Green Industry Resources
Hort Update- Seasonal Information for the Green Industry
Propagation With Softwood, Semi-hardwood and Hardwood Cuttings
Anyone with a green thumb knows that one of the great things about horticulture is propagation- and not just growing plants from seeds! With an understanding of basic vegetative propagation techniques, anyone can start growing all kinds of plants from cuttings. With the permission of friends, a gardener can start snipping small pieces of as many plants as they can find and experiment with the process of rooting softwood, semi-hardwood and hardwood cuttings.
Looking for a way to propagate new forsythia, lilac, potentila and viburnum bushes? These and many other types of woody plants can be propagated from softwood cuttings. Late spring is a good time to work with softwood cuttings.
Take 4-6 inch cuttings from vigorous shoots. The stem wood of each cutting should be partially matured, but not yet woody. Take more cuttings than you need to allow for some lack of rooting. The cuttings should be taken early in the morning, or a day or two after a rain, so the stem-tip portions are turgid and not wilted. Be sure to keep track of which end of the cutting is the top and which is the bottom. If you try to root an upside-down cutting it will not work!
Moisten the medium and place it in a 5-inch deep container that has drainage holes. Gently firm the medium before placing the cuttings in the container. You may want to dip the bottom end of the cutting into a rooting hormone to facilitate root formation. There are several rooting hormone products on the market and they can be found at your local nursery. Remove the leaves from the lower two-thirds of the cutting and place it in the container. Plant the cutting deep, leaving about 50% above the top of the media. Good rooting media to use include sand, perlite, vermiculite, and peat moss. No one medium or combination is ideal for all plants, but an equal mixture of peat and sand or perlite is useful in most situations.
Place the pot of cuttings in a shady area outdoors where you can check on them and where they will not be knocked over. You could also place a clear plastic bag over the top of each pot and secure it with a rubber ban around the pot's rim to hold humidity around the cuttings like a miniature greenhouse. The medium should be dampened when necessary, but not soggy or the cuttings will rot. Begin checking the cuttings in 3-4 weeks for rooting. Gently pull on 1 or 2 of each kind to check for resistance. When the cuttings have several, inch-long healthy roots, you can transplant them into separate pots to grow more roots; then place the plants in their permanent locations.
The end of summer, with fall approaching, is a good time to begin propagating semi-hardwood cuttings with plants like Artemesia, Buddleia (butterfly bush), Caryopteris (blue mist spirea), Coleus, geraniums, Lamium, lavender and many others.
Begin the process of propagation by choosing a good rooting media and buying a rooting hormone. Sand, perlite, peat moss or vermiculite are all components of a good rooting media, especially when mixed up in a 50/50 combination mixture; sand-perlite, perlite-peat moss, sand-peat moss, sand-vermicullite. The rooting media should be porous, well drained and heavy enough to firmly hold the cuttings upright. Rooting hormones can be purchased either as a liquid or powder. Several common brands are available through nurseries and garden centers. Also choose a rooting container, or pot, for the cuttings that has drainage holes and is small enough that a gallon-sized Ziploc bag will fit over the top.
To begin, take cuttings approximately six inches in length from the growing tips plants in late summer before the first killing frost. Remove all leaves from the lower half of the cutting and remove any flowers or flower buds. Dip the cut end in rooting hormone and then push the bare stem of the cutting into the rooting media. Don't allow any remaining leaves to lay on top of the soil or they will quickly begin to rot. When placing the cuttings in the container, place them far enough apart so that their leaves do not touch or overlap since leaves that touch usually rot. Once all the cuttings have been put into the rooting media, water the container to thoroughly moisten the soil and put the plastic bag over the top of the container. This will create a high level of humidity inside the bag, keeping the cuttings from wilting while new roots are being formed.
Place the container in a warm location that receives bright, but indirect sun. Avoid excessive heat or humidity build-up within the bag; if water droplets form on the inside of the bag, remove it and allow it to dry out for several hours before replacing it. Check the rooting medium for moisture every week. It usually stays fairly moist for several weeks before additional water is needed. Plant the cuttings into small individual containers filled with a coarse, well-drained soil mix, when new roots are 1/2 to 1 inch long; this will usually take 3-4 weeks. Pot the cuttings at the same depth in the new container as they were in the rooting medium. Gradually move the plants into more direct light, watering and fertilizing them as needed throughout the remainder of the winter.
Winter is a great time to talk about hardwood cuttings- those taken of fully mature plant shoots, from the end of the growing season through February and early March. These cuttings are taken from dormant plants with no signs of active growth, have no leaves and do not bend easily. The general techniques for rooting hardwood cuttings of deciduous plants are as follows.
Begin by taking cuttings from thick, healthy shoots. The cuttings should be 8-12 inches long and taken from current season growth. Remove any leaves clinging to the shoot. Make an angled cut at the top of the shoot, just above the top bud and a horizontal cut immediately below the bottom bud. (Having the cuts at the top and bottom of the cutting at different slants will indentify which side should be placed down for rooting.) Dip the bottom of the cuttings in a rooting hormone, like Rootone® , Dip-N-Grow® , or Hormex® .
At this point the cuttings can be handled in several ways. Easy to root plants like willows are often placed directly into a trench in the ground. (The trench can be prepared in the fall when the weather is still warm.) If the cuttings are 8" long, the trench should be 7" deep. Place the upright cuttings in the trench, back fill with soil and water well. In spring, check the cuttings for rooting and either pot them into containers or move them to their final location.
For plants that are slower to root or where winter conditions are very harsh the cuttings can be rooted in a cold frame or containers that are kept in a cold basement, a frost free garage or root cellar. Use sand, vermicullite, peat or other types of media for rooting. Containers should be at least 3 1/2-4" deep with drainage holes at the bottom. Insert the cuttings into the rooting media up to two-thirds of their entire length. Keep the rooting media slightly moist.
Hardwood cuttings can take several months to root, but most will be ready for transplanting into the garden by midspring of the following year. Plants very widely by species as to the best, or easiest, methods of propagation; whether is it by seeds or cuttings, softwood, semi-hardwood or hardwood. Doing a little research on individual plants before experimenting with propagation will help ensure success.