Asparagus fern (Protasparagus densiflorus) is not a real fern, but an evergreen, perennial member of the lily family. Also referred to as emerald fern and foxtail fern, the plant is a native of South Africa. Asparagus fern is widely used as an ornamental plant for containers and as a groundcover. The plant has however escaped cultivation in many regions and is classified as an invasive weed. Asparagus ferns cannot be propagated with cuttings.
The recommended way to propagate new asparagus plants is with the use of seeds or by dividing the plants, as suggested by online plant resource Floridata. Though cuttings are a very commonly used method of plant propagation, it cannot be applied to the asparagus fern. The University of Missouri Extension also recommends propagating asparagus fern by division.
Propagating by Division
The best time to divide asparagus fern is during spring when the plant is growing actively. Prepare new pots for the new plants. Carefully slide out the plant from the containers. Using a sharp scissors, cut the root ball into multiple sections depending on the size of the plant. Each section should have a good number of roots, leaves and stems. Plant each section in individual pots and water well. Keep plants out of direct sunlight until the plants are established and growing well.
Propagating with Seed
Buy fresh seed from a reliable source and soak overnight in slightly warm water. Sow in a medium sized pot filled with a good potting soil. Do not sow very deep but just below the soil surface. Keep pot at room temperature. Asparagus fern seeds germinate very slowly with a germination time of a month or longer. For planting outdoors, start seeds 14 to 18 months prior to last frost date in the area. (Reference 5)
Asparagus fern grows best in fertile, well-drained soil amended with humus. Plant in areas of full sun to deep shade. Plants tend to start yellowing if exposed to very hot sun. Water enough to keep soil consistently moist. Divide the plants every one to two years to maintain healthy growth. Prior to dividing, cut the stems to a length of about 6 inches to minimize long mingling stems.