Getting new shrubs to catch from cuttings

Shrubs can be finicky creatures to get clippings to grow from, unless you're able to harvest them the right way and provide after-care while they grow. A few quick tips will make sure your clippings catch.

There are a number of shrubs — the aucuba, bluebeard, and Mexican orange among them — that root poorly from hardwood cuttings, but that respond well if semi-hard material is used instead.

If you're looking to harvest cuttings in the summer, here are some tips:

1. Take the cuttings by severing 15 to 20 centimetre (six to eight inch) side shoots from the current season's growth. These will be easy to identify — leaves will be growing on them.
2. Cut each shoot off close to the main stem.
3. Strip the leaves from the bottom part of a shoot; then cut it straight across just below the lowest leaf node.
4. Trim off the soft tip, cutting just above a leaf, to make a cutting that's 5 to 10 centimetres (two to four inches) long.

Semi-hard cuttings may root more surely if they include at the base a small wedge or portion of the parent stem. This is known as a heel, and it encourages roots to form by preventing the sap, as it flows down from the leaves, from draining away into the soil.

• Some shrubs will root very poorly — or more likely not at all — if the heel is missing from a semi-hard cutting.

1. Clip off a main shoot that carries several side shoots, but preferably without flowers.
2. At the spots where the side shoots join the main stem, remove shoots by making V-shaped incisions into the wood of the parent.
3. Use a sharp knife and cut just deep enough to include some of the cambium layer (the tissue just beneath the bark).
4. Trim the tip back to make cuttings five to eight centimetres (2 to 3 1/4 inches) long.

Once the cuttings have been taken, fill a pot to just below its rim with a light soil mix meant for starting seeds. An eight centimetre (3 1/4 inch) pot should be large enough for five cuttings, a 12-centimetre (4 3/4 inch) pot can hold as many as 10. For a really large number, a box is best.

1. Start with more than you need so that you can select the strongest for repotting later on.
2. Make a hole in the soil about one-third the length of a cutting. Insert the cutting and firm the soil gently around it. Plant the other cuttings in the same way, spaced evenly, and water well with a fine spray from a mister or hose.
3. Provide humidity by turning the pot into a small greenhouse by using a clear plastic bag and two pieces of galvanized wire about 30 to 45 centimetres (12 to 18 inches) long. Bend the wires (coat-hanger wires work) into arcs and insert the ends into the soil to form a cross-shaped support. Slip the bag over this framework and secure it below the rim of the pot with string, tape, or a rubber band.
4. You should place the propagating container in a place in a cool, dry area where it cannot be touched by frost. Beware of direct sunlight; it will cause overheating. Ideal rooting conditions for most hardy plants exist when the soil temperature is maintained at a steady 16° to 18°C.  Rooting should occur in two or three weeks.

After cuttings have rooted, they need to be acclimatized slowly. Keep them in the greenhouse or frame and raise the plastic a centimetre (1/2 inch) or so, or poke a few holes in it to let in air.

• After another week, remove the covering.
• Water the cuttings, wait one more week, and they will be ready to go into individual pots.