The brilliant yellow of Scrub Hickory and the red of Shining or Winged Sumac. Photo credit: Warren Abrahamson.

Autumn Leaves in Winter Heat: The Changing of the Seasons in Florida

By Dr. Aaron David

We’ve all heard it from our friends up north: “Florida doesn’t have seasons” or “There’s no fall colors”. Nonsense! In fact, winter is Florida’s time of year for peak autumn.

Here in Highlands County, our native Scrub Hickory (Carya floridana) gives us our best color-changing foliage fix. Scrub Hickory is a deciduous shrub that can grow to a short tree and turns a splendid yellowish in December-January before shedding its leaves completely. By February, the branches are completely leafless, but its buds are ready to form new leaves.

Scrub Hickory isn’t the only splash of color we get – stands of Winged Sumac (Rhus copallinum) turn a vibrant red and are found in many disturbed habitats such as along roadsides. Turkey Oak (Quercus laevis) and Red Maple (Acer rubrum) likewise turn nice shades of red, in high elevation scrub and swampy areas, respectively.

These species that display fall colors are examples of deciduous plants that seasonally lose their leaves. Shedding old leaves is a strategy that allows deciduous plants to conserve energy in the colder winter months. Carbon and nitrogen are moved from the leaves to other tissues in the bark or roots and used later to produce new leaves. In some cases, old leaves are diseased and are replaced with healthy ones; each winter, the deciduous Pygmy Fringe Tree (Chionanthus pygmaeus) loses all its leaves, many of which are infected with leaf spot fungi, and puts out new leaves in the spring.

Our natural scrub habitat also has what are known as ‘brevideciduous’ shrubs that shed their leaves and immediately put out new ones. This strategy allows plants to produce new, healthy leaves each year that replace old, potentially diseased leaves while allowing the plant to continue to photosynthesize.

Oaks found in our scrub habitat such as Chapman oak (Quercus chapmanii) and sand live oak (Q. geminata) are brevideciduous and go through this process each winter. Of course, the grand Laurel Oaks and Live Oaks in our yards, parking lots, and public spaces also drop their leaves en masse each winter, creating a thick layer of leaf litter that necessitates that rare Florida weekend chore of raking the leaves. Our red oak species vary a bit more – Turkey Oaks (Q. laevis) are deciduous and lose their leaves for a longer period of time, while Myrtle Oak (Q. myrtifolia), Scrub Oak (Q. inopina), and Bluejack Oak (Q. incana) are considered evergreen and never shed their leaves all at once.

The herbaceous plants similarly feel the changing seasons in Florida. Some endangered herbs such as Highlands Scrub Hypericum (Hypericum cumulicola) die back in the winter and put out new stems in the spring that will flower come summer. Other species like the diminutive Paper Nailwort (Paronychia chartacea) drop their seed and usually die in winter, and the new seedlings germinate in the spring and summer. Others, like the Lake Placid Scrub Balm (Dicerandra frutescens) simply pause or slow their growth, occasionally lose a few stems to the cold, and then continue growing once things warm up.

Of course, Florida winters bring wonderful flowers as well. Winter starts with the yellow flowers of the imperiled Highlands Golden Aster (Chrysopsis highlandsensis) that bloom in scrubby flatwoods habitat. The federally endangered Florida ziziphus (Pseudoziziphus celata) produces clusters of yellow blooms each January. In February, the similarly endangered Scrub Plum (Prunus geniculata) shows off magnificent cherry blossoms throughout yellow sand scrub habitat, and bluish-purple flowers of Skyblue Lupine (Lupinus cumulicola) dot the landscape.

Florida Swamp Privet (Forestiera segregata) produces fragrant, unisexual flowers, with male and female flowers on separate individual plants in swampy natural environments and as an ornamental plant. Several other species produce striking fruits well into the winter, such as the shining black berries of Inkberry (Ilex glabra) and the purple clusters of Beautyberry (Callicarpa americana). Finally, many of the oaks and pines are ramping up their pollen production in the winter, much to the chagrin of allergy sufferers.

While Highlands County has long been known as a place to enjoy “June-in-winter”, the changing of the foliage suggests we actually experience more of an “autumn-in-winter”. And for many of us warm-weather lovers, that’s enough seasonal change for the year.