Plant Propagation

Seeds

The most common approach of plant propagation is gathering seeds from plants you currently have in the garden. Some plants like lettuce and celery will only sprout if exposed to sunlight; others, like phlox and allium, just if they are entirely covered.

Many plants will take advantage of being started indoors six to 8 weeks before the last frost. There are a few plants that either do not like being transplanted or are hardy adequate to take a light frost. Those plants are much better off being planted directly outdoors. A few examples: peas, carrots, corn, beans, nasturtiums, early morning splendor, cucumbers.

Many perennials will greatly take advantage of being sown directly outdoors at the end of summer. That will offer the plants the possibility to experience their natural cold cycle and make them emerge stronger and in their own time in spring.

Difficult seeds like nasturtiums, morning-glory and four o'clocks will sprout easier if taken in warm water for 12 hours prior to planting.

When: Plant annuals in spring, perennials and biennials at the end of summertime, when the heat died down a bit.

Department

A prolific way to increase your garden stock is the department of mature plants Most herbaceous perennials really need dividing in order to stay healthy and blooming. Among those, a few examples: heuchera, daylilies, pampas grasses.

Other plants, like daisies and bee balms will rapidly spread out if delegated their own accord. Dividing them is a good way to control their development and fill bare spots in your garden.

To divide the plant you can either dig it out completely and break the root ball into smaller parts or dig out a part of the clump with a shovel. If you can do that, the benefit is that the staying plant roots will stay undisturbed.

When: Divide spring flowering plants in the fall and fall blooming plants in spring.

Rhizomatous plants.

Among these: bearded irises, peonies, lily-of-the-valley, mint.

For small rhizomes, simply pull out of the dirt and replant somewhere else. For larger roots, dig the plant out at the end of summertime after it completed flowering and cut up the root in 2-4 inch areas with leaf development at one end.

When: End of summer or fall, after they have completed their vegetative cycle.

Layering

This works great with ground covers, strawberries, raspberries, and spider plant. Take a runner and tie it down to the ground with a pin. After the plant establishes roots you can cut it loose from the mom plant and move it someplace else.

When: whenever they choose to grow runners.

Cuttings

Most woody plants can be propagated like that, specifically roses, for whom this is the basic approach of proliferation. Other plants to be propagated by cuttings: butterfly bush, weigela, pelargonium, fuchsia, delphinium, forsythia, chrysanthemums, hydrangeas, African violets.

There are 4 standard kinds of cuttings: pointer cuttings (soft, green), stem cuttings (woody), leaf cuttings (leaf and petiole) and root cuttings.

For stem and idea cuttings, a minimum 3 inch length will ensure the practicality of the plant. Wounding the cutting (making a longitudinal cut or crushing the bottom) will promote the plant to grow new roots.

Many plants, like mint, will grow roots if put in water. Other plants, like African violets and hydrangeas, will enjoy to root if you stick a leaf with a long petiole in the dirt. For plants with big leaves, like hydrangea, it helps to cut up about half of the leaf to reduce the pressure on the establishing root system to feed it.

If you have rooting hormone, I strongly suggest it.

When: For fall flowering perennials and annuals, start cuttings when the risk of frost has actually passed in spring. For spring blooming perennials, start the cuttings in the fall and secure them under cloches (a glass jar would work just fine) over winter season. It is really useful to the plant to go through a winter season in its natural environments, it produces a much healthier root system. This is specifically true for roses.

Bulbs, corms and tubers

Some bulbs, like lilies, will start expanding in a scaly pattern. Each scale with roots can be separated and start a new plant.

Onions can be vertically sliced and divided. For hyacinths there is a method called scooping: cut up the roots off a bulb and dig the main part right below them to expose the bulb layers. Place the bulb upside down half buried in a tray loaded with damp sand. Place the tray in a dark warm place. In 12-14 weeks bulblets will start forming on the top of the large bulb. Plant the bulb upside down with the bulblets right listed below the surface area. Let the plant go through its vegetative cycle. The bulbs can be raised and separated in the fall.

When dividing roots, ensure to have at least one practical "eye" on each area.

When: In the fall, after the plants went dormant.

Dropping and stooling

Dropping consists of lowering and covering most of the plant stems with compost or good quality dirt, and wait for the plant stems to develop specific roots. The plants can be separated and replanted. This works for heathers and rhododendrons.

For the stooling technique mound up dirt high around the bottom of the plant, to give the stems an opportunity to grow roots. A couple of examples of plants for which this approach works: lilacs, willows and dogwoods.

When: Drop and stool in spring, divide and cut in the fall.

Please remember that some plants will successfully propagate through several of these methods.

Here are some excellent resources for finding out more about plant propagation:

American Horticultural Society Plant Propagation: The Fully Illustrated Plant-by-Plant Manual of Practical Techniques - Alan Toogood

Propagation Basics: Tools Strategies Timing - Steven Bradley

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