Neil Sperry: It's the perfect time to try your hand at starting cuttings

If you’re really into gardening, you’re eventually going to try your hand at starting new plants from cuttings.

It is, after all, the way that most nursery crops get their start.

Early fall is a fine time to try, so let’s look at the details by answering some of the most-asked questions:

What is a cutting?

It’s a section of a mother plant that has been severed without roots, then encouraged to form roots of its own. A cutting can be taken from a short piece of stem tissue, or it may be from only a leaf. African violets, for example, are commonly started from a leaf. Blackberries are started from root cuttings. While they already have root tissues, they must develop stems and leaves.

Which plants root best from cuttings?

Most shrubs, vines and groundcovers are started from cuttings. Many foliage plants and annuals and some perennials are, too. Trees are rarely started this way.

When are cuttings taken?

You’ll see three terms used in referring to types of cuttings. Hardwood cuttings are taken from mature, woody growth, often during the winter dormant season. Softwood cuttings are taken from fresh, succulent growth that is as young as 2 or 3 weeks old. And semi-hardwood cuttings are taken after that new growth has begun to mature (still green, no bark forming).

What is the difference between a rooting hormone and a root stimulator?

Rooting hormone powders are growth-regulating chemicals that we use to promote formation of roots where none exist.

Root stimulators are usually liquid soil drenches that you use following planting into the landscape. Traditionally, a root stimulator would have a high percentage of liquid phosphorus to promote vigorous root growth.

What type of rooting medium works best?

Most plants require ample oxygen if roots are to form freely. They also will need a constant supply of moisture to keep their tissues from drying out. The best compromise to accomplish both is to use a mix that is half Canadian peat and half coarse, horticultural-grade perlite.

How long should a cutting be?

That will vary depending on the species. For most woody plants, cuttings will be 4 to-5-inches long. With some trailing houseplants such as devil’s ivy and heartleaf philodendrons, you’ll want a short piece of stem tissue with one leaf and the short stalk (petiole) that attaches the leaf blade to the stem.

How do I prepare a cutting?

Work only with crisp, fresh tissues. Use a sharp knife or shears, and make the base cut on each stem at a 45-degree angle. That way, you’ll always be able to tell which end of the cutting was closer to the roots. That’s the portion that must be inserted into the rooting medium.

Vines and shrubs that have downward-hanging twigs sometimes have their leaves oriented upside-down. If you stick the cuttings in that way, they will never form roots properly.

Why is this a good time for cuttings?

It is still warm enough in early fall for plants to be growing well, yet it’s cool enough that the unrooted cuttings (and you) won’t wilt badly as you’re working. It’s also the time to determine which of your tropical foliage and flowering plants you want to root and keep over the winter.

How do new roots develop?

Cuttings form their new roots where the tissues have been cut, rising from the cambium layer. They will form in a ring from the base of the little cutting. You can improve your odds of good root systems developing if you "wound" the twigs gently as you prepare the cuttings. Use your knife to slice or scrape through the outer skin of the cutting. Cut an elongated shallow wedge off opposite sides of the bottom of each cutting. That exposes more internal tissue to the rooting hormone, and it will improve your rate of success.

How do you care for cuttings?

Water the cuttings thoroughly and place them in a bright spot that’s out of direct afternoon sun. If they wilt badly, cover them with a sheet of drycleaner’s plastic to hold in the humidity. When you can feel slight resistance to gentle pulling, your cuttings will be rooted and can be potted up individually.