Knowledge Is Key When Dealing with These Plant Pests

“Familiarity breeds contempt” according to Aesop, the 6^th century B.C. philosopher and children’s author.

That approach may be correct as applied in the story of the Fox and the Lion, where the lion was outwitted by the sly fox. In managing a home landscape, especially in spring, the exact opposite is true.

Ignorance now may cause extra work later. This is especially true when controlling exotic invasive plants.

While easily identified by their blooms and fruit later in the year, knowing their leaf characteristics will help identify them early so they can be removed. Two of the most common are Lantana and Mexican petunia.

Lantana (Lantana camara) is a woody shrub native to tropical zones of North and South America. It flowers profusely throughout much of the growing season.

It will produce attractive blooms soon, but the invasive potential and toxic leaves of Lantana are a problem. Recognizing its leaves will permit early removal.

Because of the plant’s ornamental nature, many different flower colors exist, but the most frequent color combinations are red and yellow along with purple and white. Lantana is commonly found in naturalized populations throughout the southeastern United States from Florida to Texas.

The textured leaves droop and have veins coming off a central stem. Its saw-toothed edges are contrasted by the pale branches with fine hairs.

It is currently ranked as one of the top ten most troublesome weeds in Florida and has documented occurrences in 58 of 67 counties. Curiously, despite the bad reputation it is still found in home and commercial landscapes.

As part of its arsenal of conquest, Lantana produces allelochemicals or plant toxins in its roots and stems. These allelochemicals have been shown to either slow the growth of other plants or totally remove them.

Some of these same chemicals give Lantana an acrid taste and deter insects or other animals from consuming the leaves. Of importance to pet and livestock owners, these leaf toxins are damaging to animals.

Although Lantana’s leaves are poisonous to mammals, its berries are not. Birds readily consume the fruit and are responsible for much of the seed’s distribution over wide areas.

Mexican petunia (Ruellia simplex) is a native of Mexico, but also the Antilles and parts of South America. Its tolerance of varying landscape conditions makes it a common choice for difficult to plant areas and has contributed to its popularity and frequent use.

The dagger-like leaves and bright red stems of the Mexican petunia are an easy way to identify this popular, but invasive plant. A sterile cultivar purchased from a nursery is a far better choice for adding color to the home landscape.

Mexican petunia tolerates shade, sun, wet, dry, and poor soil conditions. It is a prolific bloomer with flowers in shades of purple and pink peaking in the summer, but with the potential to also bloom in spring and fall in some parts of Florida.

Its dagger-like leaves are upright and longer than wide. The edges are irregular and are contrasted against the red branches.

Environmental tolerance, abundant seed production, and an ability to easily grow from plant cuttings have all promoted its spread into natural areas bordering developments. The Mexican petunia has been credited with “altering native plant communities by displacing native species, changing community structures or ecological functions, or hybridizing with natives” according to the Florida Exotic Pest Plant Council in 2011.

Given the continued popularity of both species, plant breeders have developed sterile, non-reproducing cultivars which do not have the negative characteristics of these problem plants.

Catching and removing early (like NOW) will prevent them from producing seeds and increasing their presence. In these cases, familiarity results in time to do other activities.