Dividing plants by division is one of the most important methods of propagating plants. This method will give even the inexperienced gardener a 100 percent success rate.
What types of plants lend themselves to division?
Plants that work well being divided usually form mats, tufts, or clumps, and include many perennials, alpines, water plants, and even some suckering shrubs such as kerria. Some plants dislike being disturbed. This type includes the peony and Christmas rose, and those plants with thick main roots, but few fibrous roots, such as the oriental poppy and lupine.
In addition to increasing the number of plants, dividing is a good way of rejuvenating an old clump, by retaining and planting the young rooted pieces from the outer edge and discarding the older woody center. Division is carried out in either the fall or in the spring. I prefer the spring when the plants are just starting to grow, the weather is improving, and they have the whole summer to produce a large plant before they die down for the winter.
How to divide a plant.
Dig up the clump when the foliage is starting to grow, taking care not to damage the roots. Remove any surplus soil. Clumps with fibrous roots that are not matted together may be teased apart, separating them into small pieces of plant complete with roots. You can prize apart dense clumps using garden forks or, in some cases, solid masses of hostas can be cut with a knife or a spade. Any plants that have become infested with perennial weeds should not be used. Since it is difficult to separate the roots, and if one piece of wed root is missed, it can grow away, protected by the plant.
Replant the new plants as quickly as possible to prevent their growth from being checked by a long spell out of the soil. Plant them in well-cultivated soil, free of weeds and dressed with some bonemeal. Water the plants in, to settle the soil around the roots.
Growing from cuttings
Taking and rooting plants from cuttings is the most satisfactory gardening job of all. There is real pleasure when you ease a piece of plant out of the soil and see the mass of roots. It is particularly satisfying to be able to root plants that are listed as difficult. Years later, you will still remember the plant you rooted and where it came from before it ended up in your garden. There is a story behind every plant you manage to propagate this way.
Softwood means exactly that; you use the current year’s shoots that are soft but not floppy. You cut them about 2-4” long in late spring and early summer, before the stem becomes hard and woody, and root them in a container of medium, covering them with clear plastic to prevent wilting. When they are rooted, which can be in as short a time as six weeks, they can be repotted or planted out in the garden.
This is a quick, cheap way to increase a whole range of shrubs, perennials, and alpines, especially if you have a good source of cuttings. Friends with gardens are usually only to pleased to offer pieces, and if you ask your local park manager he might cut you some suitable stems. The one thing that you must not do, of course, is to take cuttings without permission in anyone else’s garden.
These plants can be easily rooted by taking softwood cuttings: Choisya, Deutzia, Escallonia, Fuchia, Hebe, Hydrangea, Lavender, Olearia, Philadelphus, and Weigela.
Rooting hardwood cuttings is a simple, cheap, and effective way of propagating. You won’t even have to provide protection from the elements.
Hardwood cuttings are taken in late fall and winter when the stems of that year’s growth have hardened up and, if the plant is deciduous, all the leaves are off. This method of propagation is used for shrubs and some trees. The cuttings should be about 12” long and inserted in open ground in a sheltered part of the garden. The cuttings take longer to root than softwood cuttings, producing well-rooted young plants after a year- ready for planting out in their final position in the garden or potting them up.
Sometimes this is referred to as semi-hardwood, and is rooted between midsummer and fall, using cuttings from the current season’s growth when the base of the cutting is becoming woody but its top is still soft. Prepare and root as for softwood cuttings.
This is used to propagate hardwoods when plant material is scarce. The stem should be fully ripened wood after the leaves have fallen, and as thick as your little finger. Cut with sharp clippers 1inch on each side of a plump bud. Dip the lower end into hormone rooting powder and insert it in seed or cutting medium with extra grit or coarse sand added for drainage. Keep the bud level with the surface of the soil. Alternatively, slice away a strip of bark from the length of stem opposite the bud and coat the bare stem with hormone rooting powder. Lay the cutting horizontally in the soil with the bud exposed, and it will root along the length of the cutting.
Increase stock of thick-stemmed house plants such as dracaenas, dumb cane, and cordyline. Select a healthy stem and cut it in lengths, with at least two nodes or rings where the leaf is produced. The cutting can be as small as 2 inches and you can insert it vertically or horizontally in moist medium with the nodes showing. Water the cuttings and keep them in a warm humid area. The new leaves will appear at the nodes, and the rooted plant can be potted up.
Pipings are taken in late summer from carnations and garden pinks. Gently pull the tip out from the main stem above a leaf node and remove the lower leaves to leave the cutting with four pairs of leaves. Dip these “pipings” into hormone rooting powder and insert them around the edge of a pot of free-draining gritty soil. Screen the cuttings from strong sunlight and don’t allow the soil to dry out. You will have young rooted plants within a month.