Gypsophila paniculata) is a priority invasive species in Michigan’s northern lower peninsula and is a problem invasive in much of the northern US and southern Canada. Baby’s breath readily out-competes native plants in sandy, well-drained soils due to its deep taproot (up to 4 meters), allowing access to scarce resources. Baby’s breath is of particular concern in the dunes because the areas where it is most dense are also populated by several endemic and threatened species. Current removal methods include foliar application of glyphosate and manual removal (severing the taproot). Despite several years of intensive management, high densities of baby’s breath persist in previously treated areas. To determine why this regrowth occurs, our research assesses current removal methods by measuring density and frequency over a large area using a point-intercept grid before and after treatment, determining the regrowth frequency of treated plants, identifying environmental variables associated with high versus low density, understanding the local maturation phenology and investigating how timing of treatment affects regrowth and seed germination.
Results/Conclusions
Our results show a statistically significant decrease in density of baby’s breath after one year of treatment (p < 0.001) but no significant decrease in frequency (p = 0.28). Regrowth of marked plants within one growing season of treatment was seen in 10% (4-22%, 95% CI) of the manually-removed plants and 0% of the herbicide-treated plants. Herbicide treatment was more effective in reducing seed germinability when glyphosate application occurred earlier in the growing season, with germination rates of 0% versus 20% (16–23%, 95% CI) in seeds from plants treated in early versus late July (compared to 97% germination of seeds from untreated plants collected on the same date in late August). Our results confirm that one year of treatment reduces the density of baby’s breath but does not extirpate it, that herbicide treatment does not prevent production of viable seeds unless treatment occurs early in the growing season and that a small percentage of manually-removed plants regrow within the same year. Ultimately, this information will contribute to the creation of an adaptive management plan specific to baby’s breath that can be used in infested areas throughout northern North America.