How to propagate rosemary from stem cuttings. This method helps you to create dozens of new plants for free. Includes a DIY video at the end
If you have an established rosemary plant, you can use it to propagate dozens of new plants for practically nothing. Propagating is essentially cloning the parent plant and the way that happens is by encouraging pieces of the stem to form their own roots. 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.
- Rosemary cuttings
- Rooting Hormone Powder
- Terracotta pots
- Peat-free Multipurpose compost — get from a garden center
- Plastic ziplock bag
Step 1: Source your 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.
Step 2: Potting Mixture
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 plants 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 two parts multi-purpose compost. Technically you could root them in pure Perlite or sand though.
Step 3: Prepare the Cuttings
What we do next is cut that single rosemary stem into several pieces. Each one has the potential to grow into it’s 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 3″ 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 the cutting leaving the last bunch of leaves growing at the top. This length that you strip of leaves should be about 1.5-2.5 inches long, depending on your cutting length. The part that you leave sticking up from the potting mix should be a miniumum of 1.5″.
Step 4: Rooting Hormone Powder
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 hormone 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 why place 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: Propagating
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
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
Remember to always harden 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 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 very 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.
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 naturally more clay. It doesn’t really require any fertlizer or extra nutrients but saying that, I top dress mine with composted manure in the spring if I remember.
If you have freezing cold winters take note that 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.