In 1757, a survey of the Hillsborough River was done by Don Francisco Maria Celi, pilot of the Spanish Royal Fleet.  He ventured up to the Temple Terrace area in search of longleaf pine to use as masts for his ships.  He named the pine forest of the area "El Pinal de la Cruz de Santa Teresa" or "The Pines of the Cross of Saint Teresa".  There is a plaque commemorating his exploration at Riverhills Park in Temple Terrace.

This illustrated map of the Temple Terrace area was found with the log book of Spanish explorer, Don Francisco Maria Celi, and dates from around 1757.

Late last summer, many using the river noticed numerous mats of plants floating down the river.  This is typically water hyacinths.  Water hyacinths are a free-floating perennial aquatic plants native to tropical and sub-tropical South America. With broad, thick, glossy, ovate leaves, water hyacinth may rise above the surface of the water as much as 1 meter in height. The leaves are 10-20 cm across, and float above the water surface.  They have long, spongy and bulbous stalks.  The feathery, freely hanging roots are purpleblack.  An erect stalk supports a single spike of 8-15 conspicuously attractive flowers, mostly lavender to pink in color with six petals.

One of the fastest growing plants known, water hyacunth reproduces primarily by way of runners or stolons, which eventually form daughter plants.  It also produces large quantities of seeds, and these are viable up to thirty years.  The common water hyacinth (Eichhornia crassipes) are vigorous growers known to double their population in two weeks.  Water hyacinth has been widely introduced throughout North America, Asia, Australia and Africa.  In many areas, it is a pernicious invasive species.  First introduced to North America in 1884, an estimated 50 kilograms per square meter of hyacinth once choked Florida's waterways; although, it is now largely under control.  When not controlled, water hyacinth will cover lakes and ponds entirely.  This dramatically impacts water flow, blocks sunlight from reaching native aquatic plants, and starves the water of oxygen, often killing fish or turtles.  The plants also create a prime habitat for mosquitoes, the classic vectors of disease, and a species of snail known to host a parasitic flatworm which causes schistosomiasis (snail fever).  Water hyacinth is often problematic in man-made ponds if uncontrolled, but can also can provide a food source for gold fish, keep water clean, and help to provide oxygen.

The State of Florida has an invasive aquatic weed control program.  The Florida Department of Environmental Protection contracts with Hillsborough County's Mosquito Control to apply herbicide in public waterways to control water hyacinth and other invasive aquatic weeds.