How to grow dierama

What are dieramas?

These South African plants are also known as angel’s fishing rods, as their bell-like flowers hang from slender, arching stems.
 
The flowers come in many shades of pink – from bright magenta to pale rose – as well as dusky purple and white, depending on the cultivar. These rise above clumps of long grass-like evergreen leaves.
 
Growing from bulb-like corms, these perennial plants last for many years when given the right growing conditions. Most of the widely available species are fairly hardy, but need a warm, sheltered spot.
 

How and what to buy

Dieramas are usually sold in containers, and are available from most large garden centres, specialist perennial nurseries and online suppliers.
 

Where to get ideas and advice

 
Go to RHS Find a Plant and search for ‘dierama’ to browse photos and plant descriptions, and find out where to buy them.
 
Browse online suppliers, who may offer a wider range of dieramas than small garden centres.
 

Dieramas are easy to plant, but take care to get the positioning correct, to ensure they thrive. They need plenty of warmth and free-draining soil, so avoid cold, shady or soggy conditions.
 

Where to plant

Choose an open, sunny position in fertile, moist but well-drained soil that doesn’t dry out in summer or become waterlogged in winter.

If you have heavy clay soil or light sandy soil, dig in plenty of well-rotted organic matter before planting. Alternatively, grow them in raised beds containing suitably fertile soil or compost.

See our guide to identifying your soil type. 

Most of the widely available species are fairly hardy, but avoid planting in frost-prone locations. Check plant labels for details before buying. Dieramas generally grow best in the ground, but they can also be planted in containers. This makes it easier to bring them indoors over winter if necessary.

Give dieramas plenty of space, so their long, elegantly arching stems can be displayed to full effect. Clumps can grow to about 150cm (5ft) tall and 50cm (20in) wide.

When to plant

Containerised plants are available to buy all year round, but are best planted in spring. Avoid planting in hot, dry or cold weather.
 
If planting the corms, do this in spring, setting them 5–7.5cm (2–3in) deep.

How to plant

When planting in the ground, position the dierama in the planting hole so the top of its compost is level with the surrounding soil. See our guide to planting perennials. 

When planting into a container, choose a fertile, well-drained potting compost, such as John Innes No 2. See our guide to planting in containers. 

Once new plants are settled in, dieramas need little additional care.
 

Watering

Water newly planted dieramas regularly for their first growing season. After that, they shouldn’t need extra watering except during dry summers.
 
Plants in containers can dry out quickly, so should be watered regularly throughout the summer.

Feeding

Established, healthy dieramas growing in fertile soil don’t generally need feeding. But if growth or flowering is poor, or plants are in containers, apply a general purpose fertiliser, such as blood, fish and bone or Growmore, in spring.

Mulching

Add a mulch of well-rotted garden compost annually in autumn or spring. This helps to prevent the soil drying out and will boost levels of beneficial organic matter in the soil, as worms will gradually take it down into the ground. Learn more in our guide to mulching.
 

Overwintering

Many dieramas are not reliably hardy, especially in colder parts of the country. To be on the safe side, give them some protection over winter, especially until they are well established. You can cover plants with a cloche or fleece and lay a thick layer of mulch over the root zone.  See our guide to protecting plants over winter.

No real pruning is needed, although you can cut out any old, faded foliage in spring to keep plants looking tidy.

You can grow more plants for free by sowing seeds and dividing established clumps.

Sowing seeds

• Collect ripe seeds from your plant after flowering, in late summer or early autumn.

• Sow the seeds straight away into small pots or seedtrays of John Innes or other seed compost and place in a coldframe to germinate.

• Prick out the seedlings after a few months, and grow on singly in a frost-free place, such as a greenhouse.

• Plant out the following spring.

• Flowering often takes five years from seed.

• Plants grown from seed may vary slightly from the parent plant if there are different cultivars growing nearby.

Dividing clumps

You can divide established clumps of dierama, but only do this occasionally as they may be slow to re-establish afterwards. The resulting plants will be identical to the parent. Dierama grow from corms that build up year by year into chains, similar to crocosmias.

• Lift the large clump carefully, taking care not to damage the brittle, fleshy roots.
• Gently pull apart into several smaller clumps.
• Cut the foliage down by half with secateurs, to reduce water loss.
• Replant the smaller clumps straight away, setting them at the same level they were growing previously. They will take one to two years to flower freely again.

Dieramas are relatively trouble-free, as long as their growing conditions are correct. However:

• Young plants and clumps that have been divided and replanted are slow to establish. They resent disturbance, so try to get the positioning right first time. 

• Dieramas cross-pollinate easily, so many plants sold as Dierama pulcherimum are actually hybrids, although still very attractive plants.

• Aphids may occasionally be a problem.