Garden Propagation Tips

Starting your own plants from seeds, cuttings, divisions, and layering saves money and expands options. But be prepared to give propagation a certain amount of attention. Young plants, like young children or young puppies, need tender loving care to get them off to a good start.

Propagating your own plants is actually quite simple to do if you follow these basic tips.
Propagating your own plants
is actually quite simple to do
if you follow some basic tips.

Many plants grow well from seeds, especially annual flowers, herbs, and vegetables. You can find dozens of new, rare, or old-fashioned varieties in seed catalogues that aren't available in the local nurseries. Seed sowing allows you to grow a few, dozens, or even hundreds of seedlings from a seed packet costing a dollar or two. That's economy!

Certain special plants don't grow from seeds. They need to be cloned (vegetatively propagated). This is done by rooting sections of stems or sprouting chunks of roots. Clump-forming plants can be divided into several pieces, and some stems can be rooted while still attached to the mother plant. The tips included in this article will help make the transition from old plant to new as smooth as possible. We'll start by going over basic tips to assist in all types of propagation.

  • Keep a notebook, calendar, or advance planner to remind you when to plant seeds or take cuttings. For example, seeds such as tomatoes and peppers need to be planted six to eight weeks before the last spring frost, but squash and cucumbers need to be planted only three weeks before the last spring frost. It can be hard to remember everything (and squeeze it into your schedule) unless it's written down.

  • Keep good propagation records to track how successful each operation has been and how the young plants are proceeding through the seasons. These records will guide you about when to plant, divide, start seeds, or collect seeds for future years. Jot down your observations weekly in a notebook. Or keep an index card on each plant you propagate so it's easy to find the next time. Some gardeners may want to computerize their records. Here are some things to note:
    • How long seedlings grew indoors before being transplanted outdoors, and whether that timing allowed enough, too little, or too much time for a great performance outdoors.
    • When you planted seedlings outdoors and how well they responded to the weather conditions at that time.
    • When the first shoots of perennial flowers and herbs emerged in spring and were ready to divide.
    • When you took stem cuttings from roses, lilacs, geraniums, impatiens, chrysanthemums, dahlias, and other plants. Rooting success often depends on the season in which the cuttings were taken.
    • When seed pods matured and were ready to harvest for next year's crop.

  • "Harden off" seedlings and cuttings before they go out into the garden. When growing in the protection of a windowsill, light garden, or greenhouse, young plants are tender and can be easily damaged by strong winds or sun. Toughen them up (a process called hardening off) to make the transition from indoors to outdoors successful.
    • Days 1 and 2: Put well-watered young plants outdoors in a shady location for several hours. Bring them back indoors when the time is up.
    • Days 3 and 4: Increase the length of time seedlings stay outdoors in the shade.
    • Days 5 to 7: When well adjusted to shade, gradually move sun-loving plants into brighter light, starting with an hour of sun the first day.
    • Days 8 and beyond: When seedlings can stay out all day without burning or wilting, they are ready for transplanting.

Check out the next section for suggestions on sowing seeds.

Want more gardening tips? Try:

  • Gardening Tips: Learn helpful hints for all of your gardening needs.
  • Annuals: Plant these beauties in your garden.
  • Perennials: Choose great plants that will return year after year.
  • Gardening: Discover how to garden.

Sowing Seeds

Starting plants from seeds is one of the most common -- and economical -- ways to propagate. Check out the dozens of tips in this section to help you sow seeds.

Reuse household items like egg cartons to hold seedlings.
Reuse household items like egg
cartons to hold seedlings.

  • Watch the color of ripening seed pods, which is the clue to when seed is ripe. When dry pods turn from bright green to dull green or brown and succulent fruits turn bright colors, the seeds are mature and ready to harvest.

  • To keep ripening seeds from escaping when a pod dries and splits open, slip a net made from an old nylon stocking over the seed head. Secure it to the stem with a twist tie.

  • Keep dry seeds drier by refrigerating them. This works with both seeds you've collected from dry pods in the garden and leftover packaged seeds. Keeping these seeds in low humidity will encourage a long lifetime. Put collected seeds in dry envelopes. Keep packaged seeds in their original packets as long as they are dry. Enclose them in a sealed plastic bag or glass jar and put them in the refrigerator, where the air is extra arid. Avoid putting them in the humidified produce keepers.

  • When planting, label all seeds with plant and cultivar name and date sown. Because many seedlings look alike, facing an unlabeled flat would be a nightmare. Labels help you remember such things as which little green sprouts are the zinnias and which are the marigolds.

    The cultivar name lets you tell hot peppers from sweet peppers (very important!) and red pansies from blue pansies. Since cultivar names like Hungarian Wax pepper may be too long for short plant labels, come up with code abbreviations (such as "HW pep") and note them in your propagation records for future reference. Write on wooden or plastic tags with permanent ink.

  • Make your own labels out of milk cartons or plastic jugs instead of buying them. Simply wash them out, cut them into strips about 1 inch wide and 4 to 6 inches long, and write right on them with permanent ink or wax pencil.

  • Label like the pros. When planting in a flat, organize plant tags neatly so you can remember which plants they are referring to. If planting the flat with the long side closest to you, run rows of seeds from the front to the back, starting at the left side and ending at the right side. Insert a new label in the planting row each time you start using a different seed. This technique also works for flats of cuttings.

  • Sow perennial and wildflower seeds outdoors in raised beds or spacious nursery pots (the kind you get big flowers in at the nursery) and let nature get them ready to sprout. Hardy perennials and wildflowers often have a special defense called dormancy that keeps them from sprouting prematurely during a temporary midwinter thaw (which would be damaging when the frost returned). They require a certain amount of cold -- or alternating freezing and thawing -- to indicate when winter is truly over and spring has begun. The easiest way to accommodate the cold requirement is by putting them outdoors.

  • Instead of buying pots or cell packs, recycle household containers for starting seedlings. Try some of the following:
    • Egg crates or milk cartons cut lengthwise
    • Clear plastic bakery containers with lids that provide a greenhouse-like atmosphere
    • Yogurt cups
    • Cottage cheese containers
    • Plastic foam coffee cups

Some Perennials that Don't Need Stratification
There's no need for stratification for these plants:
Wash the containers out thoroughly with soapy water, then sterilize them with a solution of 1 part bleach to 10 parts water. Poke holes in the bottom to allow excess water to drain out.

  • Give certain summer blooming perennials a brief cold chill to synchronize their germination. Provide four weeks of cold, moist conditions (a process called stratification) to perennials such as asters, goldenrod, sneezeweed, and blazingstars before encouraging them to grow.
  • To stratify perennial seeds that require a cold treatment to germinate, sow them in a community flat of moist seed-starting mix. Label, then wrap the entire flat in a plastic bag and close with a twist tie. Set the flat in the refrigerator for the time indicated on the seed packet or in a seed-sowing handbook. When the recommended stratification time is up, move the flat into warmth and bright light so the seeds can sprout and grow.

  • If starting seeds in a window, take extra care to maximize light. Use a south-facing window that will receive sun all day. It should not be blocked by a protruding roof overhang or an evergreen tree or shrub. (Without a south-facing window, it's worth considering building a light garden.)

    Hang foil reflectors behind the flat to keep seedlings from leaning toward the sun. If the seedlings are sitting on a windowsill, make a tent of foil behind them, with the shiny side facing the seedlings. This will reflect sunlight and illuminate the dark side of the seedlings. They will grow much sturdier and straighter as a result.

  • Start seeds indoors under lights rather than in a window for even, compact growth. Seedlings must have bright light from the moment they peer up out of the soil. In climates with cloudy weather or homes without south-facing windows, sun may not be reliable enough. A light garden is an ideal solution.

    Set seedlings snugly under a fluorescent shop light. You could place seedlings on a table or counter and suspend the shop light from the ceiling over them. Or you could set up three or four tiered light stands. You can adapt ordinary shelves by attaching lights to the bottoms of the shelves and growing trays below each light. Put the lights on a timer set to turn them on for 14 hours a day and off again (one less job for you). You can't beat the results!

  • Make a mini-greenhouse under lights with a clear plastic garment bag. This traps humidity near seedlings, helping to protect them from wilting. To cover nursery flats full of seedlings, bend two wire coat hangers into arches and prop them in the corners of the flat, one at each end. Work the plastic over the top of the hangers, and tuck the loose ends in below the flat.It's even easier to make a greenhouse cover for individual pots. Slide two sticks (short bamboo stakes work well) into opposite sides of the pot. Then top with the plastic and fold under the pot.
  • Start seeds or cuttings in an old aquarium or clear sweater box to keep humidity high. Aquariums or sweater boxes are more permanent alternatives to the makeshift options above. They are particularly good for cuttings that may need more overhead and rooting room than seedlings.

    To reuse these containers, wash them with soapy water, rinse, and sterilize with a solution of 1 part bleach to 10 parts water.

  • Don't transplant seedlings into a larger pot until they have one or two sets of true leaves. This allows seedlings to develop enough roots to be self-supporting even if a few roots are lost in the process. It's also a time when seedling roots are fairly straight and compact, making them easy to separate from nearby plants.How can you tell when the time is right? It's not as simple as counting the number of leaves on the stem, because the seedling usually has an extra set of leaves called cotyledons or seed leaves. They emerge first and store food that nourishes the sprouting seedlings.When you look closely, you can see that cotyledons are shaped differently from true leaves. Squash seedlings, for instance, have oval squash-seed-shaped cotyledons that are easy to spot. But the true leaves are broad and lobed.
  • To avoid burning seedling stems with the salts on your hands or breaking an irreplaceable stem, handle young seedlings by the cotyledon or seed leaf.

Learn how to propagate by taking stem cuttings on the next page.

Want more gardening tips? Try:

  • Gardening Tips: Learn helpful hints for all of your gardening needs.
  • Annuals: Plant these beauties in your garden.
  • Perennials: Choose great plants that will return year after year.
  • Gardening: Discover how to garden.

Stem Cuttings

Starting a new plant by taking stem cuttings from an existing plant is another common propagation technique. Learn more by checking out the tips that follow.

After stem cuttings survive the winter, transplant them to a larger pot.
After stem cuttings survive the winter,
transplant them to a larger pot.

  • Take softwood stem cuttings in late spring or early summer for fast rooting. New spring shoots are vigorous but soft and succulent. They may wilt before they root. But if the shoots are allowed to mature for a month or two, they firm up slightly and are ideal for rooting.

  • Take stem cuttings in the morning when they are fresh and full of water. Once the stem is severed from its root, it will not be able to soak up moisture for several weeks or until new roots develop. If cuttings are started without enough stored moisture, they will simply wilt and die.

  • Use rooting hormone on older or hard-to-root cuttings. Rooting hormones, available in powdered and liquid forms, contain chemicals (called auxins) that allow cut stems to begin to produce roots. They must be applied as soon as the cutting is taken and before the cutting is put into sterile planting mix.

    Some Plants Suitable for Softwood Stem Cuttings
    Take stem cutting to propagate these plants:
    Not all stems need rooting hormone (mints and willows, for instance), but it can make slow starters much more reliable.

  • Avoid feeding softwood shrub cuttings any additional nitrogen after rooting. A little nitrogen, which is available in nutrient-enriched planting mixes, can help the rooting process proceed. But excess nitrogen can encourage fast, tender new growth that is vulnerable to winter damage.

    Once the cuttings have survived the winter, transplant them into the garden or a larger pot and fertilize them normally.

  • Set a clear glass jar over cuttings of roses, willows, dogwoods, or other easily rooted stems put directly in the garden. The jar will maintain high humidity around the cutting and help prevent wilting. But be sure to protect the jar from the hot sun so the cuttings don't get cooked.

  • Test if a cutting has rooted by gently tugging on the stem. If it shows resistance, roots have formed. After first rooting, allow the roots to develop for several more weeks, if possible, before transplanting.

Sowing seeds and taking stem cuttings are not the only way to propagate. See the next section for other techniques.

Want more gardening tips? Try:

  • Gardening Tips: Learn helpful hints for all of your gardening needs.
  • Annuals: Plant these beauties in your garden.
  • Perennials: Choose great plants that will return year after year.
  • Gardening: Discover how to garden.

Other Propagation Techniques

Some plants can easily be divided at their root clumps, while others require more involved techniques like layering to be successful. Find tips on all sorts of propagation methods below.

Some plants have root clumps that can be easily divided by hand.
Some plants have root clumps that
can be easily divided by hand.

  • Take root cuttings when stem cuttings are not possible. Some perennials, like Oriental poppies and horseradish, have clusters of foliage close to the ground without any stems at all. You can dig up a root and cut it into pieces that may sprout into new plants. With horseradish, you can cut off a side root in the fall and replant it for a new start in the spring. But root cuttings of most other perennials need more help than horseradish. Here's how to do it:
    • Dig the root in early spring before shoots begin to emerge.
    • Cut the roots into pieces an inch or two long.
    • Lay them horizontally in a flat of well-drained propagating mix such as perlite or coarse sand. Cover lightly.
    • Keep slightly moist but not wet (to prevent root rot) and watch for new sprouts to emerge.
    • When the new plants are growing strongly, transplant them into individual containers or put them out in the garden.

  • Easily divide daylilies, hostas, astilbes, or other clump-forming perennials with a sharp shovel. Just slice off an edge of the clump in spring or late summer. Uproot it and replant elsewhere. Keep the new division watered for at least several weeks or until it has regenerated lost roots.

  • Divide a large perennial clump into small divisions to get many little plants fast. This is a quick and easy way to make enough plants for the big drifts, clumps, or ground covers that are so popular in landscaping today.

    A mature bee balm clump might contain 50 rooted sprouts, each of which can be separated off and grown into a new plant. Other easily divided perennials include asters, daylilies, yarrow, phlox, lady's mantle, salvia, coreopsis, hardy geraniums, irises, mint, thyme, oregano, and winter savory. Here's how to make smaller divisions:
    • In spring or late summer, dig up the entire perennial plant clump and wash soil off the roots with a hose.
    • If dividing in late summer, cut back the foliage by half or more.
    • Use your hands to break rooted sprouts into individual pieces. If roots are too hard to work apart by hand, slice them free with a knife or pruning shears. Each section should contain at least one leafy sprout and one healthy root.
    • Replant very small divisions into pots of peat-based planting mix and tend them carefully until they get a little bigger. Larger divisions can go right back into the garden if kept moist until they become reestablished.

  • Root the plantlets on spider plants and strawberry begonias, which grow from the parent plant on arching stems. These pretty plantlets have leaves but no roots, a condition that's easy to correct. Put a pot of peat-based potting mix beside the parent plant and set the plantlet in it. Firm the mix around the lower part of the plantlet and keep it moist. Once the plantlet roots, snip the stem and enjoy.

  • Use layering to propagate hard-to-root shrubs like azaleas. Layering also works well with shrubs that have low-growing or creeping branches, like creeping rosemary. Layered stems develop roots while still connected to the mother plant, which helps nourish the rooting process.
    • In spring, select a low, flexible branch that will bend down to the ground easily.
    • Prepare well-drained but moisture-retentive soil where the stem will touch the ground.
    • Nick the bark off the side of the stem that will touch the ground and remove the leaves near the nick. Dust the cut with rooting hormone.
    • Cover the barren and nicked stem with soil. Top it with a rock or pin it in place with a stake or metal pin.
    • The branch tip will become the new plant. If it is an upright grower, stake the tip upright to give it a good shape.
    • Keep the rooting area moist for several months, until roots develop and become large enough to the support the new plant.
    • Cut the new plant free from the parent branch and transplant it to a pot or new site in the garden.

Propagating plants is a great and economical solution to add even more beauty to your garden. Take heed of the tips outlined here, and you'll have more plants than you ever imagined!

Want more gardening tips? Try:

  • Gardening Tips: Learn helpful hints for all of your gardening needs.
  • Annuals: Plant these beauties in your garden.
  • Perennials: Choose great plants that will return year after year.
  • Gardening: Discover how to garden.