I begin vegetative propagation of plants in March. Each groundcover, perennial, vine and shrub offers its unique window of opportunity, with some plants providing cutting material for months.
Ornamental shrubs blooming in late spring often have perfect terminal growth for propagation while they are still in bloom.
This week I’m taking cuttings from a rare elderberry, Black Lace. This striking shrub provides vegetative cutting material, April through September.
Plants in bloom may instead have lower side shoots perfect for cutting. Look into the interior of the plant.
Penstemon, butterfly bush and thyme are examples of summer bloomers that may still provide excellent cutting material for vegetative propagation.
English lavender, however, provides cutting material after bloom when new growth begins. The evergreen herbs ‘Bergartten’ sage and rosemary may be propagated all year, although faster rooting takes place March through October.
If possible, choose terminal shoots with leaf nodes close together, whether opposite or alternate. Cut a length of stem that will allow two or more leaf nodes to be in the rooting medium and one or two above. Cuttings should not be too long, especially during warmer weather.
Some cuttings from small rock garden plants will be less than an inch in length.
Other cuttings from vines and ornamental shrubs with greater distance between nodes may be six inches or longer. These will need a tall container, but several long cuttings may be put in the same container.
Work early in the morning, in shade, and take only as many cuttings as you can handle in a few minutes. Cuttings wilt quickly. Do not allow any sun on the cuttings even early in the morning.
You may take cuttings from a plant in the sun in the morning, but once taken, protect the cuttings from more sun during the propagation process.
If the plant is hydrated, watered within 24 hours prior to cutting, rooting is more likely to be successful.
The best medium for propagation of soft-wood (vegetative) cuttings is one-half perlite to one-half vermiculite. The mix should be wet before you begin harvesting and preparing the cuttings.
Carefully remove all leaves along the stem except for the few that will remain above the medium. Determine how many leaves your cutting should have. The larger the leaves, the fewer should remain above the medium. If leaves are large, they may be cut in half to reduce potential wilting.
Reducing the leaf load by cutting a leaf in half during the propagation process will not delay the rooting.
Make your final cut below a leaf node. Dip the dry cutting stem into a rooting hormone (e.g. Rootone), allowing contact with the nodes, and shake off the excess. A cutting should not be wet or it will hold too much of the rooting hormone. Some cuttings root from the nodes, some from the bottom of the stem, where the cut has been made, and some from hairs along the stem.
Work in the shade and keep your propagated material shaded for a few days. Water with a light spray twice a day or more. If larger leaves still show sign of wilting after a few days, cut them in half.
Move the cuttings into bright light but no direct sunlight, and keep them in this exposure for two to three weeks. Shade cloth (30-40 percent) works well for protecting the cuttings in the first few weeks.
After about five to six weeks, your cuttings should be rooted. Some take longer than others. Cut back the elongated terminal bud to stimulate root growth, and pot up the young starts into quart or gallon containers.
Imagine having strong young plants ready for fall planting. It’s possible if you propagate in the next few weeks.
Carolyn has gardened organically in Nevada County since 1977. She will be teaching a propagation class in her garden June 28. Please preregister, 272-4362, or online at www.carolynsingergardens.com. She is the author of the award-winning “The Seasoned Gardener, 5 decades of sustainable and practical garden wisdom”, and two volumes of “Deer in My Garden” (deer-resistant plants), available locally.