Weeds of Wednesday: A Tale of 3 Solanums

Invasive exotic pest plants plague natural areas, ornamental landscapes, agricultural operations, and pastures.  Pictured above is tropical soda apple (Solanum viarum), which we saw when we visited Treasure Hammock Ranch on 3-3-2019.  This heavily armed & sun-loving weed of pastures and sod farms, fortunately, is not found at the Oslo Riverfront Conservation Area (ORCA).  It is listed as a Category #1 invader by the Florida Exotic Pest Plant Council (FLEPPC).

At Treasure Hammock, it kept at bay by regular mowing and rare herbicide treatments.  Populations of the tropical soda apple beetle (Gratiana boliviana), a biological control agent, have been established in Florida and may help some.

Turkeyberry (Solanum torvum) is another thorny invasive plant in the genus Solanum that was present at Treasure Hammock and that is not at ORCA.  Mike Sexton, who graciously led our group, shared that this plant is not nearly as problematic as tropical soda apple, as its listing as a Category #2 plant by the FLEPPC suggests.  Like tropical soda apple, turkeyberry has thorns, but it prefers shady areas like hammock edges rather than pastures.

Most of the mature plants at Treasure Hammock were a few feet tall with a sprawling habit and lots of flowers.

Compare the flowers of turkeyberry, the Category #2 invasive Solanum that we saw at Treasure Hammock, and the Category #2 twoleaf solanum (Solanum diphyllum) that grows at ORCA and Treasure Hammock.

This plant was the only one of the three Solanums that was in fruit at Treasure Hammock,  It fruits, copiously, throughout the year.

It has distinctive arrangement of leaves – paired leaves of two different sizes/shapes.

At Treasure Hammock it was growing against the fence of a historic cow pen.

All of these plants belong to the family Solanaceae, the nightshade family, which includes more than 2,700 species in 98 genera.  Many of the plants in this family are of significant economic importance:  Tomato, eggplant, tobacco, potato, green pepper & chili pepper, but others are invasive like this trio of Solanums.

Click here for a comprehensive review of invasive Solanums found in Florida.