The Gardeners Almanac

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My Back Garden

Anchusa

Common name: Alkanet

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Week Numbers

Alpines

Coldframe

Compost

Containers

Frost

Gravel

Planting out

Pricking out

Root cuttings

Seed sowing

Watering

Overview

There are a number of different species of Anchusa, each with its own particular needs.

Depending upon the species they can be used in the borders, rockeries or alpine house e.g. caespitose; is generally used in rockeries or alpine houses, capensis an annual / biennial for the border.

caespitosa; grows to a height of 50-70mm (2”-3”) and spreads to around 225mm (9”)

Named variety

Anchusa - Blue Angel

Darkblue flowers with white centre

Anchusa caespitosa

Pale blue forget me not type flowers

Anchusa capensis

Anchusa is a short lived perennial that bears rosettes of deep green musk scented bristly leaves.

The deep blue flowers with a white eye are attractive to bees and appear in dense clusters in the centre of the rosettes from May to July.


Some species can be difficult to grow outdoors in the UK, however, given the right drainage conditions they may last for a few years, e.g. on a raised gravel topped bed, or in a sunny location.

Ideally they should be grown in pots in an alpine house.


Cultivation
Week 8:

Take root cuttings by scraping away soil to expose suitable lengths of main root.

Cut off pencil-thick pieces with either a sharp knife or secateurs.

Cut the pieces into 50mm (2”) sections by making a sloping cut at the base and a straight one at the top, this ensures they are planted the right way up.

Push each section down vertically into the compost with the sloping cut facing down.

Then cover the tops with compost or 13mm (½”) of sharp sand.

Keep containers moist and frost free.

When four or five leaves are showing, set the plants in 75mm (3”) pots of John Innes potting compost No.1 (or equivalent)


Week 12:

Sow seed in pots/trays of seed compost.

Seed usually germinates in 1-4 weeks at 21°c(70°F)

Prick them out when they are large enough to handle into 75mm (3”) pots and grow on till planting out time.


Week 25:

Sow seed in-situ in a nursery bed.

Prick them out when they are large enough to handle into 75mm (3”) pots and grow on till planting out time.


Week 36:

Plant out 150-200mm (6"-8") apart in a well drained gravel/scree covered bed that is free draining.

Protect plants with cloches through the worst of the winter weather.

Alternatively; store in a cold frame and plant out in Week 17 the following year if conditions allow.


If the intention is to grow them in containers then pot on as necessary to prevent them becoming ‘pot-bound’


capensis; Is a biennial species with a bushy habit and is usually grown as an annual.

It grows to a height of 500mm (18”) and spreads to around 225mm (9”)

The mid-green narrow pointed leaves are quite hairy.

The blue flowers are produced in long panicles from July to August.

This species is suitable for growing in containers, or any well-cultivated soil in a sunny position where they will produce sprays of forget-me-not like flowers (to which it is related) throughout the summer.


Week 40:

Plant out 150-200mm (6"-8") apart in a well drained gravel / scree covered bed that is free draining.