If you’re wondering how to grow rosemary, you’ll be happy to learn it’s a low-care culinary herb that is productive, attractive, and resistant to drought, pests, and deer. It’s easy to grow in garden beds and containers, thriving in full sun and well-draining soil. The needle-like leaves of rosemary are packed with fragrant oils that add mouthwatering flavor to a wide variety of dishes. This classic kitchen herb is essential for anyone who loves to cook and if you want to learn how to grow rosemary, I’ve got plenty of in-depth advice and tips below.
Get to know rosemary
Rosemary, Rosmarinus officinalis, is an evergreen shrub native to the Mediterranean region, growing particularly well in the rocky soil along the sea. It’s a tough plant that stands up to sun, wind, heat, salt spray, and when established, drought. Rosemary is even resistant to insects, deer, and rabbits. It’s a winter hardy perennial in USDA hardiness zones 8 to 10, although there are a few cultivars that are tolerant of colder temperatures. Rosemary is a low maintenance herb for gardens and containers – a great starter herb for new gardeners! Rosemary plants typically have bushy, upright growth but there are several cultivars that have a sprawling form and branches that cascade over the tops of stone walls or over the sides of pots and hanging baskets.
I clip the fragrant and flavorful leaves of my rosemary plants all summer long and then bring them indoors to overwinter in a sunny window or beneath a grow light. The needle-like leaves are packed with oils which give them their complex pine-like flavor. Rosemary is delicious on roasted potatoes and focaccia, and in meat dishes, casseroles, soups, and salads. In late spring or early summer the plants produce delicate flowers in shades of blue, purple, pink, or white. The pretty blooms attract bees, butterflies, and other pollinating and beneficial insects.
How to grow rosemary from seeds
Most gardeners buy rosemary plants, not seeds. This is because rosemary is a woody plant and growing it from seeds is a slow process. Plus the named varieties you buy from garden centres are grown from cuttings and not available in seed packets. If you want to try growing rosemary from seed, sow them at least 3 to 4 months before the last expected frost date. Also be mindful that rosemary seeds have a low germination rate with about 30% of them sprouting.
Fill pots or cell packs with a seed-starting growing mix and sprinkle the seeds on the surface of the soil. Don’t bury them, but instead lightly press them down so they have good contact with the growing medium. Place the containers under grow lights or in a sunny window. Rosemary seeds germinate best in warm soil (80 to 85 F or 27 to 30 C) and it’s beneficial to provide bottom heat with a heating mat. Germination may take 3 to 4 weeks so be patient.
Once the seeds have germinated, remove the heating mat. Maintain a lightly moist – not wet growing medium. Very wet potting mix can encourage damping off and other fungal issues. Leave the grow lights on for 16 hours a day. Again, because rosemary is slow to grow from seeds your plants may not be large enough to harvest from for many months. If you want rosemary in a hurry, buy transplants from your local garden centre.
How to grow rosemary from seedlings
Rosemary seedlings are available from nurseries and garden centres in spring and summer. Most are sold in 4 inch diameter pots, but you may luck into larger-sized plants as well. Look for healthy specimens that have bright green leaves and no yellowing or browning foliage. There are many varieties of rosemary available so read the variety descriptions carefully to select the one that best matches your growing conditions and needs.
Where to plant rosemary
Rosemary thrives in a site that offers direct sunlight and well-draining soil. Raised beds are perfect! You can grow rosemary in vegetable gardens or herb gardens or tuck plants in an ornamental garden like a rock garden, herb spiral or along the top of a rock wall. Avoid clay soil or areas where water doesn’t drain well. The plants grow best in sandy or sandy loam based soils. Personally, I think rosemary should be planted in a spot that makes it easy to enjoy the rich fragrance. I always plant rosemary on my sunny back deck so I can clip fresh sprigs as needed, but I also tuck a few plants in my raised beds too. It makes a terrific planting partner for other kitchen herbs like basil, oregano, thyme, and parsley.
Another consideration is when to plant rosemary. Don’t transplant rosemary seedlings into the garden until the last frost date has passed. Hard frost or freezing temperatures can damage or kill rosemary. Their ideal temperature range is 60 to 85 F (15 to 30 C). If the temperatures dip after you’ve planted rosemary outdoors, cover the plants with a row cover to protect them.
How to grow rosemary in containers
Rosemary is well suited to container cultivation and I love the classic combination of rosemary and terra cotta. Besides aesthetics, there are practical reasons to grow rosemary in clay or pottery containers. The heavy pots provide a strong base for rosemary plants, which can grow quite tall, especially if you’re clipping them into a topiary. Terra cotta also doesn’t absorb heat as quickly as metal or plastic pots and better regulates the temperature of the root zone.
That said, you can plant rosemary in any pot, planter, window box, hanging basket, bucket, or elevated herb garden. It does require excellent drainage, so be sure to select a pot with drainage holes. Rosemary plants can grow quite large and the pot should measure at least 12 inches across and 10 to 12 inches deep. As for the growing medium, I mix a high-quality, all-purpose potting mix with sand to boost drainage. A ratio of 70% potting mix and 30% sand is ideal.
How to grow rosemary
Rosemary is a fairly ‘hands-off’ herb and doesn’t require a lot of fussing. Regular watering and clipping are the primary tasks and I also fertilize the plants in spring with a slow release organic vegetable fertilizer. It’s important to know how to water rosemary, but it’s also essential to learn when to water rosemary. This herb is drought-tolerant and once garden plants are established, they don’t need to be watered unless there is a prolonged drought.
Potted rosemary plants, on the other hand, do need frequent watering. Rosemary is tolerant of dry soil, but the growing medium in the pot can’t be allowed to dry out completely. I check my container-grown rosemary plants by sticking a finger into the growing medium. If it’s dry an inch down, I water.
Rosemary is often grown indoors or overwintered inside. The plants appreciate high humidity and I spritz the pots of rosemary on my kitchen windowsill with a hand mister several times a week. Avoid placing indoor rosemary plants near a heat pump or other heat source that could dry them out. Although rosemary isn’t prone to many pest problems, aphids or spider mites aren’t uncommon. Use an insecticidal soap to manage pests.
How to harvest rosemary
Rosemary is a productive plant that yields plenty of flavorful leaves for cooking. Frequent harvesting encourages fresh growth and new shoots so don’t be shy about pruning rosemary plants. If you just need a little rosemary, you can pluck individual leaves. I prefer to clip sprigs from my plants using herb snips and try to cut back to a fresh set of side shoots. When harvesting consider the plant shape and remove branches that improve its structure. Dry surplus rosemary and store in jars.
How to overwinter rosemary
I garden in zone 5B/6 and know that my rosemary plants won’t survive a winter – even in my polytunnel! I dig my plants up and bring them indoors before the first killing frost. Potted plants also need to moved inside before the temperatures plummet. Place rosemary in a sunny window or beneath a grow light and mist the foliage several times a week. The following spring the plants can be moved back outside, but harden them off first. They need to be reacclimatized to outdoor growing conditions.
The best types of rosemary to grow
There are many forms of rosemary to choose from. Certain cultivars have upright growth and others pendulous branches. Plus, some are more cold hardy than others, so read variety descriptions carefully when selecting which rosemary plants to buy.
Rosemary ‘Arp’ (Zones 7 to 10)
‘Arp’ is a classic variety beloved for its cold tolerance. It’s hardy in zones 7 to 10, but when protected with a cold frame or insulating mulch often survives winters in zone 6. The plants have tidy, upright growth and in late spring produce bright blue flowers. ‘Arp’ can grow 3 feet tall and 3 wide. This is a great variety for culinary use.
Rosemary ‘Prostratus’ (Zones 8 to 10)
I’m a huge fan of this unique rosemary that has low, spreading growth. It’s also called ‘creeping rosemary’, and grows 2 to 3 feet wide and 10 to 12 inches tall. ‘Prostratus’ is stunning when planted along the top of a rock wall, in a rockery garden, or in a hanging basket. It has violet-blue flowers and bright green leaves with the standard rosemary flavor.
Rosemary ‘Hill Hardy’ (Zones 7 to 10)
As the name implies, this variety is reasonably hardy, overwintering in zones 7 to 10, and even zone 6 if protected. The compact, rounded plants grow 2 to 3 feet tall and wide. It’s perfect for pots or garden beds.
Rosemary ‘Foxtail’ (Zones 8 to 10)
This incredibly ornamental rosemary is one of my favorites! It has an eye-catching mounding form with branches that arch attractively over the sides of pots and planters. It also looks fantastic planted in raised garden beds. ‘Foxtail’ has bright purple-blue flowers and an intense rosemary flavor.
Rosemary ‘Barbeque’ (Zones 8 to 10)
‘Barbeque’ rosemary is ready for the grill! The name comes from the plant form – upright with long, straight branches. Clip the stems to make sturdy skewers for grilling meats, vegetables and even fruits like pineapple. The homegrown skewers infuse your food with the fragrance and flavor of rosemary.
Rosemary ‘Rex’ (Zones 8 to 10)
‘Rex’ is a popular variety that is reliable, flavorful, and vigorous. The plants offer upright growth and deep green, needle-like leaves. In zones 8 to 10 the plants can grow up to four feet tall. Plant it in garden beds or pots, or train it into a topiary. The dense growth responds well to clipping if you wish to clip it into a cone or sphere shape.
Rosemary ‘Tuscan Blue’ (Zones 8 to 10)
With its quick growth and upright form, ’Tuscan Blue’ is also a good choice for topiaries. Or, let it grow and enjoy the natural form. As the name hints, ‘Tuscan Blue’ has flowers that are are deep violet-blue in color. In warm climates, this variety can grow 7 feet tall and makes an eye-catching fragrant hedge or privacy screen.
For more information on growing herbs, be sure to check out these in-depth articles:
- How to DIY and plant an herb spiral
- How and when to harvest homegrown herbs
- Growing a culinary herb garden
- Learn how to grow herbs indoors
Were you wondering how to grow rosemary?