How to Propagate Sweet Marjoram from Cuttings, Division and Seed

Cuttings are the way to beat the frost

With oregano, propagation is optional maintenance because the parent plant will be there next year anyway. With marjoram it is the whole game. The plant you like will be killed by the first hard frost, so if you want it again you either save seed, lift the whole plant into a pot, or take cuttings in late summer and overwinter small rooted plants on a windowsill.

Cuttings win for most people. A rooted cutting in a three inch (8 cm) pot takes up almost no windowsill space, needs very little water through the winter, and is far less likely to bring spider mite indoors than a big lifted plant. Take six and you will keep three, which is more than enough.

Taking cuttings, and the timing that decides whether they root

Marjoram roots easily from soft young growth, and much less easily once the stems begin to harden and the plant starts making flower knots. That is the timing decision: a cutting taken from a shoot that has already knotted is putting its energy into buds, not roots, and failure rates rise sharply.

For the overwintering cuttings, take them in late summer while nights are still warm but well before the first cold snap. They need six weeks of warmth to root and settle before the light drops. Cuttings taken too late sit there through the winter without rooting and slowly rot.

1. Choose non-flowering tips Take four inches (10 cm) from a shoot with no knot at the end. If the whole plant has knotted, cut it back by a third, wait three weeks and take cuttings from the clean regrowth.
2. Cut just below a leaf pair Roots form at the node. Trim the base cleanly immediately below a pair of leaves and strip every leaf from the bottom two inches (5 cm).
3. Insert into a gritty mix Half compost, half perlite or sharp sand. Five or six cuttings around the edge of a small pot, watered once, then kept only just moist.
4. Bright shade, and no plastic bag Unlike many soft cuttings, marjoram rots under a sealed cover. Bright indirect light with air moving around the pot is what it wants. Aim for 65 to 75F (18 to 24C).
5. Test at three weeks A gentle tug that meets resistance means roots. Pot rooted cuttings on individually into three inch (8 cm) pots of gritty mix.

Cuttings will root in a glass of water on a windowsill, which is tempting, but water roots are brittle and a high proportion collapse when potted into compost. Rooting straight into a gritty mix takes a week longer and gives a plant that actually survives.

Keeping the young plants alive through winter

Overwintering rooted cuttings is mostly a matter of resisting the urge to look after them. They are barely growing, they are in low light, and every extra milliliter of water and every dose of fertilizer works against them. The commonest way to lose them is kindness in the depths of winter.

Give them the brightest cool windowsill you have, ideally somewhere that stays between 50 and 60F (10 to 16C). A warm room pushes weak drawn growth that attracts spider mite. Water only when the mix is dry an inch (2.5 cm) down, which in midwinter may be once every two or three weeks, and give no feed at all until the days visibly lengthen.

1. Bright and cool, not warm An unheated but frost-free porch or a bedroom windowsill beats a heated living room. The plant is resting and warmth without light is what ruins it.
2. Water sparingly, from below Check by weight: a dry pot is noticeably light. Water into a saucer, let it take up what it needs for ten minutes, then pour the rest away.
3. Check the undersides weekly Spider mite is the main winter risk. A weekly look at the leaf undersides catches it while a rinse under the tap is still enough.
4. Pinch once in late winter As the light returns and the first new shoots appear, pinch the tips to build a bushy plant before it goes back outside.
5. Harden off before planting out Give it a week outdoors in a sheltered spot during the day only, then plant out once nights hold above 50F (10C).

Division and layering, and when each is worth it

Division only applies where marjoram lives long enough to make a clump, which means a frost-free or nearly frost-free climate. If you have a plant that has come through two or three winters outdoors, lift it in spring as growth starts, discard any woody center, and split the outer sections into fist-sized pieces with roots and shoots on each. Trim the top by half before replanting so the divisions do not wilt.

Layering is the fallback for anyone who cannot get cuttings to root. Marjoram stems root where they touch damp soil, and because the shoot stays attached to the parent while it roots, it cannot dry out. Choose a long low outer stem, strip the leaves from the middle section, pin it to the soil with a wire staple, cover it with an inch (2.5 cm) of gritty soil and leave the tip exposed. Check for roots after six to eight weeks, then sever it from the parent and lift it a fortnight later.

Layering is worth starting in midsummer rather than late, so the new plant has roots and can be lifted and potted for the winter before cold weather arrives.

Seed is fine here, unlike with oregano

Oregano seedlings vary so much in scent that raising it from seed is a gamble. Sweet marjoram is far more consistent, and because most people grow it as an annual anyway, seed is a perfectly sensible route and by far the cheapest way to fill a bed. You still get some variation in vigor and sweetness, but nothing like the range oregano throws.

Use seed when you want quantity or are starting from nothing, and use cuttings when you have a particular plant whose flavor you want to keep exactly. The two are not in competition: sow a tray in late winter for the bed, and take cuttings in late summer from whichever of those plants turned out best.

Keep track of which plant came from which

Label the cuttings with the parent plant and the date you took them. Once you start overwintering, plants accumulate, and by the second spring you will have plants of two or three different ages and origins that all look identical in a pot but perform quite differently in the ground.

Record how many cuttings you took and how many rooted, along with the date. Marjoram cuttings taken a fortnight too late root markedly less well, and after two seasons of notes you will know the right week for your own garden rather than working from a general rule.