Question: What plants can we take cuttings of now (July) and start rooting them. I do not have a greenhouse but want to learn more on how to start my own plants and maybe sell some plants occasionally. Deb, Danville, Virginia
Answer: Deb, many woody plants can be rooted easily. Although this is usually left to professionals, almost any home gardener can do it successfully. If you have any woody plants in your garden, you probably have some which began their lives as summer-wood slips or cuttings.
Proper timing is probably the most important single factor for success in rooting, especially with many difficult species. There are, unfortunately, no precise or truly scientific means of determining the best time to make cuttings. Even the most skilled propagators rely on such rule-of-thumb methods as color of leaves, color of bark, whether or not stems snap when bent at right angles, and relation of cutting time to time of flowering.
The color of the leaves is said to be particularly useful in timing cuttings of rhododendrons – it is best to wait until the new leaves have turned a dark, lustrous green. Cuttings taken earlier are likely to decay in the cutting bed before they have had time to make roots.
The color of the bark at the base of the current season’s growth is a workable guide in the timing of many species. Short shoots of mockorange, for example, will usually root well when the stems show a few flecks of brown bark near the base.
The Stem Snapping Test
Snapping of stems is probably the best available test for timing cuttings of such varieties as azaleas. It is best to begin testing the young shoots a few weeks after flowering. If the stems break with a sharp snap when bent at right angles, the cuttings are ready for rooting.
Time of flowering is a particularly useful guide in timing cuttings of lilacs. Just before or just after flowering are the most favorable times. Many roses root best just after the petals have fallen.
All of these timing methods are subject to inaccuracies and to various interpretations. Both beginners and professionals could learn a lot by taking small batches of cuttings at frequent intervals during the growing season, and keeping careful records of the results.
Images from InsideUrbanGreen.org
The Mini Greenhouse
Almost any type of enclosure which will retain the rooting medium, protect the cuttings from drafts and admit a moderate amount of light, can be used as a propagating structure. The beginner, who has neither greenhouse, or coldframe, can often get excellent results by inverting a 2 liter soda bottle or small aquariums over cuttings which have been planted in pots and boxes, or even in the open ground.
Except in very shady locations, it will be necessary to reduce the light. It is also desirable to provide a little space at the base of the jar for ventilation, especially during the warmest part of the day. Clay flower pots should be plunged to the rim in well drained soil to prevent drying out; boxes may be placed on the surface of the soil.
Coldframes are among the most useful propagating structures for either commercial or amateur propagators. Frames for summer-wood cuttings should be reasonably well constructed and equipped with tight-fitting glazed sashes spattered with white paint or whitewash. It is desirable to have supplementary coverings, such as slatted lath shades, cheesecloth or coarse burlap. These can be used on top of the sashes to provide additional shade for recently planted cuttings, and as replacements for the sashes after the cuttings have rooted.
Hormones To Supplement
The growth of plants is apparently regulated by naturally occuring chemical substances, which are formed in the buds and leaves. These chemicals, commonly called hormones, are very important to successful rooting, since they are believed to bring about an accumulation of food materials at the basal end of the cutting. This accumulation provides energy for new root development.
Although they are not indispensable, synthetic hormones have been widely used to supplement natural hormones in the rooting process. These synthetic hormones are quite generally available in powder form under various trade names. They are particularly useful in rooting hollies and rhododendrons. When used judiciously, they tend to hasten rooting and to increase the mass of roots. in a wide variety of species.
Hormone powders are usually applied to the basal cut surfaces of the cuttings by some kind of dipping method. One good way is to spread a thin coating of the powder, say 1/16 of an inch thick, on a clean sheet of paper. This can easily be done by using an old salt shaker or spreading the powder with an old table knife. The cuttings should first be moistened by dipping them in about 1/4 inch of clean water.
The best procedure is to pick up the cuttings in bundles of ten or more, hold them loosely and tap them lightly on a flat surface until their basal ends are uniform throughout the bundle, dip them in water, shake off the excess water, and then tap them lightly on the hormone-coated paper. When powder and paper become soggy, prepare a fresh sheet. Never return used powder to the original container. It is much better to discard it, particularly if one wishes to use the same powder container intermittently over a long period.
Rooting Mixtures
Clean coarse sand, sand-peatmoss, and peat-perlite mixtures are the most commonly-used rooting media. If you use sand, pick up sand box sand at the local home improvement store. (Low’s – Home Depot). Do not use sand for the seashore… there is too much salt.
The rooting medium should be from four to six inches deep. depending upon the size of the cuttings and the depth of planting.
Summer-wood cuttings should be planted so that the leaves touch, both in and between the rows. Small-leaved species and varieties should therefore be planted somewhat more closely than large-leaved ones. In general. a spacing of 1 to 1 1/2 inches in the row and of two or three inches between the rows will he quite satisfactory. If the cuttings are five to eight inches long, two or three inches will be a satisfactory planting depth. All cuttings should be clearly labelled, showing variety, name and date of planting.
Cuttings should be thoroughly watered following planting. They should be covered with heavily shaded glass or comparable material. During the first week, the glass cover should only be removed for light sprinklings – during Late morning of the hottest days. A moderately warm, moist atmosphere is best but a hot, moist atmosphere is less damaging than a cooler dry one.
During the second week, ventilate a little during the hottest days and sprinkle lightly two, or even three or four times a day, if necessary. Additional water will help to compensate for moisture loss through ventilation openings. It is desirable to avoid sprinkling in the late afternoon, so that cuttings will always go into the night with dry foliage.
Rooting Speed
Cuttings of privet, forsythia, mock-oranges and some vihurnums should begin to root freely by the end of the third week. The fight and air can then be increased quite rapidly, until, at the end of the fifth or sixth week, the cuttings are protected only by a slatted lath or burlap frame.
With slow-rooting species, such as rhododendrons, one may not reach this point for several months, hut the average run of summer-wood cuttings will root in six to eight weeks if they are going to root at all.
Rooted cuttings may be planted directly in sheltered nursery beds, or in the shade of other plants. If possible, avoid planting on hot days and water heavily. Commercial propagators usually plant rooted cuttings in pots, boxes or plant bands, and place them in shaded co]dframes. In any event, almost any planting operation is a shock to the plant; rooted cuttings require special protection from strong winds and bright sunlight, especially for the first few days following planting.
The only way to learn how to root cuttings is to start rooting them. Be sure to make allowances for failures by trying 10 to 20 cuttings each of several varieties. Teach yourself how to time cuttings by making several batches of the more difficult varieties at intervals of 10 days during the period which is considered most favorable for rooting.
by R Fillmore
