Propagating Herbs

By ACS Distance Education on March 12, 2015 in Animals & Herbs | comments

Creating new plants from old is not only fascinating and simple, it’s also the most economical means of adding to your garden.

Propagating your own herbs can be one of the most addictive and rewarding of gardening pursuits. It’s really quite easy once you know how.

The annual herbs are normally propagated by seeds. Biennial and perennial herbs can also be propagated by seed, though other techniques such as division or cuttings are frequently used. Some herbs (including tarragon and certain mints) rarely produce seeds, making propagation by division or cuttings the only alternative. Selected varieties of herbs grown for both commercial cropping or home garden use, are often propagated by division or cutting, ensuring the new plants have the same characteristics as the parent. Some perennials (e.g. Fraxinella) are best propagated by division or cuttings because of slow seed germination.

A reliable source of seeds is essential when propagating. Dealers usually handle the varieties which are in high demand but it is often difficult to obtain seed for the less common varieties or when you do, there is no guarantee you’ve got the herb you wanted. You can usually depend on the varieties of parsley and chives you buy but the mints, thymes and sages can sometimes be different from what their labels indicate. The best advice is to double check the credibility of suppliers and still be suspicious of the accuracy of the naming of seeds until you have grown and checked the plant yourself.



Some herbs such as chives, creeping thymes and mints form clumps or mats which can be divided to form new plants. Divide by placing two forks into the clump and separating. Rock the forks back and forth as you pull to loosen the soil and tangled roots. Try to avoid tearing which might damage roots. Some nurserymen cut clumps with a spade or knife but this exposes cut tissue to infection and while this is less desirable than the other method, most hardy herbs will resist infection through cuts.

Stock plants are best grown in a sandy or loose soil in containers such as buckets or 3.5 gallon tubs. The divisions will separate easier than in a clay soil. Other herbs which grow readily from division include: Salad Burnet, Germander, Horehound, Orris Root, Lemon Balm, Pot Marjoram, Sorrel, Tansy, Violets, Sweet Woodruff and Yarrow.



Woody herbs such as Sage, Lavender, Rosemary, Santolina, Lemon Verbena and Bay, are commonly grown from cuttings. Cuttings are normally 5-7 cm semi-hardwood (taken late January to April) with rooting hormone. Cuttings are inserted into either growool propagating blocks, or in a 75 % sand/25 % peat mix (in plastic pots or trays) and placed in a greenhouse, cold frame or better still, a heated propagating bed. These plants can take anything from one to seven months to form roots. When roots form they can be potted up into tubes or larger pots.



Layering involves pinning a branch or stem down to the ground (perhaps with a small wire peg) and covering a section with soil. Over a period of time, roots will develop on the section of stem below the soil. Once a reasonable root system had developed, the layered section can be cut off the original plant and potted up into a container.

Herbs which grow easily from layers include: Lemon Balm, Marjoram, Mint, Savory, Tarragon, Thyme, Santolina and the Sages.



Seeds are normally sown in spring after the frosts have finished. May herbs can be sown direct into the soil outdoors. A few of the more difficult types may be better sown in a glasshouse or cold frame (i.e. as outside box with a glass or plastic lid). Most seed-grown herbs can be started earlier by sowing outdoors.

Provided the temperature is adequate (18 to 25 °C for most), seeds will germinate and young seedlings will grow at any time of the year.

The seeds of Flaxinella, Sweet Cicely and Lovage should be sown in late summer as soon as they are ripe.

In an established herb garden, many varieties will self seed, so much that they can even become weeds.

The following varieties are notorious for slow seed germination: Good King Henry, Lavender, Lemon Balm, Wormwood, Rosemary, Sweet Woodruff. Parsley seeds are known to be slow germinating but our experience would disagree, provided the seeds are fresh.

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