Make More Thyme for Your Garden

9 July 2015, written by Ann Marie Hendry

Thyme is of course essential in the herb garden, but its usefulness elsewhere means it’s well worth knowing how to propagate your own so you can use it all around the garden. Who can resist free plants, after all – particularly when they’re so attractive to both gardeners and bees?

Like lavender, thyme has a tendency to go a bit woody after a few years, so by occasionally propagating your plants you will ensure a steady supply of leaves while keeping your garden looking great.

Growing from seed is the most obvious method of propagating thyme but it’s also the hardest. Germination is slow and unreliable, so I don’t recommend this unless you’re very patient, or stubborn! Taking softwood cuttings, layering and dividing are far easier methods.

Softwood Cuttings of Thyme

Softwood cuttings can successfully be taken from spring right through the summer. Prepare your containers first – a 50:50 mix of potting compost and sand works well. Then, select the shoots you want to take cuttings from. They should look healthy and be non-flowering. Use a sharp knife to take a cutting about 5-10cm (2-4in) long just below a node (the point where leaves sprout from the stem). Strip the leaves from the bottom half of each cutting. Now make a hole in your growing medium with a dibber or a pencil and pop the cutting in so that the half with the leaves remains above the surface.

Pop the cuttings into a propagator. A heated propagator is ideal, but an unheated one will work – the cuttings will just take longer to root. If you don’t have a propagator, simply pop a clear plastic bag over the pot to create a humid environment. You can use an elastic band to hold it in place. Remove the cover daily to let in fresh air.

Put your cuttings somewhere out of direct sunlight and keep the potting soil moist. It will take several weeks for roots to form. When you can see new growth starting, pot the cuttings on into their own containers.

Layering Thyme

Layering is usually started off in spring or autumn, but I’ve had success with this method during summer too. Take a low-growing branch of a healthy thyme plant and strip off all the leaves, leaving just a few at the tip. Remove any sideshoots. Pull the stem gently down to ground level and dig a shallow trench where the stem touches the ground. Use a sharp knife to make a small wound on the stem where it makes contact with the soil, as this will encourage rooting – be careful, though, as the stems are very thin and easily broken.

Use a piece of bent wire to fix the stem loosely to the ground, then backfill the trench leaving the end of the stem pointing up out of the soil. Tie the tip to a small cane to coax it to grow upwards. As with any new planting it’s essential to keep the soil around the layer moist, particularly in summer.

The layer should develop a sturdy root system within about a year. Dig up the layer and make sure it has a good root system before snipping it away from the parent plant. You can then replant it elsewhere, or pop it into a container.

A slight variation on simple layering is mound layering, where soil or compost is heaped over the plant, with just the tips of the stems left poking through. After several months roots will have formed along the stems, and they can be cut off and replanted. The original plant can then be dug up and composted.

Dividing Thyme

Thyme can be divided in spring or autumn. Some say that spring is the best time, with warmer weather and longer days helping the divided plants to leap into growth, but I have good results with autumn divisions as they have the whole winter to rest and put down roots before the growing season resumes.

To divide thyme, dig up the whole plant and break it into sections. Three or four divisions per plant is usually enough as small divisions take longer to establish than larger ones. If the plant is reluctant to pull apart in your hands, use two hand forks back-to-back to prise it into sections. It’s worth cutting back the foliage by up to a half to reduce water loss as the plant re-establishes itself. Then simply replant your divisions where you want them to grow.

Varieties of Thyme to Try

All thymes make excellent container plants due to their preference for poor, dry soils. There are lots of varieties to try, with a delightful range of colours, but there are three distinct species that have their own special areas of expertise.

Common thyme (Thymus vulgaris) is an unfussy and hardy plant. It’s excellent as part of a herb garden, used to soften the edges of paths, planted into the tops of raised beds to spill over the edges, or in rock gardens.

Lemon-scented thyme (T. citriodorus) is less hardy than common thyme – mine didn’t even make it through the winter in a greenhouse, and it wasn’t a particularly cold winter. If your climate is warm or you’re prepared to cosset it through the colder months it’s great for tall containers or hanging baskets, at a handy height to enjoy the divine lemon sherbet scent.

Thymus serpyllum, or creeping thyme, is perfect for a low-growing, flowering lawn, which will be abuzz with bees. It’s also excellent for placing in gaps between paving slabs, where walking on it will crush the leaves and release the scent, or in green roofs.

Where are your favourite places to grow thyme in your garden? Let us know by dropping us a comment below.