During the Christmas Bird Count, I visited the Port St. Joe Airport and saw a number of interesting plants there. I couldn’t help but notice a very healthy stand of dwarf sundew creating a pretty red carpet around the drainage ditches.
The sundew family, Drosera, has almost 200 species and is found on every continent except Antarctica. It is the largest family of carnivorous plants, most often found in wetlands.
Carnivorous plants use the nitrogen in insect protein to supplement the poor mineral nutrition of the soil in which they grow.
There are five species of sundews in Florida: Dwarf, pink, thread leaf, spoonleaf and Tracy’s sundew. All are found in Franklin County but the dwarf sundew is the commonest by far.
The plant is called sundew because of the gel like glue on the leaves that helps the plant trap insects.
Both the botanical name, from the Greek word “drosos” and the English common name, sundew, roughly translate to mean "dew of the sun" and refer to the glistening drops of glue at the tip of each tentacle.
Sundews are mostly perennial and form rosettes of leave that vary in height from a quarter inch to three feet.
All species of sundew are able to move their tentacles in response to contact with digestible prey. The tentacles are extremely sensitive and will bend toward the center of the leaf to bring the insect into contact with as many stalked glands as possible.
The flowers of sundews are held far above the leaves by a long stem. This separation of the flower from the traps was once thought to be an adaptation meant to avoid trapping potential pollinators but recent research found insects commonly trapped by sundews are different species from their pollinators. Botanists now think the tall flower stalks probably help raise the flowers to a height where they are noticeable to pollinators.
The root systems of most Drosera are often only weakly developed, serving mainly to absorb water and to anchor the plant to the ground. The roots are relatively useless for nutrient uptake.
Many species of sundews are self-fertile; their flowers will often self-pollinate upon closing.
The tiny black seeds germinate in response to moisture and light, some species also require cold.
New plants are also produced in some species when specialized roots called stolons come near the soil surface or where old leaves contact the ground.
Sundews were used as medicinal herbs as early as the 12th century. It has been used commonly in cough preparations in Germany and elsewhere in Europe. Sundew tea was especially recommended by herbalists for dry coughs, bronchitis, whooping cough, asthma and "bronchial cramps". Today, Drosera is usually used to treat ailments such as asthma, coughs, lung infections, and stomach ulcers.
Medicinal preparations are primarily made using the roots, flowers, and fruit-like capsules. Since all native sundews species are protected in many parts of Europe and North America, extracts are usually prepared using cultivated fast-growing sundews.
Cultivation requirements for sundews vary greatly by species. In general, they require high moisture content and full direct sunlight. Water must be very pure and sundews should never be fertilized.
The glue produced by Drosera has remarkable elastic properties and has made this genus an attractive subject in biomaterials research. Because living cells attach readily to the mucilage, research is underway to determine if it can be used by surgeons during organ transplants or hip and knee replacements.
The roots of the tuberous sundews native to Australia are considered a delicacy by the aborigines. In the Scottish Highlands, purple and yellow textile dyes were prepared from sundew roots. A sundew liqueur called rosolio is still produced using sundew roots in Italy using a recipe from the 14th century.