How and when to take rosemary cuttings

I chatted with Olivia Steed-Mundin, kitchen gardener at the National Trust’s Sissinghurst Castle Garden, in Kent, where she looks after the spectacular four-acre (1,600 sq m) organic vegetable garden. She has shared her top tips on how to take rosemary cuttings and the best time to do it.

Steed-Mundin says, “Rosemary cuttings are easy to do, so this is an ideal project for beginner gardeners. There is usually between a 50 and 70% success rate with rosemary, which is quite high. So if you want, say, five plants, take about 10 cuttings.”  

What you will need to take a rosemary cutting: 

• Secateurs/scissors 
• A dibber or pencil 
• Free-draining, peat-free compost 
• 9cm (4in) pots  
• A rosemary bush 

“The best time of year to take a rosemary cutting is between late summer and early autumn,” Steed-Mundin suggests. We’d say August and September are prime months for taking cuttings.

She also explains that the best time of day is early in the morning because that is when the moisture in the plant tissue is at its highest.  

You can also grow lavender from cuttings at this time of year

Before you start, sterilise your equipment. Rub down secateurs or scissors with an alcohol–based gel or spray, which will help prevent spreading fungal problems. Also, for the same reason thoroughly clean your pots.  

I use a supermarket antibacterial spray (such as Dettol) when I clean my equipment, but it can cause your secateurs or scissors to turn rusty prematurely if you don’t wipe them afterwards, so take care to do this properly.

The ideal compost for rosemary cuttings, according to Steed-Mundin, is a well- drained, light compost with plenty of air in it. “I use a 50:50 mix of a seed compost with perlite,” she explains. “This ensures there is plenty of air around the roots when they develop and that there is less chance of the stems rotting.”

Steed-Mundin advises that the final length of the cutting should be 10 -15cm (4 -6 in). “It is best to choose cuttings slightly longer than this so they can be trimmed down,” she continues.

“Cuttings that are nice and upright, will make well shaped plants,” she adds. “Take them from healthy, non-flowering sections of the bush. The base of the cuttings should be just turning woody and the remainder should consist of young green growth. These are called ‘semi-ripe’ cuttings.”

The cuttings need to be trimmed, top and bottom with secateurs or a knife so that their final size is 10-15cm (4-6in). Make the lowest cut just below a pair of buds. This is the best place to stimulate potential new roots.

Steed-Mundin adds that you should also trim the floppy tip of the shoot back by about 2cm (1/2in).

Before inserting the cutting into the well- drained compost, remove the lower half of the leaves or the lower two or three ‘whorls’ of leaves.

Steed-Mundin says, “It is important to remove the lower leaves that would otherwise be in the compost or in contact with the surface, because they will rot.”

Use a dibber (or pencil) to make holes 3-4 cm (1-1 1/2in) deep into the compost and then carefully insert the lower part of the cuttings, ensuring the foliage is not buried.

Steed-Mundin suggests that the cuttings can then be gently firmed in and lightly watered to wash the compost gently back around the stem. She uses 9cm (3.5in) pots and places five or six cuttings around the edge. This ensures that by the time they are ready to be ‘potted on’, the roots won’t have become tangled.

Leave the cuttings in a relatively warm place such as a windowsill or cold frame, but not in direct sunlight, which will scorch the foliage and cause the compost to dry out.

Steed-Mundin explains that cuttings root fairly easily so there is no need for a propagator or to cover them with a plastic bag. In fact, this may be detrimental because rosemary does not like humid conditions.

Rosemary cuttings should be ready in six to eight weeks. Steed- Mundin says: “You know when the cuttings are ready because they start to make new growth from the tip and nodes.

“You can also test if they are ready by giving them a gentle tug and feeling any resistance. If there is, it means they have established roots and are ready to be potted on. You can also lift up the pot and look through the drainage holes to see if you can see any signs of roots.”

Once established, cuttings can be gently removed and planted into individual pots.