By Pat Rubin
Sacramento BeeForget for a moment that taking cuttings is a practical and inexpensive way of making more plants.
Forget, too, that science has solved the mystery of how and why a piece of stem can form roots.
So with all practical considerations aside, think of taking cuttings as just plain fun. Science may hold the answers and explanations about why stem cells can produce roots, but it's still a remarkable process.
It's immensely satisfying, after waiting for several weeks, to tip a pot of cuttings over and find amass of white roots gingerly clinging to the side of the stem. And what could be better than to plant those rooted cuttings in the garden and watch them grow and mature, or to give some away to friends? Sharing cuttings makes the garden more personal. My pineapple sage, for example, grows in at least a dozen other gardens, and many of my scented geraniums came as cuttings from friends.
It's also a lesson in patience. You can't rush the process; you can only accept the time constraints and wait.
A cutting produces a plant genetically identical to the mother plant, so it is essentially a clone. Despite the heat, summer months are the best time to take cuttings of most perennials. Be aware that taking cuttings doesn't work for every plant. While many root readily, others need more coaxing, and some are impossible. So grab the pruning shears, the pots and the soil, and head out into the garden to see what you can cut.
The best time to take cuttings is in the morning when plants are freshest, said Bob Hamm, who coordinates several benefit plant sales in Sacramento, Calif. Hamm roots close to 20,000 cuttings a year, mostly perennials such as salvias, geraniums, asters and dianthus, as well as roses, heathers, hydrangeas and more.
Hamm recommends choosing plants that are healthy and strong, and watering them well the day before. Use a sharp knife or shears to take the cuttings. Ideally, you want a cutting 4 to 8 inches long, depending on the plant. I usually cut the branch I'm going to use for my cutting back to where it branches.
I am, in essence, doing some pruning at the same time. You can take only what you need for a cutting, but be careful not to leave any stubby ends of branches sticking out. Cut stems at an angle.
"Avoid the really soft tip growth early in the season, but also don't take the hardened woody growth," Hamm said. "The soft tips you find in spring don't have much structure and tend to collapse. They lose water and dry out. The woody stuff will still root, but it will be much slower."
Take along a bucket of water, and put the cut branches in the water to keep them fresh. If you're taking cuttings of several varieties of geranium, for example, you might want to tie each variety together and label them you can't tell the difference by looking.
You can root the cuttings in 1-gallon pots, 4-inch pots, flats, whatever you have. Hamm recommends filling flats or pots with planting medium and wetting the soil in advance. Some gardeners use straight perlite, while others mix vermiculite and peat with the perlite. Another favorite combination is sand and peat. Sterile commercial potting mixes work well, Hamm says.
Warren Roberts, superintendent of the University of California, Davis, Arboretum, says to avoid mixes that contain manure or fertilizer. "The cuttings are sensitive to the salts in manure, and they don't need to be fertilized, anyway," he says. The soil mix should have excellent drainage, yet not dry out quickly."
Take the stems you've cut and remove the top 4 to 6 inches for your cutting. Make the cut just below a node at an angle. Strip off the leaves from the lower few inches, pull off any large leaves, flowers, buds or sideshoots, and trim remaining leaves back halfway to prevent water loss and to conserve space. Some gardeners dip the cut end in rooting hormone. Hamm uses rooting hormones with hardwood cuttings, but doesn't generally use them when rooting perennials because they root easily.
Cuttings should be spaced an inch or so apart in the pots, Hamm says, though it also depends on the size of the plant and leaves. Tiny lavender cotton (Santolina) cuttings can be squeezed more closely together, while cuttings of pineapple sage (Salvia elegans) need more room.
Using your finger or a pencil, make a hole in the soil, insert the cutting and pack the soil around the cutting. Half to two thirds of the cutting should be in the ground. Water thoroughly. Some people put plastic bags over the pots to simulate a moist greenhouse environment. A greenhouse isn't necessary, Hamm says, but high humidity helps.
Now comes the tricky stage: If you don't pay attention to your cuttings every day, you'll lose them. They need to be out of the direct sun but not in deep shade.
The high shade of a well-leafed tree is good. They need to be kept moist but not soggy, and never allowed to dry out. They need to be gently misted a couple times a day when temperatures creep up into the 90s and especially when the thermometer hits 100.
Then you wait. Salvia cuttings can root in as few as three weeks. Geraniums are usually rooted and growing in six to eight weeks. As long as the stems are green and the leaves are hanging on, there's life and there's hope. Roses may take months, however, and typically drop all of their leaves before they root. Hamm puts his cuttings on an east-facing porch that gets no midday sun.
The roots that form along the stem are called adventitious roots, and they are brittle and easily broken at first.
"Handle cuttings with gentleness and patience and hope," Roberts admonishes. However, I admit to being an impatient and curious gardener and cannot resist tugging on the cuttings to see if they are rooted. If the cuttings resist, I know they are rooted. Another method is to turn the pot over and check for roots growing near the drainage holes.
Once the cuttings are rooted, pot them into bigger pots or into the garden. They will need some coddling and nurturing until they are acclimated to the outside world.
18 plants that grow easily from cuttings:
Aster
Azalea
Boxwood
Camellia
Chrysanthemum
Dianthus
Gardenia
Geraniums (Pelargoniums)
Honeysuckle
Hydrangea
Jade plant
Lavender
Penstemon
Rose
Rosemary
Salvia
Veronica
Willow
)
)