Garden Q&A: Winterberry cuttings beat seeds
Q: Is it possible to get a winterberry to grow from seed? If so, how do I do it? If not, is there a different way to make more of them?
A: Winterberry ( Ilex verticillata) is a moderate-sized deciduous shrub that is native to North America. Many species of birds enjoy the bright red berries, and it's a great plant for water-logged soils; plus, it has very few insect or disease troubles.
Winterberries grow anywhere from 3 to 15 feet in height, depending on the variety, and most have beautiful red berries, though there are several cultivated varieties with yellow and orange berries. As with all species of holly, to get berries you'll need to plant one male specimen for every five or six females (males do not develop berries, but the pollen is necessary for fruit production on females).
It is possible to grow winterberries from seed, and, when growing in an undisturbed area, they will do this naturally. When the berries drop to the ground, they ferment and the seeds readily germinate. Various birds use the berries for food as well, dispersing the seeds as they go. You'll have to be a patient gardener, though, to grow winterberries from seed, as it will take many years for them to mature enough to bear fruits and even then, what if you end up with all male specimens? Plus, they have very hard seed coats and require a lengthy period of moist, cold conditions to break dormancy.
You'll have much better luck growing winterberries from stem or root cuttings. Plus, the plants will reach maturity and bear fruit far more quickly than growing from seed. And, as vegetative propagation by cuttings results in an exact clone of the mother plant, you'll know precisely whether the resulting plants are male or female.
Softwood stem cuttings are taken in late spring through mid-summer. Use a clean, sharp pruning shear to remove several 2- to 3-inch-long stem tips. Remove all but the uppermost pair of leaves, dip the lowest inch of each stem cutting into rooting hormone (available at your local garden center), and insert the cut end into a clean pot of new potting soil. After watering them in, cover the cutting, pot and all, with a plastic baggie to maintain high humidity until roots are formed. Water the cuttings when necessary, and tuck the pots under a shrub to keep them shaded. The baggie can come off in a month. They should be rooted and ready to plant that fall.
Alternatively, root cuttings can be taken in late fall/early winter by carefully digging up pencil-thick roots from a mother plant and cutting them off. Each root piece should be 2 inches long. Put each root cutting in its own pot of fresh potting soil, being sure to maintain its polarity (up-end-up and down-end-down). The pots can be sunk into the garden up to their rim and then mulched with a few inches of straw for the winter. Come spring, remove the mulch, pull out the pots and wait for the root cuttings to sprout.
Horticulturist Jessica Walliser co-hosts “The Organic Gardeners” at 7 a.m. Sundays on KDKA Radio. She is the author of several gardening books, including “Grow Organic” and “Good Bug, Bad Bug.” Her website is www.jessicawalliser.com.
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