Rosmarinus officinalis
( rose - MAYR - inn - uss off - fish - inn - AL - uss )
At-A-Glance InformationCommonly called Rosemary (and now known under the botanical name Salvia rosmarinus), this species of evergreen shrubs needs full sun and little to moderate water. The flowers will attract bees, hummingbirds and butterflies to your garden. These aromatic, Mediterranean shrubs are popular in gardens, and have varying heights and habits, as well as flower colors. Flowers can bloom in blue, pink, or white and appear from winter through springtime. The flowers and foliage are edible, and make tasty additions to salads, honeys, and seasoning blends.
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Rosmarinus officinalis Varietals
The previous genus Rosmarinus was in the plant family Lamiaceae, and its species were recently (in 2017) placed in the genus Salvia, based on taxonomic evidence. 'Rosmarinus' means "dew of the sea", referring to this shrub's preferred natural habitat in oceanside plantings. The best growing zones for Rosemary are 4-24, H1 and H2. To find your zone, click here: Zone Map.
'Albiflorus' ('Albus')
This variety has a semi-upright habit, to 6 feet tall and wide. Flowers are white veined with pale lavender. Hardy to 0 degrees Fahrenheit. |
'Arp'
To 4 feet tall and just as wide. This is the hardiest variety; good down to -10 degrees Fahrenheit. Native to Arp, Texas. Foliage is dark green with a grey tint, and flowers are bright medium blue. |
'Barbecue'
5 feet tall and 2-3 feet wide, with a great fragrance for cooking. Flowers are blue. |
'Benenden Blue'
('Pine-Scented Rosemary) This variety of Rosemary reaches 3 feet tall and 4 feet wide (or more) with leaves that have a strong pine fragrance. Flowers are light blue. Bitter flavor. Tender. |
'Blue Spires'
Vertical growth to 5-6 feet tall and just as wide or wider (at maturity). Flowers are deep blue. Great landscape variety; can be sheared into a dense hedge. Great for seasoning dishes. |
'Collingwood Ingram'
('Ingramii', 'Rex #4) 2-2.5 feet tall and 4 feet wide (or more), upright habit with gracefully curving branches. Deep blue flowers with violet veining. Good for bank or groundcover purposes, but not good for seasoning. |
'Corsican Prostrate'
Arching spreading habit to 1.5 feet tall with blue flowers. Tender variety. |
'Golden Rain' ('Joyce DeBaggio')
Bushy, upright grower to 2-3 feet tall and just as wide. Green leaves have golden edges, though variegation fades in summertime. Deep purple-blue flowers. |
'Hill Hardy'
Compact, bushy growth to 5 feet tall and just as wide. Foliage is stiff. Flowers are light blue and will make a repeat bloom in autumn. Light fragrance; hardy to 0 degrees Fahrenheit. |
'Huntington Carpet' ('Huntington Blue')
This variety reaches 1.5 feet tall and spreads quickly. Center remains dense. Flowers are pale blue; best for groundcover or banksides. |
'Irene'
Reaches 1-1.5 feet tall and spreads at a rate of 2-3 feet per year. Flowers are deep lavender-blue, cold-hardy. |
'Ken Taylor'
2.5 feet tall and 4 feet wide or more, with dee blue flowers and a trailing habit. Tender. |
'Lockwood de Forest'('Santa Barbara', 'Lockwoodii', 'Forestii')
Similar to 'Prostratus', but mounds to 2.5 feet or taller with lighter green foliage and bluer flowers. |
'Majorca Pink'
This variety reaches 2-4 feet tall and 2 feet wide, with a twisting, picturesque shape, eventually flopping over to spread 3-4 feet wide. Lilac-pink flowers; fruity fragrance. |
'Prostratus'
2 feet tall and 4-8 feet wide; Trails over walls or edges. Flowers are pale lavender-blue and bloom in waves from fall through spring. Mounds up and turns woody with age, forms a bare center. Great for hanging pots; tender. |
'Spice Islands'
Upright to 6-8 feet tall; good for screening or backgrounds. Large blue flowers, good for fragrance and seasoning. |
'Tuscan Blue'
Brought over to England from Tuscany, this variety has broader leaves, deep blue flowers and an upright habit. Reaches 6-7 feet tall and 1.5-2 feet wide. With age, turns woody and bare at the base. |
Caring for and pruning Rosmarinus officinalis shrubs
Plant these shrubs in full sun (in a spot that gets at least 6-8 hours of sun per day), south-facing areas are great for Rosemary plants. Ensure that soil is well-draining, and if your soil is clay or heavy, make sure to amend it with plenty of organic material prior to planting your shrub. Rosemary performs well in seaside and inland conditions, even with hot sun and poor, alkaline soil (if given infrequent light feedings of fertilizer and moderate waterings). Fertilize sparingly, about once a month during the growing season (spring through early fall). Avoid high-nitrogen fertilizers. Too much fertilizer or water can result in woodiness. Growth can be controlled through tip pinching when plants are smaller. On larger plants, prune frequently but lightly. Plants can become woody and bare in the center; in these cases, simply cut back a few selected branches toward the center of the plant by about half (make sure your cuts are done in areas that are actively leafing; bare wood sections will not sprout new growth). Branches root where they touch the ground, and creeping varieties will spread indefinitely. Upright varieties tend to be more cold-hardy, and prostrate ones tend to be more sensitive to cold. Rosemary can also be grown in containers.
Propagation
Rosemary can be propagated either by using cuttings or from seed. To ensure that your propagated plant will have the exact same qualities and characteristics as the parent plant, use the cutting method. If you would like to experiment and see what plant you can grow from seed, just keep in mind that it will not necessarily be the same as the parent plant. To propagate your shrub, follow the instructions below:
Propagating Rosmary by Cutting
Propagating Rosemary by Division
This type of propagation is relatively simple; you will need a clean shovel, mulch, fresh soil (any kind will do, though it does need to be well-draining), compost, and pots (12 inch pots will do, and these are only necessary if you will be saving divided plants for transporting elsewhere). Division is best done in spring or fall (after the plant has entered dormancy and been cut to the ground, but before it has begun its new spring growth), and needs to be done every four to five years regardless of whether you have the goal of propagating the plants for best performance. To propagate by division, follow these steps:
Propagating Rosmary by Cutting
- Gather your materials. You'll need a clean, sanitized, sharp pair of garden shears, rooting hormone, a pencil, and a 3-inch pot filled with well-draining compost or other organic material. If you don't have any potting medium on hand, you can make some. Just mix together equal parts (by volume) moss peat and horticultural-grade sand or grit sand.
- In spring or early summertime, choose the plant that you'd like to propagate. Ensure that this plant has had a good watering the night before, as this will improve the chances your cutting will take root. Cut one or more 6 inch portion(s) of the end of a non-blooming branch and strip the leaves off of the lower half. Make a hole in your planting medium by pushing your pencil into the soil. Dip the end of the stem in rooting hormone, and plant it in your pot. Fill in soil around the cutting to support it, but do not pack it down too much.
- Moisten with water, and ensure that the pot has good drainage. Your pot should be kept in warm, sunny conditions indoors (and not in direct sunlight). Water whenever your soil is dry under the top layer. After about four to six weeks have passed, your cutting should be rooted. When you notice new growth, you'll know you have roots.
- Keep your new plant in an area with bright light (though not direct sunlight) and temperatures between 55 and 70 degrees Fahrenheit. Ensure that the soil stays moist, but not wet, until the next spring, when you can transplant it to its new home. Ensure that the last frost of the year has occurred before doing this, as it can seriously damage your new shrub.
Propagating Rosemary by Division
This type of propagation is relatively simple; you will need a clean shovel, mulch, fresh soil (any kind will do, though it does need to be well-draining), compost, and pots (12 inch pots will do, and these are only necessary if you will be saving divided plants for transporting elsewhere). Division is best done in spring or fall (after the plant has entered dormancy and been cut to the ground, but before it has begun its new spring growth), and needs to be done every four to five years regardless of whether you have the goal of propagating the plants for best performance. To propagate by division, follow these steps:
- Gather your materials. Using a shovel, dig up your existing plant. Start from the outside and work your way in to avoid damaging the tuber roots. Once you have worked it up out of the ground, lay it out.
- Start to tease apart the roots with your gloved fingers. Once the roots are untangled, separate your plant into segments, ensuring that each one has at least one thick tuberous section.
- Prepare your pot(s) or new planting site(s) with amended, well-draining soil. You can either bring in new soil or simply amend your existing soil with compost to complete this task. Then, plant your divided plants and water thoroughly.
- Apply a thick layer of mulch over the new planting to protect it from cold weather as it acclimates to its new home. Then, enjoy watching it sprout.
Problems and Pests
Rosemary plants rarely have pest or disease issues, but can be susceptible to the following problems:
- Spider Mites
- Aphids
Gallery
Videos
How to use Rosemary.
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Rosemary is an easy herb to grow.
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Tips and tricks for growing Rosemary.
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How to grow Rosemary shrubs using cuttings.
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Resources
The New Sunset Western Garden Book: The Ultimate Gardening Guide (2012) - Pages 578 - 579, Rosmarinus officinalis (Rosemary)
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