Hypericum fasciculatum (Peelbark St. Johnswort) is an abundant small shrub in seasonal depression marshes in southeastern Florida and beyond. Its root system is centered on a detritus-filled adventitious root cone seated on the marsh floor. From the cone base, shallow horizontal roots radiate across the marsh floor, sending short thin branch roots upward into the overlying water. Additional small aerenchymatous roots climb the outer cone surface to its summit. Also, small roots penetrate the organic cache within the cone. Cones tend to host marshland species in frequencies differing from those on the marsh floor. This report is a natural history observation based on field study describing the root system in detail and in an ecological context.