In the U.S., two species of rhododendrons, Catawa (Rhododendron catawbiensis) and Rosebay (R. maximum), are plentiful in the Appalachian Mountain region. Their roots feed in part on the rich humus material in the rocky mountain soils. Over time fallen leaves, twigs, and flower parts decay into additional humus. Humus improves soil aeration and drainage, yet […]