Science struggles against tenacious pusley
Kudzu, Old World climbing fern, and tropical soda apple are
all widely known as invaders which were introduced into the region from faraway
and exotic locations. Each has its own story of how it arrived here and escaped
into a welcoming environment.
Once established, these and other alien plant interlopers
have aggressively pushed out native species and changed the landscape. Wildlife
habitats have been altered and millions, if not billions, of dollars have been
spent in an effort to control these destructive intruders.
However, not all plants with aggressive and intrusive
characteristics are offshore invaders. Brazil pusley, Richardia brasiliensis,
is an excellent example of a homegrown (despite its name) vegetative
conquistador with a propensity to overtake less dominant species.
Like its relative Florida pusley, this plant is a low
growing with leaves which are symmetrically located on the opposite side of the
stem. The stems are hairy and can be up to 30 inches long in extreme examples.
Unlike Florida pusley, Brazil pusley is a perennial. Its
roots penetrate into the subsoil which makes it difficult to remove completely.
The leaves can be almost smooth to rough on both the upper
and lower surfaces. They may reach 2.5 inches in length and tend to be oval to
The blooms are usually white, but can occasionally be pink
to lavender. The flowers emerge at the end of a head-like cluster which
potentially can produce 20 or more blooms.
These plants bloom most months of the year, but are killed
by heavy frost and extreme sub-freezing weather. The blooms usually produce
three nutlets covered with wart-like bumps and are the genesis of the next
The nutlets are spread by animals and water flow from heavy
rains. They may be unintentionally scattered by mowing or transported on
equipment to new sites.
Brazil pusley is frequently found in sandy soils which are
common in Franklin and Gulf counties. The plant is a tenacious competitor for
soil nutrients and space on agricultural lands, roadsides and lawns.
The scientific name, Richardia brasiliensis, refers to Richard
Richardson, a wealthy 18th century English physician and botanist. The term brasiliensis
relates to its frequent appearance in Brazil.
Richardson practiced medicine in northern England, but had
studied botany in Holland during his formative years. He had a particular
interest in mosses and lichens, but also vascular plants such as Brazil pusley
and is credited with cataloguing this species.
He corresponded widely with other notable botanists of the
day, and built the largest contemporary collection of plants at his botanical
garden at North Bierley, England. Greenhouses at his estate allowed him to
collect and propagate plants from warmer areas.
Brazil pusley is considered native to the southeastern U.S.,
Central America and northern South America, but has travelled to other
locations. This plant has made appearances in Asia and Africa.
Land managers have been challenged to control this native
with conventional techniques. Post emergent spraying with herbicides provide
minimal to no effect unless the plants are very small.
The most successful technique is the application of a
pre-emergent herbicide to suspected infestations, but this chemical will affect
other seed, too. This method is practical for heavily managed area, but wild
sites will continue to produce this aggressive native plant.
To make matters worse, this species host some destructive
insects. Unfortunately, even modern science has not brought a quick solution to
this native problem specie.
To learn more about this native
landscape pest in Franklin and Gulf counties, contact the nearest UF/IFAS County
Extension Office or visit sfyl.ifas.ufl.edu/find-your-local-office/.
To read more stories by Les Harrison visit Outdoorauthor.com and follow him on