Comfrey leaves are full of nutrients that make a natural high-potassium fertilizer or addition to compost. This perennial herb sends down deep roots that pull nutrients into the plant's large, hairy leaves. It grows best in moist sites high in organic matter. Common comfrey, Symphytum officinale, is a vigorous plant that can grow up to 4 feet tall. The plant spreads by rhizomes and can become invasive.
More varieties for comfrey
Symphytum x uplandicum 'Variegatum' offers leaves edged in creamy white. In spring it bears lilac-pink bell-shape blooms. It prefers moist soil and part shade. It has the same aggressive growth habit as its plain green cousin, so plant it where it can be contained from spreading. Zones 4-9