Many ways to propagate new plants

PERENNIAL FLOWers should be sonamed not only because the plants live for year after year, but also because the plants can be puttered with almost any time of year. Here it is, almost midsummer, with globe thistles, veronica, tiger lilies, daylilies, and other perennials in their full glory; nonetheless, the time is auspicious to propagate new plants.

Seed is an obvious, but not necessarily the easiest, way to make new plants. Most perennial seeds can be sown anytime from now through the early part of August. Sow seeds either in a seed flat or in a part of the garden set aside as a nursery area. The seedlings can be nurtured at either location until they are large enough to transplant to their permanent homes.

The advantage of the seed flat is that you can give your plants very close attention with respect to watering and fertilization. A flat even can be moved about to give tender seedlings more or less sunlight or breezes, as needed.

Plants in flats can’t be neglected for long, though. Even a day or two without water can spell death for such plants. Seedlings growing in an inground nursery bed have the advantage of greater independence than their counterparts in seedling flats.

Generally, seed propagation will not reproduce “garden forms,” or “varieties” of perennial flowers. Only species forms of seed-grown perennials, identifiable by their lack of varietal names, generally give plants similar to their parents. Examples include yellow flag iris, woodland phlox, and small Solomon’s seal. Plants grown from seeds of the “Cambridge Scarlet” variety of bee balm or the “Robin” variety of cottage pink will not have the same red flowers as their parents. There are exceptions, though. “Sunburst” coreopsis, for example, does come true from seed.

Stem cuttings, taken now, are another way to propagate perennials. Especially easy to root in this manner are rock cress, snow-in-summer, and any sedum. Penstemon and the previously mentioned woodland phlox also are candidates for this method of propagation.

Perennials that can’t be propagated by stem cuttings are those such as Oriental poppy, coral bells, and primroses, all of which grow as rosettes of leaves pressed against the ground instead of stems. Take a stem cutting of a perennial that can be propagated this way by snipping off stems (preferably non-flowering) each at least three nodes long. Strip the leaves from each stem’s lower half and stick the leafless portion into a premoistened mixture of equal parts peat and perlite (sand or vermiculite can be substituted for perlite) in a flower pot.

Cover the pot with a plastic bag, held off the plants with some twigs also stuck in the potting mix. The cuttings will need enough light to manufacture food, but not so much as to turn the miniature greenhouse into a miniature oven. A good location is in the bright, indirect light near the north wall of a building.

Propagation by root cuttings is even easier than propagation by stem cuttings. The only perennials that can be propagated this way at this time are those that go dormant in summer, such as Oriental poppy and bleeding heart. Dig under a plant to extract some pencil-thick roots from the soil. Chop the roots into three inch pieces, then set those pieces horizontally, a couple of inches deep, in either a flower pot or a nursery bed. Be patient and label the pot or bed, for leaves may not appear for awhile. Root cuttings are such an easy method of propagation because there are no leaves to dry out the plants before roots have begun to grow.

Planting bulbils, another very easy method of propa- gation, is unfortunately very limited in application because the only common plants that form bulbils are lilies. Bulbils are those pea-sized, shiny black bulbs that form in lilies’ leaf axils. Flick the bulbils out of the leaf axils and plant them immediately. New lily plants that always pop up at the base of my established plants are testimony to the ease of this method of propagation.

Plants resulting from any of these methods of propagation — seed, stem cuttings, root cuttings, or bulbils — still will be just toddlers at the end of this season. Don’t expect them to go into the winter without an overcoat. To stave off the bitterest portion of winter cold and to keep plants from heaving up and out of the soil, cover them with some type of fluffy mulch like straw, evergreen boughs, or beech or oak leaves. Apply the mulch about the middle of December, as soon as the top inch of soil has frozen. Plants in pots can be planted out in their permanent locations, or kept in their pots, plunged up to their rims in the ground, before receiving their winter garb.

Any gardening questions? Email them to me at garden@ leereich.com and I’ll try answering them directly or in this column. Come visit my garden at leereich.com/blog.