Holly ferns are hardy plants that grow in USDA Hardiness Zones 3 to 9. Many varieties of holly ferns exist, some of which can grow as tall as 30 inches. Expect holly ferns to take several years to grow to their full maturity. Their fronds (leaves) are green, textured and glossy all year long. Plant holly ferns in the spring or fall in full to light shade and in well-draining soil.
Prepare the soil, if necessary. If your soil is heavy or consists of a lot of clay, till about 10 inches of soil. Add 2 inches of organic matter such as pine bark, peat moss, compost or poultry grit. Till and mix together to form a light, well-draining soil.
Dig holes for holly ferns that are twice as wide, but just as deep the container. Remove the fern from the container and set it in the hole. If digging up an existing plant, dig the hole just as deep as the rhizome (root ball) and three times as wide. Set the rhizome in the center of the hole and fan out the roots along the bottom.
Fill the holes back in with the well-draining soil and pat it down to remove any air pockets, which if left can cause root rot. Water well.
Cover the ferns with 2 inches of mulch in the spring and fall. This will help retain moisture and keep the rhizomes and roots warm for the winter. Leaves or straw are excellent mulches for holly ferns.
Fertilize holly ferns in the spring using a slow releasing fertilizer labeled 14-14-14. Follow fertilizing instructions on the label because each brand has different release rates.
Water holly ferns only during dry spells, usually after 10 to 14 days without rain.