Favourite Herbs: Rosemary

Rosemary

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Rosmarinus officinalis

Tender evergreen perennial; grown as an annual in most areas of Canada

Height 30 to 100 cm, can reach 200 cm; spread 30 to 60 cm.

Looks like a little tree: upright bush growth habit, with hundreds of straight, needle-shaped, succulent green leaves; the branches sometimes twist. Creeping varieties have a prostrate growth habit.

Fragrant blue flowers appear in summer.

Try these!

Rosmarinus officinalis ‘Arp’: Hardier strain, survives outdoors in zone 6 with winter protection

Rosmarinus officinalis 'Prostratus' (creeping rosemary): Produces lots of pale-blue flowers; fine creeping/trailing growing habit

Rosmarinus officinalis ‘Rex’: Very upright variety with large, deep-green leaves; vigorous growth habit.

Planting

Rosemary can be difficult to grow from seed. If you enjoy a challenge, start indoors from seed in February or early March; otherwise, grow young plants purchased from a garden centre or propagate from cuttings.

How much: At least two plants.

When: Around the date of average last spring frost.

Where: Full sun; tolerates light shade. Excellent in containers. Prefers light, well-drained, dry soils. Space plants 45 to 60 cm apart in the garden; space one plant per pot in a small container, 3 to 5 plants per pot in a large container.

Care and Nurture

Once established, rosemary is easy to grow! Young plants need lots of water, but once established, rosemary is very drought resistant and can tolerate a dry spell or two. Rosemary loves the heat!

Harvesting

If you bring your rosemary inside for the winter and put it in a sunny window, you can continue to enjoy fresh leaves year-round. Harvest lightly during the winter, however, because the plant is getting less light and producing fewer leaves.

For best flavour: Harvest leaves just before the flowers bloom.

Leaves: Harvest throughout the growing season. Cut sprigs and use whole, or strip the needles and discard the stem or use on BBQ  for flavour.

Flowers: Harvest as they open. Clip cleanly from the stem. Remove any green bits before eating.

Preserving the Harvest

Rosemary leaves are best preserved by drying (see page XXX). The flowers can be used fresh or preserved in oil.

Tips

  • Two other rosemary varieties you might enjoy are Rosmarinus officinalis 'Benenden Blue', which has deep-blue flowers, narrow leaves, and an upright growth habit, and Rosmarinus officinalis ‘Blue Boy’, which produces lots of flowers, has excellent flavour, and has a more compact form. Blue Boy is a good choice for growing indoors in small pots.
  • If rosemary is hardy in your area, remember that it’s a short-lived perennial. After a few years it will become bare, sparse, and woody. I like to replace my plant every 3 years. Never cut it back in the fall: the growth above the ground will help protect and insulate the roots over the winter.
  • It's best to grow rosemary in large pots, since most Canadians will need to bring it indoors for it to survive the winter.
  • Rosemary’s narrow leaves don’t normally display signs of wilt, even when the plants get quite dry, so if your plant is wilting, it hasn’t been watered in a very long time.

To Note:

  • In England, rosemary is a traditional Yuletide green and serves as a Christmas tree when decorated with ornaments. Recently one American herb grower began raising rosemary shrubs large enough to use as Christmas trees. They take 2 years to grow and sell for about $300 US. In a similar vein, we bring in rosemary topiaries in clay pots each winter. People love having a beautiful, scented plant like rosemary around for the holidays.
  • Rosemary can be easily trained to grow in wreath or topiary form.
  • Rosemary is native to the Mediterranean region and is commonly found growing close to the ocean—hence the common name “rose of the sea” (rosa del mare).
  • Rosemary is an ingredient in many soaps, shampoos, and insect repellents. One kilogram of oil is obtained from 200 kilograms of flowering rosemary stems.
  • Branches or sachets of rosemary are often placed in clothes closets to keep moths away.
  • Rosemary flowers are attractive to bees.
  • In ancient times, rosemary was used in place of expensive incense. An old French name for it was "Incensier.”
  • During World War Two, a mixture of rosemary leaves and juniper berries was burned in French hospitals to kill germs. Later research showed that rosemary oil does indeed have some antibacterial effect.
  • Rosemary was carried at religious ceremonies. It was believed that its pungent scent would ward off disease and evil spirits. Brides wore wreaths of rosemary to denote love and loyalty, and branches gilded and tied with ribbons was presented to guests.
  • In medieval times, rosemary was believed to grow only in the gardens of the righteous, and was used as a charm against witchcraft—particularly the Evil Eye.