The Gardeners Almanac

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Coleus

Common name: Flaming Nettle

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Week Numbers

Black Spot

Compost

Fertiliser

Heating

House plants

Pricking out

Red spider mite

Seed sowing

Tip cuttings

Watering

Whitefly

Overview:

Coleus is grown mainly for its ornamental foliage and is best suited for cultivation in the greenhouse or the home.

If being grown in containers in milder areas of the UK, it can be situated outdoors during the summer then brought back indoors before the onset of frost.

Alternatively, treat them as a bedding plant in a flower border.


Panicles of blue flowers

Plant in Flower

Blends of red and purple covered leaves with green serrated edges

Collection of various colours

They can grow to a height of 500mm (18") with a similar spread.


The nettle-like leaves, hence the common name flaming nettle come in various shades and blends of green, yellow, red and maroon.

The small blue and white tubular flowers should be pinched out before they develop, pinch them out the buds as soon as they are large enough to handle.

Drought and starvation will encourage the flower production, so water and feed the plants weekly with liquid manure from June to September.


Collection of different leaf colours and markings.

Crimson leaf with red veining and green serrated edges

Crimson leaf with red veining and green serrated edges

Purple & Crimson with wide green serrated edges

Purple & Crimson with green serrated edges


To prevent leaf scorch provide some shade in very hot, bright weather.


Too much sun can also bleach the colour from the leaves.


To get a bushy plant, pinch out the growing tip at fourth or fifth pair of leaves and stop side-shoots at second or third leaf pair.

Non flowering side-shoots make the ideal cuttings.

Train young coleus into standards by removing all side-shoots until desired height is reached.


Keep an eye open for signs of pests and diseases.

Provide a winter temperature of 13°C (55°F)


Cultivation:
Week 14:

Sow seeds in pots / trays of seed compost and place in a propagator set to hold 18°- 21°C (64°-70°F).

Germination should take about 7- 10 days.


Week 18:

Prick out seedlings (if large enough to handle) into 50mm (2") pots of potting compost,

Pot on at 4-5 weeks intervals until they are in their final 150-200mm (6"-8") pots.


Week 23:

Take tip cuttings.

Select healthy tips of non flowering stems, and trim to just below a leaf joint to leave a cutting of about 70-100mm (3”-4”) long.

Insert round the rim of a pot filled with a well-drained compost.

Place in a propagator or a clear plastic bag and maintain a temperature of 18°C (65°F).

Once rooted, pot up the cuttings into 50mm (2") pots of potting compost.

Approx every three to four weeks later (circa Week 26/27), pot on until they are in their final 150-200mm (6"-8") pots.