Expert Guidance from Minnette Marr on Invasives Control

Minnette Marr discusses plant options for karst features

Members of the SMGA Stewardship Committee received expert guidance recently from Minnette Marr, Lady Bird Johnson Wildflower Center botanist and San Marcos resident. Minnette addressed how to limit invasive plants in the 9-acre, Prospect Park portion of lower Purgatory Creek Natural Area and what should be planted to encourage diversity and groundwater conservation.

Minnette Marr, SMGA advisor

Ligustrum lucidum or glossy privet is a major concern and the subject of efforts to reduce its numbers. Work by the SMGA trail crew at the two karst features (limestone openings to the aquifer) in Prospect Park over the past couple of months have included replacing the cloth debris barrier with limestone rocks and thinning the ligustrum, which blocks sunlight from the ground. Minnette suggested false dayflower, cedar sedge, and Texas winter grass as alternatives to cover the barren soil. Milkweed, southwest bristle grass and other forbs, and coreopsis are also good options to consider. Along the walkways where ligustrum and the ever-abundant ashe juniper shades the trail, Marr suggested persimmon, rusty blackhaw, soapberry, spiny hackberry, anacua, and Lindheimer silk tassel as replacements.

Setting long range goals is an important first step towards replacing invasives and over abundant native plants. In addition to setting goals, transects, photo points, or other means will be used to measure success towards achieving those goals. Minnette emphasized that the landscape is always dynamic and a mosaic and that improvements to attract desired species, a diversity of grasses and forbs, and conservation of rainwater are all beneficial goals.

Stewardship Committee members were pleased to note that lower Purgatory was enjoyed by a number of local residents. During 2 hours on a pleasant Sunday afternoon, groups of dog walkers, runners, and even a trio of musicians enjoyed the natural area.

– Lance Jones, SMGA Stewardship Committee Member