Propagating Plants

The vast majority of plants can be grown from seed, and starting your own seeds, or buying commercially grown seedlings, are often the best ways to begin when you are growing annuals. However, several other methods of propagating plants provide faster and better ways of increasing your supply of perennials, bulbs, and sometimes even shrubs. Modern nurseries sometimes use high-tech tissue-culture methods to propagate plants, in which a cluster of cells is nurtured into a plant grown in a test tube. This has become an inexpensive way to produce disease-free, identical plant cultivars, but it can only be done in a laboratory setting. At home you can use more time-tested methods, such as dividing or rooting cuttings to increase your supply of plants.

Plants that naturally reproduce, expanding into thick clumps are prime candidates to propagate by digging and dividing. Indeed, some plants grow with such vigor that they must be divided every few years
to keep them from becoming so crowded that they fail to bloom well. Early spring, when plants are emerging from dormancy, is usually the best time to dig and divide them, although spring-flowering bulbs are best dug in early fall, and iris are best propagated in late summer.

Digging and Dividing

Before you dig up crowded plants, prepare a bed so that you can replant the best divisions right away. Also water the old planting if needed, preferably the day before you dig, because digging is always easier, and fewer roots are broken, when you dig in soil that is slightly moist.

Use a digging fork to loosen the soil on the outside of the clump, gradually working to the center of the clump. As you encounter the root mass, try to get the fork beneath it, lifting it intact if you can. This is easily accomplished with a crowded clump of spring-flowering bulbs or plants with shallow roots, such as bee balm or lamb's ears. But because the roots are so heavy, it may not be practical to actually lift a huge clump of daylilies or hostas onto a tar p where you can meticulously divide the crowns. Instead, use a sharp spade to cut straight down

through the root mass, cutting it into halves or fourths. Then lift the smaller chunks, and discard severely damaged roots and the crowns attached to them. Pry apart smaller dumps by inserting two garden forks, back to back, and levering the roots apart. You should still have plenty of healthy small clumps that you can divide for replanting.

Rooting Cuttings

Both luck and skill are required to coax 4 in (10 cm) softwood cuttings to root. Take them from healthy stem tips in early to midsummer and insert them into a pot of damp rooting medium, which is usually sterile, soilless commercial potting medium, or a mixture of clean sand and peat moss. Numerous plants are willing to be propagated this way, including dusty miller, artemisia, Russian sage, and even some shrubs including buddleia and bluebeard.

To reduce wilting, pinch off all but the top tuft of two or four leaves from each cutting. Then dip the cut ends into water and then into commercial rooting powder, which is available at garden centers, before tucking them into a pot filled with damp rooting medium. To maintain a high level of humidity, enclose each container in a roomy plastic bag. When kept in a warm, shady place, with close monitoring to ensure that the soil never dries out, at least half of the cuttings should root in 4 to 6 weeks. Some can even be rooted in a jar of water on a sunny windowsill. At the first sign of new growth, gendy transplant the cuttings to containers of fresh potting soil, and pamper them in pots for another month or two before planting them in the garden.