Tropical Soda Apple and Spurweed
Les Harrison is the UF/IFAS Wakulla County Extension Director
Though tropical soda apple may sound like an exotic, fizzy drink, it is a conqueror of yards and gardens. Those little melon-like fruits may look cute, but the menacing thorns surrounding them belie the plants true intention.
Spurweed, on the other hand, is exactly what it sounds like–painful.
The Tropical Soda Apple (TSA) poses a significant problem. The vigor of this plant is exceptional, and it will become quickly established in sunny and partially shaded areas, preferring disturbed soils.
As the name suggests, it is native to much warmer climates which rarely experience frost and freezing weather. This perennial pest is capable of springtime regrowth in Wakulla County after multiple frost and freezes.
TSA is in the Solanaceae plant family, which includes tomatoes, potatoes, eggplant, horse-nettles and night shade. Immature plants are often confused with horse-nettles, which display copious quantities of thorns that cause immediate pain on contact.
This exotic pest can easily be identified by its fruit. Developing TSA fruit looks like a tiny watermelon with green and white stripes. Mature fruit turns yellow.
Each fruit contains 200 to 400 seeds, with close to a 75 percent germination rate. Each plant has the potential to produce over 10,000 viable seeds, ready to colonize and infest new ground.
Livestock and wildlife, especially deer and raccoons, are attracted to the TSA’s fruit with its tiny seed. Deer and raccoons have the dexterity to negotiate the thorns, and cattle will nibble on the fruit after it has dropped to the ground or scatted by wildlife.
Undigested seed are conveniently deposited to anywhere the animal roams. The seed are delivered with an immediately available nutrient base of animal manure to encourage growth.
Another pain-inflicting invader is Spurweed, an annual cool season weed which grows very close to the ground. As temperatures warm in the spring, spurweed grows, rapidly forming spine-tipped burrs on its central stems.
It usually grows in open areas such as lawns, fields and pastures through May. The early stage feathery leaves often cause onlookers to confuse this plant with dog fennel, a common native weed, in its spring growth phase.
The burrs are seeds which attach to anyone or anything coming into contact, and are deposited at a new site for germination and vegetative conquest. The technique has been very successful for this plant as it is now established in many temperate and tropical locations worldwide.
Similar to spurweed, and often confused with it, sandspurs are native to Florida. While the plants are quite different in appearance, the painful injury experienced from the seed is identical.
While the habitat preferences and seed relocation methods of spurweed and sandspurs are nearly identical, spurweed are easily encountered this month. The sandspur may be encountered throughout the year.
For more information on tropical soda apples, see the EDIS publication, Tropical Soda Apple: Biology, Ecology, and Management of a Noxious Weed in Florida.
To learn more about exotic invasive plant in Wakulla County, contact your UF/IFAS Wakulla Extension Office at 850-926-3931 or http://blogs.ifas.ufl.edu/wakullaco/