If you’ve dreamed of sweeping displays of your favorite flowers or carpeting that hard-to-mow hillside with durable ground cover, but get sticker-shock when pricing out the plants, remember that you have other options. With a little time and effort, you can multiply the plants that you already have.
Many hardy plants are easily propagated from cuttings. A large quantity can be propagated at once, and the new plants are easy to care for until they are ready to be installed in a new planting. If you tackle the project now, the only impact on the parent plant is that it will be a little shorter and fuller than normal.
Ground cover plants include trailing stonecrops (Sedum species), dead nettle (Lamium), myrtle (Vinca minor), Japanese spurge (Pachysandra) and bugleweed (Ajuga). Perennials that are easily propagated by cuttings include tall garden phlox (Phlox paniculata), balloon flower (Platycodon), asters (Aster), false sunflower (Helianthus), Chrysanthemum and Helen’s flower (Helenium). If you don’t have plants to propagate from, you may beg some cuttings from friends — offer to demonstrate the benefits of an early season trim.
Begin by gathering some old bedding plant flats. If you don’t have any, ask your gardening friends, as most of us keep a stash of them for these projects. Forty-eight or 36-cell trays with packs of four or six work great for ground covers or perennials, and two or three inch pots may also be used, especially for larger-growing perennials. Rinse with a dilute bleach solution to sanitize them, fill with fresh professional potting mix, and water to settle the soil.
You’ll need sharp bypass pruning shears or scissors, a watering can, and a stick to use for a dibble—something about 1/8-inch in diameter and three to four inches long. A powdered rooting compound from the garden center chemical aisle is helpful but not necessary. Set up a work table in a cool, shady spot.
Bring a bucket of cool water and your cutters to your stock plants, take three to four inches from the tips of plant or its branches, and put them in the bucket. Make clean cuts just above a set of leaves, and do not take flowers or seed heads, as these cuttings may not root well.
For ajuga, just pluck the ‘baby’ plants that form along the runners.
Use the dibble stick to make a hole in the soil each cell, toward the center. For larger packs you may put two holes, evenly spaced, and for pots you may wish to make a triangle of three holes so that multiple cuttings can be used to fill out the pot. Take each cutting and shorten if necessary to get an ideal proportion of half in the soil and half above, and pinch off the lower leaves so that none will be buried. Dip the prepared cuttings in rooting powder if desired, and stick one or two into each of the pre-made holes. Water the packs gently with the watering can as you go.
Set the newly filled flats in a bright location outdoors out of the direct sunlight, and sprinkle daily with the watering can. After about two weeks, check for root formation.
Once plants are lightly rooted, they can be moved gradually to a sunny spot. Avoid full, all-day sun, as it can be hard to keep the soil moist.
When plants are well-rooted and can be removed from the cells without the soil falling away, they can be transplanted into the garden. Start now and your new plants will have plenty of time to establish before season’s end.