How to Grow Comptonia Asplenifolia

Choose a sweet fern planting site in full sun in dry, acidic, infertile soil. Sweet fern grows best in soil with good drainage, but does not fare as well in rich, fertile soil.

Plant root cuttings just below the soil's surface, firming the soil over the root pieces gently but firmly. Plant potted transplants by digging a hole slightly larger than the root ball, inserting the root ball into the hole and back filling with the soil removed when digging the planting hole.

Water the newly planted roots or transplant immediately after planting. Monitor the site and water it sparingly once a week for the first month after planting. Thereafter, natural rainfall should be sufficient except during extreme and prolonged drought.

Prune sweet fern after the flowers fade in early summer. Remove dead, diseased or broken branches, as well as any that are crowding others. Cut off any branches detracting from the shrub's overall shape.

Installing an underground barrier around the planting bed contains the roots. In the wild, a single specimen spreads by root suckers into a mass of plants 20 feet or more in diameter. Put a 24-inch piece of galvanized metal or landscaping fabric vertically in the ground at the perimeter of the planting bed containing sweet fern.