Herbs All Winter

Friday, September 14, 2012
Autumn Cuttings for Cloning The two kinds of stems, green and woody, grow similarly but mature differently. Their condition and growth stage makes a big difference in how they respond to our efforts to clone them. As green stems age, they grow thicker and may develop a ‘skin’ that was not apparent as young plants. While woody stems also thicken, their outer walls stiffen greatly as the interior parts further define themselves. Generally, green stems are solid masses of dense cells at every stage but woody stems look quite distinct in cross section. Their youngest, new growth will be green, semi hard wood has green inside with a thin woody wrapper, which thickens around hard wood and causes it to snap easily. Hard wood cuttings are the subject of a blog for later in the year but the time for both new green stems and semi hard (or almost hard, depending on where you live and garden) wood cuttings is now. At this point in the year, the answers to 2 questions puzzle gardeners in all but the warmest winter realms. Which plants are too tender to survive outdoors where I live? Will they survive indoors if I can find room for them without selling the living room furniture? I say, when in doubt, propagate and solve both these puzzles at once. If you grow tropical plants outside the tropics as so many of us do, their size can add another challenge also solved by propagation. Tropicals like Dieffenbachia and Schefflera can go from indoors to the porch outside annually for years without much trouble. Others, including vines like Mandevilla, can drop every leaf from a mature specimen upon entry to the indoor garden. Young sprouts, freshly rooted in fall, take to indoor garden conditions much more readily. Heat and dehydration are the enemies of cuttings taken in fall. A smart strategy is to set up the pots or rooting bed first and then carry a container of water to the garden along with your cutting knife. Slice the stem longer than you want it to be, remove flowers and leaves on the lower half, and plunge it into the water quickly. Add a few drops of Hormex Liquid Concentrate to the water, especially if you cannot get the cuttings into the media right away. If you must transport the cuttings, make them twice as long as you ultimately want them to be, put into a plastic bag, and refrigerate. It is important to keep these water vessels and plastic bags out of the sun or all that will be left is slimy, useless plant material. Take my word for it and avoid the yuck factor by preparing the rooting space first. Bring in the cuttings, shorten their length if needed, and make a fresh cut on a slant. Soak each cutting in HLC for 10 minutes or roll its tip in the appropriate Hormex Rooting Powder. Stick several into each pot or plant flats more closely together than in spring or summer. If cuttings are particularly leafy, grab scissors and snip off half of each leaf – not half the leaves, but the outer half of each one. This reduces water loss through the leaves and saves room in the rooting bed. Whether you are cloning green stems or woodies, remember that these cuttings are stiffer than those taken earlier in the season. That means they will be in need of supplemental humidity such as you can provide with a clear plastic hood. But it also increases their need for regular ventilation which you can provide by opening the hood daily or using an automated system. Bottom heat is not necessary in this scenario and regular misting is not usually, either. By starting the green stemmed cuttings of tropical and marginal plants now, you will have new clones ready to pot up for the indoor garden by late October. In the meantime, watch the night time temperatures and be sure they remain well above freezing. Around here, the bigger issue is keeping heat out of the rooting box on warm days and I’ve learned to make rooting boxes small enough to move with the roller coaster temperatures so common in fall. The big idea in growing woody clones is to keep air temperatures above freezing yet to increase the ventilation as the cuttings root. By growing them cool, root development is favored over top growth and a stronger clone results. Wiggle the cutting gently after a few weeks; if it resists, it is rooting and ready for a strong shot of fertilizer. In another 2 weeks, remove the hood and put the new clones in an unheated greenhouse or similar space. At this point, your job is to keep them alive with minimal watering, no fertilizer, and no repotting until spring. When they sprout new growth in the spring, it’s time to pot up and grow on.
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