A relatively easy way to propagate new plants is by rooting stem cuttings. Success is better achieved by using a good potting medium, a sharp clean cutting tool, and a rooting hormone.
Types of stem cuttings
There are three types:
- Softwood are new stems developing in spring on existing branches. They are typically referred to as “this year’s growth” and taken in spring and early summer…late May through June.
- Semi-hardwood are stems which are nearly mature. These are the type of cuttings taken in mid-summer…mid-July through early August.
- Hardwood are stems which are fully mature. These are the type of cuttings taken in late summer and early fall…mid-September through early October.
- clean pot or tray with plastic bag or lid for cover
- soilless growing medium*
- cutting implement
- rubbing alcohol or 10% bleach solution for disinfecting
- rooting hormone**
- cuttings – cut 4-6 inch (10-15 cm) long branches from tips of healthy plants; make cuts mid node (between leaf nodes)
- container of water to hold fresh cuttings
- pencil or thin dowel
- Disinfect pot, cover, and cutting implements.
- Select healthy plants for your cuttings.
- Cut stems just below a leaf node and place them in your container of water to keep hydrated.
- Fill clean pot with growing medium and moisten slightly.
- Take one of your stem cuttings out of the container and make a clean cut right below a leaf node…if you did not make a clean cut at the leaf node when cutting your stems.
- Remove bottom leaves from stem cutting, leaving 2-4 at the top. If leaves are quite large, cut in half to reduce weight so stems will remain upright in pot.
- Remove any flower buds, flowers, and/or fruits from the stem cutting.
- Pour a small amount of rooting hormone in a small cup or lid. Moisten stem tip in water and dip it in rooting hormone. Be sure to coat bottom half-inch or inch (1.25-2.5 cm) of stem.
- Poke a hole in your growing medium, wide enough to plant stem without touching sides of hole to prevent dislodging the rooting hormone.
- Place stem in hole, at least 2 inches (5 cm) deep. Tamp soilless medium around cutting to provide good contact for root development.
- Cover pot with plastic bag or cover tray with plastic cover to keep cuttings hydrated. You may want to remove the cover for a few hours periodically in order to allow some air to circulate around the cuttings and decrease chances of powdery mildew forming.
You should have roots on softwood cuttings in four to six weeks. Semi-hardwood cuttings should have roots in six to eight weeks. Hardwood cuttings take three to four months, or longer, to develop a good root system.
Best to use a soilless mix such as perlite, vermiculite, sand, or a combination of a soilless seed starting medium with perlite or vermiculite or sand mixed in. I generally use seed starting soilless mix with a generous addition of perlite mixed in to improve drainage. DO NOT use soil from your garden beds or compost as they contain many soil organisms such as fungi and other pathogens which can be deadly to stem cuttings…and young seedlings too for that matter.
All plants contain a natural rooting hormone called auxin which not only stimulates growth but also signals a bud when not to grow. This helps stem cuttings develop new roots from the cut leaf node.
However, there are products on the market that will help the process. Synthetic auxins have been on the market since the 1930’s. The ones available to home gardeners contain chemicals such as indolebutyric acid (IBA) in alcohol or a-naphthaleneacetic acid (NAA) in talc. The dry hormone preparations usually contain fungicides to help prevent powdery mildew on the cuttings. These are not allowed under certified organic criteria.
We use the NAA rooting hormone and there are three types…each specifically manufactured to use with one of the three types of stem cuttings:
- #1 is used with softwood stem cuttings.
- #2 is used with semi-hardwood stem cuttings.
- #3 is used with hardwood stem cuttings.
For more details about stem cuttings and materials needed, check out this blog posting here.