Instead of purchasing a new rosemary plant every year or starting new plants from seeds, try growing your own from stem cuttings. It is easy to take rosemary cuttings from an established mother plant and grow new rosemary plants in containers that can be moved outside in summer and indoors in winter.
A rooted rosemary plant from a cutting will mature quicker than a plant started from seed. The plant will reach a usable size in just a few months so you will be able to harvest rosemary sooner. The rosemary plant you will grow from cuttings will be an exact clone of the mother plant and have the same flavor, disease resistance, and growth. A single plant can provide numerous cuttings without risking the health of the plant. So you can line your kitchen windowsill with several plants that will smell wonderful when you brush your hand against them.
Rosemary (Rosmarinus officinalis) is a perennial herb in USDA Hardiness Zones 8 and warmer where it can be planted in the garden and can grow 4 feet tall and spreads about 4 feet wide depending on the variety. For those of us gardening in colder zones, growing rosemary in containers allows us to bring it in during the winter.
My rosemary plant is going on four years old this year. It grows in a container and spends the summer outside and is relocated inside when the weather turns cold to overwinter on a south-facing windowsill. By the time spring rolls around, the plant usually looks raggedy from reduced light and heat fluctuations. Sometimes so many needles dry up and drop off that I wonder if the plant can possibly survive.
When warmer weather arrives, the rosemary plant is hardened off, and returned outside. Soon after, it begins to grow new shoots and the branches fill in with thicker foliage. I am amazed every time it happens.
The old rosemary plant is looking pretty ugly from being hacked and trimmed over the years. Now that spring is here and the sunlight has increased, the plant is sending up some new shoots. Now is a great time to start a new batch of plants. These fresh, green stems are the ones you want to select for softwood stem cuttings.
How to Propagate a Rosemary Plant from Stem Cuttings
1. Select new shoots from the mother plant. Choose healthy stems with fresh growth. The younger shoots will have green stems that are flexible. Avoid older brown, woody stems.
2. Take cuttings. Using sharp scissors, snip the rosemary stem about 5 to 6-inches back from a fresh growing tip. Cut a few extras in case some fail to grow roots.
3. Strip the lower leaves. Using your fingers, gently strip off the lower 2-inches of needles from the rosemary cutting.
4. Place cuttings in water. Stick the stems in a jar of water and locate in a warm place away from direct sunlight. Change the water every couple days, replacing with room temperature water. The fresh water provides dissolved oxygen and prevents the cuttings from rotting. The rosemary stem cuttings should grow roots in a few weeks depending on the temperature. It can take longer in colder temperatures. After 4 to 8 weeks it should be apparent if the rosemary cuttings have survived. The cuttings that do not survive will be brown and shed needles.
5. Pot up the stem cuttings once roots develop. Use a sandy soil mix that drains well. Mix equal parts all-purpose potting soil and sharp sand. Or use cactus-potting soil. Fill a 4-inch pot with slightly damp potting soil for each rosemary cutting. Use a pencil to make a 3 to 4-inch hole into the soil. Place the cutting in the hole with care to avoid damaging the roots. Cover gently and water thoroughly. Place indirect light or in filtered sunlight until roots become established then move to direct light, at least 6 to 8 hours per day. Keep medium moist until you see new growth, but don’t over-water.
6. Water when the soil feels dry. Once established, rosemary likes to stay on the dry side. Allow top inch of soil to dry out between watering, and then water thoroughly. Over watering will cause the plant to rot.
7. Caring for your new rosemary plant. Allow the new plants to put on some growth before harvesting. Once the plant is 6-inches tall, harvest by cutting stems as needed. New growth will continue forming on the stem. Rosemary grows slowly so don’t harvest more than 1/3 of the plant at one time. Re-pot as the plant gets larger and the roots fill the container.
A rosemary plant that grows in a container can reach 1 to 3 feet high. Just keep transplant to a larger container when the roots fill the pot. The more you trim, the bushier the plant grows. Prune the plant after it flowers in June or July to keep it compact.
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