The pitcher plants are putting on a good show for The Nature Conservancy! This Low Mountain Seepage Bog in western North Carolina is home to one of only two North Carolina populations of the green pitcher plant (Sarracenia oreophila). This type of bog is an open, shrub or herb-dominated wetland with acidic soils, often with disjunct populations of species characteristic of the Piedmont and Coastal Plain. This bog sits at the base of a high knob, where groundwater flowing downward reaches a break in slope and seeps to the surface. This groundwater is the primary source of water for the wetland, which like most mountain bogs is technically a fen.
The carnivorous green pitcher plant used to be much more common throughout the Piedmont, but development and draining of wetlands, fire suppression, and other factors have driven the species to near extinction. An important feature of this site that has allowed the species to continue to thrive here is a thick layer of clay soil near the surface. This clay prevents water from soaking quickly back into the ground, and it continues to hold moisture even when the water table drops in summer and fall, giving the plants a sort of water savings account to get them through drier times.
Pitcher plants require full sun for optimal growth and seed germination, and most mountain bogs are experiencing an encroachment of trees and shrubs due to a lack of disturbance. A key reason that this site supports green pitcher plants to this day is because the previous landowner burned it annually from 1908-1972, which prevented these woody plants from taking over. Beyond just creating shade, woody species use a lot of water. Monitoring wells at the site have demonstrated that areas with woody encroachment have a lower water table. This makes life difficult for pitcher plants.
Under TNC management, the site has been burned every 2-3 years since 1992. In addition to burning, TNC manually and chemically controls woody vegetation to prevent encroachment, and the cut stems help provide fuel continuity for burns. A burn was completed this year in late March with the help of the Georgia chapter of TNC and Mountain True. Burning conditions were excellent, and there was enough dry grass in the meadow portion of the preserve that we were able to forego drip torches and just set it off with our lighters.
Thanks, everyone! These happy pitcher plants are the reward for your hard work.