Many ornamental shrubs in the home landscape may be propagated by softwood cuttings. Softwood cuttings are taken in late May through early July from the current season's growth. Cutting material should be flexible but mature enough to snap when sharply bent. Lilac, forsythia, weigela, barberry, potentilla, and viburnum are some of the shrubs that may be propagated from softwood cuttings.
A proper rooting medium is needed to successfully root softwood cuttings. The rooting medium must not only retain moisture but also drain well and provide physical support. Coarse sand, perlite, and vermiculite are good rooting materials.
The container that holds the rooting medium must have holes in the bottom for drainage. If only a few cuttings are taken, a large clay or plastic pot should be adequate. A wooden or plastic flat may be used if larger quantities are rooted. Once the container has been filled, the medium should be watered and allowed to drain before the cuttings are inserted.
When taking cuttings, remove plant material with a sharp knife. Softwood cuttings should be approximately 4 to 6 inches long. Pinch off the leaves on the lower half of the cutting. Also remove any flowers. Make a fresh cut just below the point where one or two leaves are attached to the stem (node), then dip the base (cut end) of the cutting in a root-promoting compound. Tap off any surplus material.
Whereas cuttings from some shrubs root easily, others are more difficult. Root-promoting substances increase the percentage of cuttings that root, shorten the period needed for rooting, and increase the number of roots per cutting. Root-promoting materials, such as Rootone, are often available in garden centers and mail-order companies. Most products are in powder form.
To avoid brushing off the powder when inserting the cuttings, make holes in the rooting medium with your finger or a pencil. Insert the cuttings approximately 2 inches deep into the rooting medium. After all the cuttings are inserted, carefully water the medium and let it drain.
Water is critical to the survival of the cuttings. A cutting has no root system to absorb water, yet continues to lose water through its leaves. The cutting will wilt and die if it loses a large quantity of water. Water loss can be reduced by placing a glass jar over the cuttings or by inserting several stakes just inside the wall of the container and then placing a clear plastic bag over the cuttings and container.
Once covered, place the cuttings in bright light, but not direct sunlight. Inspect the cuttings daily. Remoisten the rooting medium should it begin to dry. Rooting of most deciduous shrubs should occur in 6 to 8 weeks.
Examine a few cuttings after 4 or 5 weeks. Carefully dig up several cuttings to check on root development. If rooting is poor, place the cuttings back in the medium, water them in, then cover again with a jar or plastic bag. When the cuttings have a well-developed root system, they should be hardened off in preparation for transplanting. Remove the covering but don't allow the cuttings to wilt. Keep the rooting medium moist. After several days, carefully remove the cuttings and transplant them into individual pots with a good potting mix. The young plants can be planted into the ground in a few weeks. Home gardeners may want to grow them in the garden for 1 or 2 years before moving the small shrubs to their permanent site in the landscape.
It takes several years for rooted cuttings to become nice-sized plants. However, many gardeners find rooting cuttings and growing the small shrubs to be fun and rewarding.
This article originally appeared in the May 23, 1997 issue, p. 78.