When it comes to propagating the asparagus fern, be careful what you wish for. This clingy vine with the wispy fern-like leaves and strong, spiky stem is considered by many to be an invasive weed. One established, it is difficult to control or to get rid of. Be especially careful when handling this plant as the main stem is covered with sharp thorns, which are technically the primary leaves of the plant. The asparagus fern is most easily propagated through its rhizomes (roots). Asparagus fern grows best in USDA hardiness zones 9 through 11 although it can survive in much of zone 8. This plant does not like frost or freezing weather.
Find a well-established asparagus fern that you wish to divide.
Dig a wide hole around the fern that you wish to divide with a spade. Dig down at least 5 inches all the way around the plant and then carefully shove the spade under the plant and lift. The spider-like roots should lift up.
Keep the roots damp, spraying them with water from a spray bottle.
Use your fingers or pruning shears to divide the root mass into four to six clumps. If roots fall away as you are cutting do not be concerned. Simply keep bunches of roots together. Even broken roots can take root and sprout.
Dig holes to receive the roots that are approximately 3 to 4 inches deep and wider than the roots you are planting. Place the roots into the hole and cover them over with garden soil. No fertilizer is required.
Water well just after planting. Allow the soil to get very wet and then allow it to dry somewhat, although do not let it dry completely. Keep the area moist but not soggy until thin green sprouts begin to poke above the soil. Once the plant begins to grow cut back on watering and water normally. This plant is very drought tolerant.