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AVANT-GARDENING

by Bill

DeBoer

If you love your plants, and want more of them, cut them. Vegetative propagation is a true feat of science that is often overlooked by many gardeners today.Whether it is a lack of confidence or information, cutting a plant should not be reserved solely for pruning. Imagine taking a single plant and reproducing it dozens of times within a couple of weeks. Make this a reality by following a few basic steps to maximize your existing garden. What is a softwood cutting? This is simply a portion of a plant that is not lignified (does not contain wood). Herbaceous annuals and perennials as well as new growth from woody shrubs and trees are considered softwood. These cuttings bend easily and are often green in color.When selecting a softwood cutting, make sure the cut portion is at least three to six inches long. Less than three inches and your rooting potential might be poor (however, there are exceptions). More than six inches and the cutting will have difficultly maintaining turgor pressure and will be prone to wilting. Each cutting should have at least three nodes (although you can sometimes get by with two). Sever the cutting from the parent plant approximately ½ inch above a node. This will cause de-regulation of a hormone that prevents the lateral buds from branching out. Now that the section of the branch has been removed, time is of the 122

Maximum Yield USA | May 2012


essence. High temperatures and low humidity will cause water to transpire out of the leaves and result in wilting. Concentration gradients dictate chemicals, such as water, will move from areas of high concentration to lower concentrations in an effort to reach equilibrium. Therefore, a cutting will lose water via the leaves if the relative humidity on the air is low. You can combat this by increasing the relative humidity of the air. To do this, simply place your cuttings in a baggie, mist with water and seal. If you are outside and will not be able to stick the cuttings soon, place the sealed bags in a cooler (with ice) if the temperatures are warm (60°F and above). If your cuttings have wilted, try using a hydrating solution that florists use on cut flowers. With the cuttings properly moistened, it is time to stick the cuttings. Most herbaceous softwood cuttings will not require auxin treatments (rooting hormone); however some woody softwood cuttings will root very slowly or not at all without proper concentrations of exogenous auxin. If rooting hormones are required, make an additional cut at a 45 degree angle at the cut end.This will increase the wounded surface area ensuring proper absorption of auxin. Whether you use rooting hormone that is carried by talc powder, gel or solvents, make sure you only cover the bottom inch of the cut end. Application too far up the cutting can facilitate rotting. Now simply place the cutting into a suitable rooting substrate.This substrate should hold enough moisture without being waterlogged and be well-draining. Extremes of too much or too little moisture will result in loss of the cutting.

Lastly, make sure you are providing the proper humidity to promote rooting and not rotting or wilting. Some plants such as mums can rot if covered with a dome top or plastic baggie, and will greatly benefit from not being covered at all. When in doubt always cover softwood cuttings to maintain high humidity. If the cuttings tend to wilt quickly, remove all but three or four of the top leaves to decrease transpirational losses. Hopefully this quick guide to rooting softwood cuttings has peaked your interest to make the cut. It truly can be an exciting and easy way to quickly multiply your favorite plant. Make sure you always do background information on the plant you wish to vegetatively propagate. Softwood cuttings might not root optimal relative to semi-hardwood or hardwood cuttings. So what are you waiting for…just stick it! MY

About the Author: Bill DeBoer is a research scientist at Indianabased steadyGROWpro. A master gardener intern, Bill is responsible for overseeing the company’s laboratory operation, including the design and execution of research projects, plant propagation, seed germination and overall plant care. Bill has a B.S. and M.S. from Purdue University, and was previously a research technician for the U.S. Department of Agriculture.

Maximum Yield USA | May 2012

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Making the cut