By John Pohly, Colorado State University Cooperative Extension agent, horticulture
Homeowners can avoid some of the expense of purchasing trees and shrubs if they invest the time to propagate their own.
Plants such as forsythia or golden bells are easy to start from hard wood cuttings during the winter or early spring. Hard wood cuttings are made from branches of deciduous plants (plants that lose their leaves in winter).
You'll need a container of potting soil, a polyethylene bag, some rooting hormone, pruning sheers or a sharp knife and the plant from which you will take cuttings.
Any good potting soil will root the cuttings. Some gardeners root house plant cuttings in water, but a lot of trees and shrubs will rot with this technique. Use a container with drainage holes to hold the potting soil. A rooting hormone usually helps. Almost any garden supply department carries the major brands.
Take a cutting about 6 inches long from the branch and dip its base in the rooting hormone. Shake off the excess hormone and push the cutting base about 2 inches into the moist soil.
Cut some slits in a polyethylene bag that's large enough to cover the cuttings. (The slits will keep the cuttings from molding.) Place the bag over the cuttings to keep them from drying. Place the container in an area where it receives light but not direct sun. Check the soil moisture every few weeks; check, also, to see if the cuttings are rooting.
Among the easy-to-root plants are willows, poplars, privet, rose, red twig dogwood, English ivy, forsythia, arborvitae and creeping juniper.
You can use seeds to start several species of trees and shrubs. Most tree and shrub seeds require a cool, moist treatment (stratification) before they will germinate.
Collect seeds and place them in a sealable sandwich bag with about a cup of moist (not soggy) sand or potting soil. Place the bag in the refrigerator for three months. This creates a false winter environment, which will allow the seed to germinate.
After removing the seed from the refrigerator, plant in a pot of moist soil and place in a sunny location. Most tree and shrub seeds take several weeks to germinate, so don't give up if you don't see little plants in a few days.
Some tree seeds don't require stratification. These include bristlecone pine, ponderosa pine, mugo pine and catalpa. When in doubt, however, stratify the seeds of trees and shrubs.
Photograph courtesy of Judy Sedbrook.
© CSU/Denver County Extension Master Gardener 2010
888 E. Iliff Avenue, Denver, CO 80210
Date last revised: 01/05/2010