Step-by-step instructions for how to propagate rosemary from stem cuttings. Includes when and how to take cuttings, encouraging root growth, and aftercare. Use these tips to create dozens of new rosemary plants for free.
If you have an established rosemary plant, you can use it to propagate dozens of new plants for practically nothing. Propagating is taking a piece of a parent plant, and encouraging it to grow its own roots and become a separate plant. The new plant will essentially be a clone of the parent plant. Rosemary is one of those herbs that roots fairly easily so if you try this method, you should have loads of new plants within a couple of months. You can also use the same technique to propagate lavender.
Though rosemary can grow from seeds, it can take a very long time. Choosing to propagate rosemary from stem cuttings is a short-cut and the most common way to multiply your plants. The best time of the year to do it is in early summer when your rosemary has new growth at the tips. By the end of summer, you’ll have baby plants to over-winter and plant out the following spring.
- Rosemary cuttings
- Rooting Hormone Powder (optional)
- Terracotta pots
- Peat-free Multipurpose compost — get from a garden center
- Plastic ziplock bag
Step 1: Source your rosemary Cuttings
You begin the process by taking a decent-sized cutting from the parent plant. It should be a healthy stem that’s grown in the current year and should be a good length as well — mine below is about 18″. If you don’t have a plant already, ask for a few cuttings from a friend who has one. I suspect that someone will eventually ask whether cut rosemary from the shop will grow. I’ve never tried it but if it’s fresh enough, I don’t see why not. If you propagate rosemary this way, please let me know as a comment.
Step 2: Potting Mixture for propagating rosemary
Some cuttings could be planted into ordinary soil and they’ll take root. Propagating this way is risky though since it heightens the chance of losing cuttings to rot, fungus, and pests.
The best potting mixture to use when propagating rosemary is one with good drainage. It doesn’t even need to be rich in nutrients either. The plants won’t need it until after the roots develop fully and you’ll re-pot them on at that time. To create good drainage I create my own mix using one part perlite and one-to-two parts multi-purpose compost. Technically you could root them in pure perlite or sand though.
Step 3: Prepare the rosemary Cuttings
What we do next is cut that single rosemary stem into pieces — each one has the potential to grow into its own plant. Starting from the bottom, trim the original cut up to a fresh leaf node. A leaf node is where leaves are growing out of the stem. Discard that end piece you’ve just cut off. Then cut the first segment using a sharp knife. It should be a minimum of 4″ long but far better to be 5-6 inches. Keep cutting until the original piece is segmented into as many cuttings as you can get.
Keep note of which end of each cutting was lower down on the original stem. This is the end that needs to be planted and if you get the ends mixed up, your cuttings won’t grow. You don’t want to plant them upside down. Now strip the leaves from the bottom of each cutting, leaving the last bunch of leaves growing at the top. This length that you strip of leaves should be about 2-3 inches long, depending on your cutting length. The part that you leave sticking up from the potting mix should be a 1.5-2″.
Step 4: Stimulate rooting
Cuttings can develop roots all on their own but if you want to start that action more successfully, use Rooting Hormone Powder. There are other materials that can stimulate rooting but this is the one I use and am happy with.
Assemble your cuttings and have your terracotta pots filled with the potting mix. Next, dip the end of each cutting into the powder and then gently slide them into the pot along the outer edge. Leave about an inch and a half between cuttings. The more professional way to slide cuttings into the pot is by making a hole with a dibber (or pencil) and then putting the cutting in that way. It’s a gentler way but I never do it that way but haven’t had any issues.
Some might question placing the cuttings around the outer edge and not in the middle. This is because they prefer a drier environment than established plants. Terracotta is a material that breathes and your cuttings will be appreciative of the extra drainage.
Step 5: Propagate rosemary
After the cuttings are arranged in the pots, give them a good drink of water and let the water drain out fully. Then place a plastic bag over the pot to make it into a mini greenhouse.
The cuttings will form good root systems within 4 to 8 weeks and during that time you need to keep the compost moist. Not sopping wet but just moist enough that you can feel it with your finger. You’ll know that your cuttings have rooted when you can see roots coming out of the drainage hole at the bottom of the pot.
Step 6: Growing on the new plants
When you spot roots, it’s time to separate the plants and put them into their own pots to grow on. First water the cuttings and then tap the cuttings and compost out. Gently tease the plants apart with your fingers and plant them up using the same one part perlite to two parts multi-purpose compost. Water them again and let them grow on for at least another month before planting them outside.
Step 7: Hardening Off the plants
Remember to always harden the rosemary plants off before moving them from an indoor to an outdoor location. If you skip this step, you could shock their systems and they can be permanently affected. Plants that don’t get hardened off can die, not grow, or just fail to thrive.
You harden plants, and rosemary plants, off by setting them out on warm sunny days and bringing them back in at night. After a week of this, they should be ready to be planted outdoors. If the weather is poor, then don’t put the unhardened plants outside. You want to gently introduce them to the world rather than give them a rude awakening.
Step 8: Caring for Rosemary
Rosemary is a hardy plant that requires very little to thrive. They’ll grow in large pots and containers as well as the ground and can eventually become as large as small trees in the right conditions. Check your own gardening zone and recommendations for caring for rosemary in your region. If you have freezing cold winters, rosemary might not survive outdoors. Planting into pots that can be taken into a sheltered place like a greenhouse or polytunnel will be your best way of keeping them alive over the winter.
Rosemary loves sunshine and needs at least six hours of it per day. It also likes sandy, well-drained soil so dig some into the ground if your soil is more clay. It doesn’t really require any fertilizer or extra nutrients.