The Gardeners Almanac

The place to find out what to do in the garden this week
My Back Garden

Rosemarinus officinalis

Common name: Rosemary

Related Links

Week Numbers

Coldframe

Compost

Containers

Frost

Growbags

Heel Cuttings

Layering

Mini garden

Planting out

Plug plants

Seed sowing-indoors

Seed sowing -outdoors

Watering

Overview:

Rosemary in Flower

A free flowering bushy evergreen shrub, that is highly attractive to bees.

The leaves are strongly aromatic and may be used, fresh or dried, for flavouring.


This herb has been used in food and medicine preparations for centuries.

Being an evergreen plant, the leaves are available at all times.

There are numerous varieties but not all are suitable for cooking.


The most common variety is officinalis or Common Rosemary, which can grow to a height of 900-1200mm (3-4ft) high.

The small, blue or white flowers open in March / April and continue to appear sporadically until September.

It may require staking in more exposed areas.


This plant originates from the Mediterranean so it requires full sunlight, and good drainage.

It won’t tolerate the cold wet winters of the UK so it is recommended that it be grown in containers and these containers moved to a frost free position in the winter months.

It thrives on low fertile soils and will tolerate very dry conditions, once established.


Cultivation

Week 17:

Sow seed in trays or modules containing a proprietary seed compost and place in a cold frame to germinate.

Germination can be slow and erratic.

Later sowings can be made directly in to a seed bed in very shallow drills.

When seedlings are large enough to handle they should be transplanted into to pots until planting out time.


Rosemary is not easy to grow from seed so buying small plants from the garden centre might be a better option.

If pre-germinated plants have been obtained by mail order, unpack immediately on arrival and water thoroughly, and if necessary place in a sheltered, airy position out of direct sunlight for a few days so the plants can acclimatise.

Once acclimatised either plant them direct into the garden, or into containers, growbags, or if kept trimmed they can be grown in pots on the windowsill.


Week 18:

Layer suitable woody stems by burying the stem.

Firstly remove leaves from the stem to be buried and scrape the underside to create a wound then loosen the soil and pin the stem down with wire.

Cover with soil, leaving the growing tip clear of the surface; water well.

New plants should be ready to detach by autumn.


Week 21:

Plant out the young plants 900-1200mm (3-4ft) apart in any ordinary, well drained garden soil, in a sunny position.

Ensure that soil does not waterlog, especially during winter.


Week 25:

Mature plants that have become straggly, can be regenerated by taking heel cuttings.

To take heel cuttings select a non-flowering shoots, remove the lower leaves, dip the cuttings into hormone rooting powder and insert them into pots containing a 50-50 mix (by volume) of compost and sharp sand.

Place in a propagator, or pull a plastic bag loosely over the cutting to retain moisture, seal it and place on a warm windowsill (not in full sun).

Roots should form in six weeks.

Pot or or plant out into free-draining soil.


Circa Week 28-30:

Copper coloured Beetle

Rosemary Beetle

Keep a look out for the Rosemary Beetle.

Although the adult beetle does not do much damage., but its larvae can!

Around this time the adults mate and lay the eggs then 10-14 days later the larvae hatch.

A sign that the grubs have been feeding is when you see discoloured foliage with dried up edges.


There are chemicals available to control these pests, however if you are only growing a few plants the best option is just to lift off the larvae manually and destroy them.

When fully fed, the larvae go into the soil to pupate, and appear as beetles the following year.