AMES, Iowa ― Part of the fun of gardening is in starting your own plants. Horticulturists with Iowa State University Extension and Outreach discuss plant propagation methods best suited for several common yard and garden plants. To have additional questions answered contact the Iowa State University Hortline at email@example.com or 515-294-3108.
While grapevines can be propagated by several methods, they are most commonly propagated by hardwood cuttings. Hardwood cuttings are made from the dormant canes of the preceding year’s growth. Cutting material should be collected in late winter.
Home gardeners pruning their grapevines in late February or March can make cuttings from the pruned material. Grape cuttings should be approximately pencil-size in thickness and 12 inches long. When making the cuttings, the bottom cut should be just below the lowest bud while the upper cut should be 1 to 2 inches above the top bud.
After making the cuttings, loosely tie them in a bundle. Place the cuttings in a plastic bag with some lightly moistened peat moss, then store in a cool location, such as a refrigerator or garage. As soon as the soil is workable in spring, remove the grape cuttings from cold storage. Set the cuttings in the ground vertically with only the top bud just above the soil surface.
Willows (Salix species) are easily propagated by hardwood cuttings. On a mild winter day in late February or early March (temperatures should be above freezing), go out and collect cutting material. Prune off branches that are about ½ inch in diameter. Bring the branches indoors and cut the branches into 12 to 18 inch sections. Bundle the 12- to 18-inch-long cuttings together with string, twine or rubber bands. Place the bundled cuttings in a plastic bag that contains some lightly moistened peat moss. Place the plastic bag in the refrigerator.
In early April, remove the cuttings from the refrigerator and stick the cuttings into the ground. Place the bottom 6 to 8 inches of the cuttings in the soil. Willow cuttings root quite easily. The cuttings should begin to root and leaf out within a few weeks. An alternate rooting method is to place the cuttings in a container of water indoors. Change the water frequently. When the cuttings have developed good root systems, remove them from the water and plant outdoors.
The forsythia can be propagated from hardwood and softwood cuttings. Hardwood cuttings should be made in late February or early March from the dormant growth of the previous year. Cutting material should be taken from healthy, vigorous stems. After removing the stems, cut them into 6-to 8-inch-long sections. Tie the cuttings in a bundle, put the bundled cuttings in a plastic bag filled with moist peat moss, and then place the cuttings in the refrigerator. In mid-April, remove the cuttings from the refrigerator and stick the cuttings in a pot or flat containing a commercial potting mix. Insert the bottom 2 to 3 inches of the cuttings into the mix. After all the cuttings are inserted, water the potting mix and place the pot or flat outdoors in a partially shaded, protected location. Keep the potting mix moist through the rooting period. The cuttings should root and leaf out in a few weeks. Allow the cuttings to develop good root systems before transplanting them to individual pots.
Softwood cuttings should be made from the current season’s growth in late June or early July. Use a sharp knife to cut off 4 to 6 inch long shoots. Pinch off the leaves on the lower half of the cutting. Dip the base (cut end) of the cuttings in a root-promoting compound. Root the cuttings in a large pot or flat containing coarse sand or perlite. Insert the bottom 2 inches of the cuttings into the rooting medium and firm the material around the base of each cutting. After all the cuttings are inserted, water the medium and let it drain. Cover the container and cuttings with a clear plastic bag or dome to reduce water loss. Then place the cuttings in bright light, but not direct sunlight. Forsythia cuttings should root in 6 to 8 weeks. When the cuttings have well developed root systems, remove them from the rooting medium and transplant into individual pots using a well-drained potting mix.