Regional Gardening Reports :: National Gardening Association

In the Garden:
Coastal and Tropical South
September, 2009
Regional Report

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All three -- Celebrity tomatoes, Long Red Cayenne pepper, and 'tater vine -- grew from cuttings I rooted.

Passion for Propagation

I've decided to come clean. I think propagating plants is more fun than growing them the first time. If that makes me a weird, plant nerd sort of person, so be it. Fifty years have passed since the third grade girl broke a piece off the begonia and put it in a coffee cup of water. It rooted, and here's some of what I've learned since.

Plant Multiplication
For many gardeners, propagation is a means of having more plants than the budget allows. One robust spirea can be split with an axe after two good years of growth to soon fill twice the space in a border. Sounds gruesome, but such strong measures work well for spirea and other thickety shrubs like abelia. A long rank of attractive pots across the porch or lanai may be in too much shade for all but ferns and cast iron plants. Both can be divided almost annually as they overfill their space and you have more.

But simple multiplication is most easily accomplished by taking cuttings and rooting them. Green, or herbaceous, stems such as philodendron or coleus root readily in water and transplant readily to the soil environment. Four- to 6-inch tip cuttings taken from the healthiest growing points of such plants root readily. Angel trumpet and confederate rose also root well in water, but their cuttings are usually 2 feet long, taken just before a frost or cold snap.

Many other plants, however, develop very fine adventitious roots in water. Such roots can be suffer transplant shock if moved directly from the water to garden soil. Pot up roses and other shrubs that you root in water and allow them to grow on for at least several weeks before moving out to the garden.

Three Woods for Cuttings
Traditionally, wood on growing shrubs is described as soft, semi-hard, and hard wood. Some plants root best from each category, and fortunately, many correlate with pruning. For example, fig trees root from dormant tip cuttings of the sort you'd prune off in winter to control its height.

Crape myrtle, though often pruned in January, roots best from the semi-hard wood of June and July. The new growth on a slender stem will bend, but not as easily as it did when it was new (or soft) and does not snap as it will later in the summer. The principle still applies in that one can prune crape myrtles during the growing season to thin out overgrowth clusters of stems and those will root.

Whenever possible, take woody cuttings 4 to 6 inches long, strip the leaves from the lower half of the stem, and stick 2 inches into a loose potting mix that has been watered once. About 1 inch of bare stem should rise above the mix for good air circulation. The entire task here is to keep the mix moist enough to allow roots to arise, but not so wet that the stem rots.

Sharp Knife
Whatever you use to cut plant material, keep it sharp. Remember you are cutting into living material with the knowledge that it can and hope that it will develop roots where it was cut. Your job is to encourage the natural process, not mangle the cell structure with a dull edge. I use a pocket knife or shears, and always cut on a slant to expose the maximum amount of stem.

Put little pots with cuttings in them into large zip bags if humidity is low. Close the top nearly entirely and let the humidity build up before venting. Glass jars work for this if the fit over the plant and sit on the soil inside the pot's edge, and so do the plastic boxes with clear tops made for roasted chicken at the takeout deli.

Propagation is an almost daily joy, and brings its own rhythm to the year as you take advantage of plants' natural ability to reproduce from vegetative parts. Give them the opportunity, and you'll have plenty to plant and share.

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