The Knack of Cuttings
A lot of plants are finicky about when they like to be cloned.
If only every plant were like coleus — where plopping a sprig in a glass of water guarantees a crop of roots in a couple of weeks or so, and it doesn't matter what time of year you do it.
What you're doing here is selecting the new growth on the plant. Take these at the time when such growth normally appears on the plant you want to reproduce — for woody shrubs, that's usually late spring or early summer. Look for stems that are pliable and green and not hardened, but avoid the tender new shoots. To determine whether the stem is ready for cutting, bend it at a 90-degree angle. If it snaps, it's ready; if it bends without breaking, it's not.
Great candidates for softwood cuttings: lilac, forsythia, euonymus, aucuba, camellia, hydrangea, deutzia, crape myrtle, kerria, rose of Sharon, butterfly bush, photinia, viburnum, spirea, mockorange, sweetshrub, Chinese hibiscus, blueberry, raspberry, elderberry.
How to do it:
- Cut a terminal shoot three to six inches long, cutting a half-inch or so below a node, leaf or bud. If you can, choose a shoot that's not in flower; if in flower, remove the bloom.
- Remove any leaves near the cut end.
- Beginning about one-half to one inch above the cut end, use a razor blade or sharp knife to make a short slanting slice toward the tip; two short slanting slices — on opposite sides of the stem — are even better.
- Dip the cut end in rooting hormone.
- Stick the cutting in a moist, well-draining, sterile rooting medium and firm the soil around the stem.
- Mist the leaves, then cover with plastic to form a mini-greenhouse. Either encasing the entire pot and plant in a clear plastic bag, or placing an upside-down deli container over the cutting will work fine. If you use a bag, put small stakes or straws inside to hold the plastic bag up and away from the foliage.
- Place the plant in bright, indirect light — no direct sun.
- Mist the leaves daily.
- Uncover the plant briefly every day to freshen the air inside.
Here, the wood is fairly hard, and the leaves are full-size. This type of cutting is usually taken between mid- to late summer.
Great candidates: clematis, camellia, daphne, azalea, holly (English, Chinese, Japanese, American, yaupon, Foster), rose, juniper, Leyland cypress, jasmine, Chinese hibiscus.
Take hardwood cuttings in the dormant season, cutting about four to six inches of tip growth. Dip in rooting hormone and stick in potting medium (or directly in soil if it's loose and friable). Mist daily and keep covered in a humidity tent.
Great candidates: juniper, spruce, Chamaecyparis, cedar, hydrangea, rose, spirea, crapemyrtle, hydrangea, heath, heather, broom, wisteria, camellia, abelia, rhododendron, viburnum, yew.
A three- to five-inch cutting usually roots easily, and rooting hormone usually isn't necessary.
Great candidates: many perennials and annuals, including coleus, dahlia, bleeding heart, bellflower, yarrow, dianthus, aster, chrysanthemum and coreopsis.