NORTH ADAMS, Mass. – For those who wish they had more favorite plants in your garden, by propagating new plants from those already there, additional perennials are free.
The easiest method to propagate perennial plants is by rooting cuttings, either in water or in soil. Catmint (Nepeta) and herbs such as oregano (Origanum vulgare) are good choices early in the season or at anytime to overwinter favorite herbs indoors. Using sharp, clean scissors, take cuttings six- to eight-inches long. Put them in water immediately so they don’t dry out while you’re working.
Prepare the cuttings by removing any flowers or buds. Remove lower leaves, leaving only two to four at the top. Trim the bottom on an angle right beneath where a leaf was attached to the stem (called a node).
When dividing daylilies, carefully dig up the plant, saving as much of the root ball as possible, then shake off excess soil, and gently divide the roots into separate plants.
Place each cutting in a container of room-temperature water. Be sure at least one to two nodes are beneath the surface of water, but no leaves are. Place the container in indirect sunlight, changing water weekly. Once multiple roots form and are at least an inch long, pot up using a good quality potting mix.
Some cuttings, such as hydrangea (Hydrangea) root better in soil. Treat the bottom of a prepared cutting with rooting hormone. Using a pencil, make a hole in moist potting mix. Insert the cutting and carefully press soil around it. Water lightly.
Cover the container with a plastic bag to help retain moisture. Vent the cover if excess moisture builds up on the plastic. To check progress, gently tug on the cutting. Resistance will indicate roots are forming.
Hydrangeas, a showy flower found in many Vermont gardens, can be propagated through cuttings, although are best rooted in soil rather than water like many other perennials.
Air layering is a method that works well with woody plants such as forsythia (Forsythia) and lilacs (Syringa). Select a healthy branch at least one-quarter inch in diameter. About a foot from the tip, with a clean knife, cut into the bark below a node at an upward angle.
Remove nearby leaves. Wrap moistened sphagnum moss around the wounded area, and cover with clear plastic. Tightly tie each end closed. When roots have formed, the new plant can be removed and put in soil.
For more information on air layering, see https://go.uvm.edu/layering.
If some perennials are look overcrowded, the time may be right to divide them into two or more smaller plants. Root division works well on clumping plants such as hosta (Hosta), daylilies (Hemerocallis) and ferns (Polypodiophyta). A good shovel, garden fork and a sharp blade will be useful.
Carefully dig up the plant, capturing as much of the root ball as possible. Remove excess soil, and gently divide the roots into separate plants.
If necessary, use a garden fork or clean, sharp blade to divide the roots. Be sure each section contains healthy roots and foliage. Replant divisions as soon as possible to avoid damage to the roots by extended exposure.
Propagation by root division can be the most labor-intensive method of increasing perennial plants. It is best done when the weather is milder, such as early spring or in the fall. Choose a cloudy day to help prevent roots from drying out, and work quickly once the roots are exposed.
Hostas, in particular, are easier to divide in spring when foliage has emerged but not opened. Fall-blooming perennials should be divided in the spring, and spring- and summer-blooming perennials in the fall, at least a month before anticipated ground freezing.
Whatever method chosen, there’s no denying that multiplying perennials is a great way to add plants to a garden.
Deborah J. Benoit is a UVM Extension Master Gardener from North Adams, Massachusetts, who is part of the Bennington County Chapter.
Deborah J. Benoit
