Given the right conditions, plants can be persuaded to root from stem cuttings in spring or summer, or in winter from pieces of root. Seal collected cuttings and root material in a plastic bag to keep them fresh.
With the exception of variegated plants, which produce only green shoots from root cuttings, many perennials can be propagated using this method. Never take more than a few roots from each plant, and quickly replace the plants in the soil. Thin roots, such as those of phlox (Phlox paniculata), should be laid horizontally on the soil to root.
|Anemone x hybrida||Bear’s breeches, Acanthus|
|Dicentra||Globe thistle, Echinops|
|Plume poppy, Macleaya||Oriental poppy, Papaver orientale|
|Sea holly, Eryngium||Tree poppy, Romneya|
Trim off healthy roots
In midwinter, lift the plant, or scrape away soil from larger plants to expose the roots. Cutting close to the stems (crown), remove three or four fat, healthy roots, avoiding brittle, damaged, or woody pieces. Seal in a plastic bag.
Cut top and bottom
Cut each root into 2–3 in (5–8 cm) segments with a sharp knife. Trim the top end (nearest the crown) straight across and the bottom at an angle, to make sure you plant them right end up. You do not need to do this with thin roots.
Insert the root cuttings vertically in pots of soil (with the blunt end at the top), spacing them 2 in (5 cm) apart. Lay thinner roots on the surface, covering them with. in (1 cm) of coarse sand or grit. Water the roots with diluted fungicide and move pots to a sheltered spot outside.
Cover pots and trays with fleece, or place them in a cold frame, and keep the soil damp. The cuttings should be well rooted in about six months. They may produce shoots beforehand but wait until roots appear at the holes at the bottom of the pots before transplanting.
These are the easiest cuttings to grow, but you need patience, as rooting can take
more than a year. Find a sheltered spot where the cuttings won’t be disturbed, such
as the back of a border. Use this method for deciduous shrubs, trees, roses and fruit.
Take a healthy stem
In autumn, select straight stems, about the thickness of a pencil and with plenty of buds, taken from the current year’s growth. Strip off any leaves and side shoots. You may be able to take several cuttings from a single stem.
Cut into sections
Make individual cuttings about 10 in (25 cm) long. Cut straight along the bottom just below a bud, and make a slanted cut above a bud at the top. The cuts differentiate the top from the bottom, and allow you to plant the right way up.
Plant in ground
Make a narrow V-shaped trench by inserting a spade about 8 in (20 cm) in the soil and pushing it forward. On heavy soil, add horticultural sand to the base to aid drainage. Insert cuttings 6 in (15 cm) apart, leaving a few buds above the surface. These will form the branches of the new shrub. Firm lightly, label, and water.
For less hardy plants, such as Cistus, Perovskia, and Santolina, plant cuttings in pots of free-draining soil. Trim cuttings to 3–4 in (8–10 cm) long and plant with the top bud exposed. Protect from frost by placing pots in a cold frame or unheated greenhouse until spring. Plant in autumn once rooted.
|Boxwood, Buxus||Butterfly bush, Buddleja|
|Flowering currant, Ribes||Mock orange, Philadelphus|
|Rose (including bush types)||Spiraea|
Nonflowering shoots of many tender perennials and patio plants, as well as some herbaceous perennials, including delphinium and lupin, will root in six to eight weeks in warm, humid conditions in summer. Cuttings are prone to disease, so sterilize any knives, pots, and trays used in their preparation, and root them in fresh, sterilized soil mix. Use tap water for cuttings.
Select healthy stems
In summer, collect healthy, leafy shoots, about 3–5 in (7–12 cm) long, from plants that you have watered well the evening before. Take your cuttings in the morning, before the plants are stressed by high temperatures, and seal them in plastic bags to keep them fresh.
Take off lower leaves
Pre-fill pots and trays with moist cutting soil mix to avoid any delay once cuttings have been prepared. Using a sharp knife, cut just below a leaf joint and trim off lower leaves neatly to leave just two or three healthy ones at the top. Dip the cut ends in hormone rooting powder.
Push the cuttings into the soil mix, leaving the upper half exposed. Root singly in small pots or fit several into large pots or trays, making sure the leaves are not touching. Firm lightly, water, and cover with a clear plastic bag, or root in a propagator, and keep at 59–70°F (15–21°C).
These are gathered later in summer when the bases of the stems are firmer. You can pull off side shoots with a little tear or “heel” of stem, and they will root in about ten weeks, or the following spring. This method is used mainly for evergreen shrubs, like boxwood (Buxus), and woody herbs, such as sage (Salvia).
Choose a healthy stem
Select shoot tips or side shoots that are firm at the base, soft and leafy at the top. Cut just below a leaf joint or gently pull side shoots downward to leave a heel of stem tissue still attached.
Prepare the stem
Use a sharp, sterilized knife to trim off the soft shoot tip just above a leaf joint. Discard this section. Removing the shoot tip helps reduce moisture loss from the cutting.
Remove lower leaves
Remove the leaves and side shoots from the lower half of the cutting, and trim back any heels at the base that are particularly long. If your cutting has no heel, simulate one by cutting a 1 in (2.5 cm) slice from one side of the stem.
Dip the cut ends in hormone rooting powder. Either root in pots of moist cutting soil mix, inserting them up to the base of the lower leaves, or set hardy types, such as boxwood 3 in (8 cm) apart in sandy soil in a cold frame.
Place your pots of cuttings in a covered propagator set to 64–70°F (18–21°C), or seal them in clear plastic bags, propped up with sticks to keep the plastic off the leaves. Keep soil moist. Harden off and plant out once rooted.