How to grow coleus

Coleus plants, also known as solenostemon, plectranthus or painted nettle plants, are grown for their velvety foliage that comes in combinations of bright red, burgundy, yellows, green, pink, brown and bronze.

Coleus look good in summer bedding schemes or as a filler at the front of a summer border, and are ideal for summer pots and containers. They’re perfect for an exotic or jungle-style planting scheme. They can also be grown as house plants or in a conservatory.

Coleus is actually an ornamental member of the mint family, native to Indonesia. All species formerly in the Coleus genus have now been split into either Plectranthus or Solenostemon. 

How to grow coleus

Grow coleus in a sunny or partially shaded spot to bring out their beautiful leaf colours. They do best in moist but well drained soil. Coleus plants are tender perennials, which means they won’t survive in cold weather. They are usually grown as annuals in the UK, planted out in May when there is no threat of frost. To keep plants from year to year, bring them indoors in autumn, or take cuttings in summer that can be grown on for new plants the following spring.

Where to plant coleus

[image id=”53860″ size=”landscape_thumbnail” title=”Planting coleus in the border. Paul Debois” alt=”Planting coleus in the border. Paul Debois” classes=””] Planting coleus in the border. Paul Debois

Plant coleus in a sunny or partly shaded spot, in moist but well-drained soil. Coleus are low growing, so they look best at the front of a border, combined with other bedding plants, or in pot on a patio. If you’re growing coleus as a house plant, grow it in a bright spot that gets a little direct sun.

How to grow coleus from seeds

For outdoor plants: sow January to May
For house plants: sow year round

1. Fill a tray with seed compost.
2. Sprinkle the seeds on top – they need to be surface sown.
3. Place a lid or polythene bag over the tray until the seeds germinate. The ideal temperature for germination is 20-25ºC. Germination can take 7-21 days.
4. When seedlings have true leaves, prick them out and transfer to a small pot, around 7.5cm.

How to plant coleus

[image id=”53865″ size=”landscape_thumbnail” title=”Planting coleus with lantana and impatiens. Jason Ingram” alt=”Planting coleus with lantana and impatiens. Jason Ingram” classes=””] Planting coleus with lantana and impatiens. Jason Ingram

You can buy coleus as ‘plug plants’ (young plants) in early spring. Grow them on indoors until the weather warms up. Plant them out in the garden in May, once there are no more frosts forecast. Harden them off (acclimatise them to outdoor conditions) for a week beforehand.

Prepare the soil by forking in some peat-free, multi-purpose compost. Dig a hole that is slightly larger than the original pot, add the plant and fill around it with soil. Water in well.

If planting in a pot, dig a hole that is the same size and depth as the original pot, and plant at the same level. Water in well.

Caring for coleus

[image id=”53859″ size=”landscape_thumbnail” title=”Frost damage. Tim Sandall” alt=”Frost damage. Tim Sandall” classes=””] Frost damage. Tim Sandall

Outdoors:

• Once planted, pinch out the growing tip (central stem) to encourage a bushier plant.
• Coleus that is grown in soil which is rich in nutrients won’t require feeding. Feed coleus in pots after six weeks, when the nutrients in compost have run low.
• Water bedding plants in containers regularly, especially during hot weather. During hot spells water coleus growing in borders.
• If you’re growing coleus in pots outdoors, move them indoors in autumn before the first frosts. They won’t survive in temperatures below 10ºC. If you’re growing them as bedding plants in the ground, you could take cuttings in summer to ensure some plants for next year.

Indoors: 

• Feed coleus house plants with a high nitrogen fertiliser every two weeks through the growing season
• Water when the top third of the compost is dry
• Place in a spot that gets bright, indirect light. Plants won’t thrive in shady locations.
• Coleus do best in rooms with average humidity so no misting is necessary. The best temperature is between 15-24ºC.

How to prune coleus

Outdoors: It’s not necessary to prune coleus but pinching out the shoot tips will encourage bushiness. This will also help keep plants neat and compact.

Indoors: remove yellowing or dead leaves.

How to propagate coleus

[image id=”53864″ size=”landscape_thumbnail” title=”Taking coleus cuttings. Sarah Cuttle” alt=”Taking coleus cuttings. Sarah Cuttle” classes=””] Taking coleus cuttings. Sarah Cuttle

Coleus plants are easy to propagate. Take cuttings in summer to increase your supply of plants, then grow them on for next season in a greenhouse or conservatory.

Growing coleus: problem solving

Coleus has no problem with diseases if grown outside, but if grown in a conservatory or indoors, look out for pests such as whitefly, mealybugs and scale insects.

Coleus varieties to try

Coleus scutellarioides ‘Chocolate Mint’ – velvety, maroon leaves, edged with bright green make this a dramatic foliage plant for annual planting schemes. The pale blue flowers are insignificant and can appear at any time of year. Height x Spread: 35cm x 30cm

• Buy Coleus ‘Chocolate Mint’ from Gardening Express
• Buy Coleus ‘Chocolate Mint’ seeds from Nicky’s Nursery

Coleus scutellarioides ‘Trusty Rusty’ – a vibrant variety with semi-succulent stems and velvety, rust-colored leaves with a serrated, golden outer edge. H x S: 35cm x 30cm

• Buy Coleus ‘Trusty Rusty’ from J. Parker’s

Coleus ‘Saturn’ – the leaves of this variety are a brown to burgundy shade with a bright lime splash of colour in the centre. Ideal for pots and bedding schemes. H x S: 50cm x 30cm

• Buy Coleus ‘Saturn’ from Dibley’s

Coleus scutellarioides ‘Black Dragon’ is a striking variety for pots or as a bedding plant in borders, with frilly dark purple leaves that have a pink centre. H x S: 35cm x 30cm

• Buy Coleus ‘Black Dragon’ from Marshalls Garden

Coleus ‘Skeletal’ will make a focal point in any bedding display, with its bright pink, fishbone-shaped leaves. These are rimmed in lime green. H x S: 35cm x 35cm

• Buy Coleus ‘Skeletal’ from Thompson & Morgan

Coleus caninus is known as the scaredy cat plant or scat plant – it’s foliage smells and is said to repel cats. Plant it in your border to see if you can ward off unwanted visitors. H x S: 40cm x 40cm

• Buy Coleus caninus from Thompson & Morgan

Frequently asked questions

Are coleus hardy in the UK?

No, coleus are not hardy. These tender plants can be grown either as bedding plants to add colour to beds and containers through the summer, or as house plants indoors.

What are the disadvantages of coleus?

The downside of coleus is that it’s a tender plant so it won’t survive outdoors over winter. If you want to enjoy coleus all year round, grow it as a house plant.