Propagation is how a garden grows without a garden centre. A single zinnia packet becomes a bed full of flowers; a single lavender plant becomes a hedge; a single dahlia tuber becomes a dozen plants by the end of the season. It is also how you keep the flowers you love: a rose that is no longer sold, a peony from a family garden, a dahlia in a colour you cannot find in the shops. The methods are few — seed, cuttings, division, and layering — and each suits a different kind of flower.
This guide explains each method, which flowers it suits, and the timing that makes it work. It is honest about the limits: seed from a hybrid will not come true, some flowers resent division, and some cuttings simply fail. If you are unsure whether a particular plant can be propagated legally — some varieties are protected by plant breeders' rights — check before you sell or give away the plants, and your local extension service can advise.
Growing from seed: the cheapest method
Seed is the cheapest and most generous method, and it suits annuals above all. Zinnias, marigolds, cosmos, sunflowers, nasturtiums, and sweet peas all grow readily from seed, and a single packet can fill a bed. Sow indoors for tender annuals and direct-sow for the ones that dislike transplanting, as our flowers seed starting guide explains in full. Perennials from seed are slower — many take a year or two to flower, and some, such as lavender, germinate erratically and need a cold period first. The important limit is that seed from a hybrid variety will not come true to the parent: the seedlings may be a different colour, a different height, or a different flower altogether. If you want the same flower, save seed only from open-pollinated varieties, and buy or propagate the hybrids another way. Collect seed from healthy plants only, let the seed heads dry fully, and store the seed in a labelled paper envelope in a cool, dry place.
Cuttings: cloning the plant you love
A cutting is a piece of a plant that grows into a new plant identical to the parent, and it is the method for flowers that do not come true from seed. Softwood cuttings are taken in late spring from the soft new growth of plants such as fuchsias, geraniums, penstemons, and salvias: cut a shoot about 10 centimetres long just below a leaf joint, strip off the lower leaves, and push it into a pot of moist, free-draining mix. Keep it humid — a clear plastic bag over the pot works — and out of direct sun, and roots should form in two to four weeks. Semi-ripe cuttings are taken in late summer from growth that has begun to firm up, and they suit lavender, roses, and many shrubs. Hardwood cuttings are taken in winter from dormant wood and suit roses and currants. The keys are a sharp, clean cut, a free-draining mix that stays moist but never wet, and patience — a cutting that looks dead may still be rooting below the surface, so do not dig it up to check.
Division: the perennial workhorse
Division is the simplest method for herbaceous perennials, and it is also necessary maintenance — most perennials need dividing every three to five years or they become congested and flower poorly. Dig the plant up in early spring or early autumn, shake off the soil, and divide the crown with a sharp spade or knife into pieces that each have roots and at least one growing point. Discard the old, woody centre and replant only the vigorous outer pieces. Daylilies, hostas, rudbeckia, asters, and irises all divide easily and recover fast. Peonies are the exception — they resent division, so divide them only when necessary, keep the pieces large, and expect a year or two before they flower again. Our flowers transplanting guide covers the replanting in detail. Division is best done on a cloudy day, and the divisions should be watered in well and kept moist for the first few weeks.
Layering and other methods
Layering is the method for plants that are hard to take cuttings from, such as climbing roses and some shrubs. Bend a low, flexible stem down to the ground, wound it slightly where it touches the soil, pin it down with a wire hook, and cover the wounded part with soil. Keep it moist, and by the following year it will have rooted — cut it from the parent and move it. It is slow but almost foolproof, and it works while the stem is still attached to the parent, so there is no risk of the cutting drying out. Some flowers propagate themselves: poppies and cornflowers self-sow freely if you let a few flowers go to seed, and bulbs such as daffodils and crocus multiply underground, producing offsets that can be lifted and replanted. Lilies produce small bulbils in the leaf joints that can be collected and grown on. Watch for self-sown seedlings in spring and move them where you want them, rather than weeding them out by mistake.
Timing: the propagation calendar
Seed is sown in spring for annuals and in spring or autumn for perennials. Softwood cuttings are taken in late spring and early summer, when the growth is soft and full of energy. Semi-ripe cuttings are taken in late summer. Division is done in early spring or early autumn, when the soil is warm and moist. Layering is started in spring and the new plant is separated the following year. Bulb offsets are lifted and replanted in autumn. If you take a cutting at the wrong time it will usually fail, not because you did it badly but because the plant was not in the right state — a softwood cutting taken in autumn, when the growth has hardened, will rarely root. Keep a note of what you propagated, when, and how it did, and after a year or two you will have a reliable method for every flower in your garden.
Common propagation failures — and what they mean
The most common failure is a cutting that rots: the mix was too wet, the air was too still, or the cutting was kept too warm. Use a free-draining mix, ventilate the cover daily, and keep the cuttings out of direct sun. A cutting that wilts and dies was probably too large, with too much leaf losing water before the roots formed — use shorter cuttings with fewer leaves. Seed that does not germinate may be too old, sown too deep, or kept too cold — check the packet, sow at the right depth, and give the tray warmth and light. A division that fails to grow was probably planted too deep, or the pieces were too small to survive. And a plant that grows from seed but does not look like its parent is not a failure at all — it is a hybrid showing its mixed parentage, and it may be a flower worth keeping in its own right. If you are unsure about a diagnosis, a product, or a local rule, check your local extension service — its advice is tailored to your soil, climate, and the pests and diseases active in your area.
Frequently asked questions
How do I propagate lavender?
Take semi-ripe cuttings in late summer from growth that has begun to firm up, or softwood cuttings in late spring. Lavender does not come true from seed, so cuttings are the reliable method.
Can I grow roses from cuttings?
Yes — semi-ripe cuttings in late summer or hardwood cuttings in winter. Not every rose roots easily, and a cutting may take a year to become a flowering plant.
When should I divide perennials?
In early spring or early autumn, every three to five years. Each piece needs roots and at least one growing point; discard the old woody centre.
Will seed from my hybrid zinnia grow the same flower?
Probably not. Seed from a hybrid may produce a different colour or height. Save seed only from open-pollinated varieties if you want the same flower.
What is layering?
Bending a stem to the ground, wounding it, pinning it down, and covering it with soil until it roots, then separating it. It is slow but almost foolproof for climbing roses and shrubs.