesters. You can build brush piles with twigs and branches. Photo by Elizabeth Georges.

You can start to cut back spent flower stalks in the spring, but don’t cut them to the ground. Leave a variety of heights, eight to 24 inches above the ground. Female bees will use the cut ends to start a nest. The bee larvae will grow through the season, hibernate over the winter, and then emerge the following spring. It’s a yearlong process so the stalks must stay in the garden, otherwise, you are throwing away your next generation of pollinators. If you must cut back your plant material, keep it in the landscape instead of getting rid of it. Bundle it up or create a brush pile in an area out of the way. Insects will still use the plant if it’s cut and moved. The old stalks will eventually decompose after the insects are through with them, adding nutrients back into the soil.

We’ve been trained to think that a tidy expanse of lawn is the goal, but that lawn doesn’t do much for the birds, bees, butterflies, and other creatures that we share our yards with.Retaining and incorporating as many natural features as possible into your landscape, rather than tidying them away, will help increase the availability and quality of nesting and overwintering habitat. Habitats that connect can have a big impact on a neighborhood scale. One small habitat becomes a large habitat that a diversity of beneficial insects and wildlife can use. Consider putting the pruners up, leaving the leaves, and letting the insects do the work for the future success of their generations and your garden alike.

Plant a Diversity of Oaks This Winter

North Florida and South Georgia are blessed with many species of native oak trees. Two species, dwarf live oak and running oak, form thickets from underground runners and may reach heights of only three feet.

Plant swamp chestnut oak to add diversity and bright fall color to your yard. Photo by Donna Legare.

Some oaks have limited distributions in North Florida. Cherry bark oak and chinquapin oak occur only in Gadsden, Liberty, or Jackson counties along the Apalachicola River.

Others have extremely strict soil requirements, occurring only in deep sand of either present day or ancient sand dunes or sea floors. These soils occur from the present-day coastline to north of Bristol and Blountstown. Drs. Robert Godfrey and Herman Kurz, in their book Trees of Northern Florida (1962), describe two types of sand, buff and white, with certain oaks preferring one or the other. Buff sand is common in inland Wakulla County with turkey oak, bluejack oak, and sand-post oak found growing there, among others. Coastal dunes consisting of white sand support Chapman oak and sand-live oak.

Of the 25 oak species native to our area, only about 10 may be found at local garden centers. Others may be obtained by special request. Usually, these ten species can grow on either dry buff sand, moist lowlands, or rich upland soils.

This young white oak was planted in 2018 to add diversity to Mary Kay Falconer’s Betton Hill’s yard. Photo by Mary Kay Falconer.

This young white oak was planted in 2018 to add diversity to Mary Kay Falconer’s Betton Hill’s yard. Photo by Mary Kay Falconer.

Most people think of live oak when planting an oak in our area for good reason. They are long-lived grand trees. But there are other equally stately and beautiful species that should be used more often, such as white oak, swamp chestnut oak (also called basket oak), Shumard oak, and southern red oak. Laurel oak and water oak are quite common in our area. They are often given a bad rap for weak wood, but both can be strong, healthy trees for at least 50 years, meanwhile providing food for insects, birds, and mammals.

In his recent book, The Nature of Oaks (2021), Doug Tallamy discusses the amazing diversity of animals, primarily insects, which depend on oaks. He writes that native oaks in our nation support 534 species of moth and butterfly caterpillars, more than any other group of trees. Ninety percent of these caterpillars are soft, juicy, high protein food for songbirds and their nestlings.

Native oaks harbor more than caterpillars. Acorn weevils, lacebugs, leaf hoppers, walking sticks, tree cattle, tree crickets, and many other species are part of a valuable ecosystem in the canopy over our heads, usually unnoticed by us. This rich diversity of insects becomes the base of a complex food web.

When choosing an oak to add to your landscape, remember that only native species harbor the huge food web in their canopies. A non-native Japanese saw-tooth oak may provide acorns for deer, but the space taken up by the canopy will be a dead zone for other life. Most native insects cannot utilize non-native plants, due to the presence of different chemicals in the leaves. They need native plants with whom they have shared an evolutionary history.

Leaves in the canopy are not the only valuable resource for wildlife. Oak leaves on the ground below an oak decay more slowly than most other tree species. This leaf litter provides housing, food, and humid conditions for up to three years for insects. For example, Tallamy writes that there can be 90,000 springtail insects in a square meter under an oak. Leaf litter mites may be 250,000 per square meter!

The precious leaf litter under your trees is also critical for giant silkmoth reproduction. After eating leaves in the canopy, the caterpillar drops to the ground to spend a year or two as a pupa hidden under the dead leaves. If your lawn grass extends under the canopy, it spells death for the future beautiful imperial or Polyphemus moth.

Three species of oaks are quite common in our region – live oak, water oak, and laurel oak. For a healthy urban/suburban ecosystem, diversity is key; try planting other species of oaks in your yard. Choose the best oak for your yard based on soil and moisture needs. Some species are very adaptable, others are not. Consider white oak, Shumard oak ,and swamp chestnut oak for their stunning fall color. Mature white oak and swamp chestnut oak also have attractive light gray shaggy bark. Southern red oaks are also stately.

Winter is the best time to plant a tree in our region, while the tree is dormant. Doug Tallamy states, “contrary to urban legend, many species of oak grow quite quickly.” Give your tree plenty of space. Plant three or more trees in a small grove for roots to interlock and create a stronger planting for hurricane survival.

Tallamy suggests planting acorns for the healthiest root structure but admits most of us want instant gratification and squirrels will not cooperate and plant them where we want them. The next best method is to plant an inexpensive bare root seedling or whip. These will also grow a healthy root system.

The third option is to purchase a small one-, three- or seven-gallon potted tree. Roots may be circling in the pot and should be spread out in the hole or pruned off. Circling roots can kill a tree after a few years or will not provide a solid foundation in hurricane winds.

Tallamy’s “bottom of the list” option is to plant an expensive three- to four-inch caliper oak from a large container. The root system will be so compromised that the tree will not have a long life. Unfortunately, government codes usually specify planting large trees for instant impact.

This winter, increase the biodiversity of our urban forest; plant some different oaks and become a part of Tallamy’s “Suburbia National Park.”  Remember they must be American native species!