Last modified: Friday, May 2, 2008 5:16 PM EDT
Karen Taylor of Atypical Farm in Norton demonstrates propagating plants from the roots during a recent talk at the Attleboro Library. (Staff photo by Mark Stockwell)

Divide and multiply

ATTLEBORO -- There is a plethora of ways to propagate perennials. Just ask Karen Taylor of Atypical Farm in Norton.

Taylor recently gave the Attleboro Garden Club a presentation and demonstration on the many ways to make perennials fruitful and multiply. For the past 25 years she has been propagating her own plants; dividing, starting the seeds and growing the cuttings.

Perennials, such as lavender, are plants that have more than a two-year lifespan. Bi-annuals, such as foxgloves, live two years but set seeds in two years, so you might have more foxgloves. Annuals, such as petunias and impatiens, last a season.

Taking cuttings is the most common method of vegetative propagation. Cuttings can be made from stems, leaves, roots, parts of leaves and thick canes. While gardeners may not want to be full-fledged propagators, it's good to know how to do vegetative propagation because a person might have an heirloom plant from their grandmother that is no longer available, or they might want to share a plant with a friend. "It's just fun and enjoyable to have succession in the garden," Taylor said.

Here is a primer on propagation she gave the Garden Club.

Stem cuttings are usually taken when the plant is actively growing in spring or summer, though it can be done in other months, too. Cuttings usually include a portion of the stem with some leaves, and are usually 3-6 inches long. In general, each cutting should have a minimum of two nodes, but not more than six. A node is where the leaf emerges. Sometimes it is a bumpy or raised area.

To keep humidity high, place a clear plastic bag over the pot and cutting(s). Move to bright light. Do not place in direct sunlight. Rooting time varies by species. Tender plants with water-filled stems tend to root quickly - within a week - while others with tougher stems may take 10-14 days.

When roots are one-inch long, put the cuttings into individual pots.

Russian sage can be propagated through cuttings taken either before it blooms in June, or long after in the fall. Strip the cuttings down, put them in a hormone and plant in small pots to be placed in the window. "By fall, you will have a plant to plant again."

The tip of the stem is usually selected and often gives the fastest result. Taylor used lavender to demonstrate, taking a cutting and stripping all but the very tip, to encourage root development, she said. Removing the leaves sends more energy to the roots.

Plant in a pot using a sterilized mix.

As the name of the method would imply, tip cutting involves taking cuttings from the uppermost part of the plant. "It's the root to shoot equation," Taylor said. The stem should be cut on a diagonal. Use a hormone with fungicide and well-drained rooting mix. Keep evenly moist, but not wet.

While tip cutting is from on high, basal cutting is from down low, taken at the base of a plant where the nodes are close - nodes are where the leaves come out and generally where the roots come from. It's a method to use when tip cuttings are too fragile.

Dutchmen cutting is similar to basal cutting, but a small portion of root is attached and no hormone is necessary, Taylor said. Lamb's ears are one type of plant that is propagated effectively in this way and it's the best method "if you want instant results."

Hostas and daylilies are best multiplied by division. "It's the most common and the easiest type of propagation for the home gardener," where a mature plant is separated into several smaller sections.

The method works well with blue-eyed grass which is a member of the iris family and blooms little blue flowers the whole summer. Dig up the plant, wash the soil from its roots and pull or cut apart sections from the main plants. Most can be replanted in the garden. "Some you might want to pot if they're very small."

Division is also the method to multiplying Sweet Woodruff, which looks, when unearthed, like it has little white stems instead of roots. Separate plant portions with the "stems," plant them where you want them and they will root and create new plants. "And it keeps blooming and blooming."

If growing by seed, they need to be fresh. Siberian irises are among the easiest to germinate. Seeds need a "cold period" for dormancy if you're taking them from existing plants. Columbine, for example, has pods that turn into brown capsules which you can crush slightly, turn upside down and "the seeds will come raining out." Taylor bags them and puts them in the refrigerator and then plants them the following year.

Anemone pulsatilla "Blue Gloeche," which blooms now, "has fantastic seed heads in the summer," she said. The seeds are located below the fluffy tops which can be sown immediately and are an ultimate perennial because it's hearty and lives a long time, Taylor said.