How to grow strelitzia

What are strelitzias?

Also known as bird of paradise, these are South African plants with spectacular flowers and large paddle-shaped evergreen leaves. They are tender, so need to be grown indoors in the UK, in a conservatory or large bright room, where they’ll make a big tropical centrepiece. They can grow to at least 1.5m (5ft) tall and 1m (3¼ft) wide over time. Plants can also be moved outside over the summer to give a tropical boost to a warm, sheltered patio.

There are several species, but Strelitzia reginaeis the most popular for growing as a houseplant. It produces flamboyant orange and blue flowers in winter and spring, which stand tall above the foliage, and each one lasts up to a month. Plants usually need to be a substantial size, and five to ten years old, before they flower.

Choosing strelitzias

Strelitzia reginae is the most widely available species. With big paddle-shaped leaves on long stiff stalks, and spectacular orange and blue flowers, it will grow into a large plant 1.5m (5ft) tall or more, and well over 1m (3¼ft) wide. So make sure you have plenty of space to display this large, spectacular plant to full advantage. The cultivar

Gardeners often use the word variety when referring to a specific plant, but the correct botanical term is 'cultivar'. Whichever word you use, it means a distinctive plant or plants, given a specific cultivar name and usually bred to enhance certain characteristics, such as flower or fruit size, colour, flavour or fragrance, plant size, hardiness, disease resistance, etc. Additionally, it is worth knowing that, botanically, variety has another meaning - it refers to a naturally-occurring distinct plant that only has slight differences in its looks. For example, Malva alcea var. fastigiata differs from typical plants by having an upright habit.

‘Kirstenbosch Gold’ produces yellow and purple flowers.

Other species may also be available from tropical plant retailers. Strelitzia nicolai produces blue and white flowers, but grows up to 10m (33ft) tall eventually, so is too big for most homes in the long term.

Buying strelitzias

Strelitzias can be bought as plants or seeds:

• Plants are available from houseplant and tropical plant suppliers, as well as from larger garden centres. They’re sold in a range of sizes, depending on their age. Buying plants that are already in flower can save a potentially long wait, but they can be quite expensive
• Seeds are available in garden centres and online. Germination
  

  Germination is the process by which a seed develops into a new plant. It starts with the seed coat absorbing water, expanding and splitting, which allows oxygen and water into the seed so its food reserves can be broken down and used by the embryo for growth. The first root (called the radicle) pushes into the soil to anchor the new plant in place and start absorbing water and nutrients. The first shoot (called the plumule) then grows upwards, out of the soil, towards the light.

  can be slow, and plants then usually take five or more years to reach flowering size. But it’s very rewarding when your own seed-raised plant eventually blooms!

Buying: garden centre plants

Buying: mail order plants

How to choose healthy plants

Newly bought strelitzias won’t usually need repotting for a year or two, and keeping these plants slightly pot-bound

Describes a pot-grown plant whose roots are filling the container, densely packed and intertwined. Check the roots of container plants regularly, and re-pot into a larger container before they become pot-bound, to ensure continued healthy growth. The roots of pot-bound plants are unlikely to spread out into new soil or compost without first being physically loosened.

tends to encourage flowering. But once the roots have filled the original container, it’s time to repot. This is best done every couple of years in spring, after flowering. Choose a pot that is only slightly larger and use peat-free loam-based compost

Can refer to either home-made garden compost or seed/potting compost:

• Garden compost is a soil improver made from decomposed plant waste, usually in a compost bin or heap. It is added to soil to improve its fertility, structure and water-holding capacity. Seed or potting composts are used for growing seedlings or plants in containers - a wide range of commercially produced peat-free composts are available, made from a mix of various ingredients, such as loam, composted bark, coir and sand, although you can mix your own.

, such as peat-free John Innes No. 3, with added grit to improve drainage. See our guides:

How to repot a plant

If you move your strelitzia outside for the summer, it’s easiest to keep it in its pot, rather than planting it directly into a border, as you’ll need to bring it back indoors before autumn sets in.

Location

Strelitzias need lots of bright light, so are best positioned beside a large sunny window or in a conservatory. Plants may benefit from a little shade while in flower, as strong sun can bleach the vibrant colours.

An established strelitzia needs a lot of space – the large, long-stemmed leaves arch outwards from the clump, which can reach well over 1m (3¼ft) wide.

If you move your strelitzia outside for the summer, choose a warm, sunny, sheltered spot. Strong wind can damage the leaves and snap the stems, or even blow over this often top-heavy plant.

Temperature

Strelitzias are tender tropical plants, so they like plenty of warmth all year round, in a heated room or conservatory. Temperatures should never go below 10–12°C (50–54°F). They also like good ventilation

The introduction of outdoor air into a space, for example, a greenhouse. This airflow can reduce temperature, replenish the gases absorbed by plants and keep down fungal diseases like grey moulds.

once the temperature reaches 20°C (68°F).

Before moving a plant outside for the summer, acclimatise it gradually to outdoor conditions – see our guide to hardening off. And keep an eye on night-time temperatures towards late summer, so you can bring it back indoors before they dip anywhere near 12°C (54°F).

Watering

Strelitzias need regular and plentiful watering in spring and summer – aim to keep the compost

Can refer to either home-made garden compost or seed/potting compost:

• Garden compost is a soil improver made from decomposed plant waste, usually in a compost bin or heap. It is added to soil to improve its fertility, structure and water-holding capacity. Seed or potting composts are used for growing seedlings or plants in containers - a wide range of commercially produced peat-free composts are available, made from a mix of various ingredients, such as loam, composted bark, coir and sand, although you can mix your own.

constantly moist but not saturated. These plants can lose a lot of water through their large leaves, so may need daily watering in warm weather.

Watering should be gradually reduced during autumn. From the end of November, let the compost get fairly dry between waterings.

Humidity

Strelitzias prefer a humid atmosphere, but the air in our homes tends to be quite dry, so mist the leaves regularly or stand the pot in a tray of damp gravel.

Feeding

These are hungry plants and require regular feeding during the growing season

The period of time when an individual plant is in active growth. This will depend on the local climate and light levels, and can vary between different plants, although it is broadly from spring to autumn.

, through spring and summer. Apply a liquid houseplant feed fortnightly.

Every spring, remove the top 5cm (2in) of compost and replace with fresh, to give the plant a boost.

Simply remove any browning or tatty leaves at the base, using a sharp pair of secateurs, to keep the plant looking its best. Also remove the whole flower stalk once each flower fades.

You can make new strelitzia plants by dividing a large clump or by sowing seeds.

Dividing strelitzias

A quick and easy way to produce new strelitzia plants is by division in early spring. Mature plants tend to form new individual plants (or offsets) around the outside of the clump, each with its own set of leaves. Simply remove one or more of these offsets by cutting down through the rootball

The roots and accompanying soil when a plant is removed from a container or lifted from the ground.

, making sure each new plant has a healthy set of leaves and roots. Cutting through the rootball can be a tough job and will need a sturdy pair of secateurs.

Pot up the offset(s) into free-draining peat-free compost

Can refer to either home-made garden compost or seed/potting compost:

• Garden compost is a soil improver made from decomposed plant waste, usually in a compost bin or heap. It is added to soil to improve its fertility, structure and water-holding capacity. Seed or potting composts are used for growing seedlings or plants in containers - a wide range of commercially produced peat-free composts are available, made from a mix of various ingredients, such as loam, composted bark, coir and sand, although you can mix your own.

and water in well.

Perennials: dividing

Growing strelitzias from seed

Strelitzias can be grown from seed, but this does require patience – germination

Germination is the process by which a seed develops into a new plant. It starts with the seed coat absorbing water, expanding and splitting, which allows oxygen and water into the seed so its food reserves can be broken down and used by the embryo for growth. The first root (called the radicle) pushes into the soil to anchor the new plant in place and start absorbing water and nutrients. The first shoot (called the plumule) then grows upwards, out of the soil, towards the light.

can take several months and the resulting plants may take five or even up to ten years to reach flowering size. Seeds may be available in garden centres and are widely sold online.

The seeds have a tough coating, so won’t germinate reliably if simply sown as they are. The best method is as follows:

• Start getting ready to sow in early spring. First remove the orange tufts from the seeds and place the seeds in a plastic bag with a handful of fresh peat-free compost. Keep this in the fridge for two weeks
• Remove the seeds from the plastic bag and carefully nick the seed coat with a knife or scratch it with sandpaper, so that water will be able to get in. Then soak the seeds for a few hours in lukewarm water
• Sow into pots of peat-free seed compost
  

  Seed compost is a free-draining compost formulated for germinating seed. It often contains a mix of fine materials including sterilised loam, coir, coarse sand or grit. It contains low levels of nutrients, as high levels could damage seedlings.

  , spacing the seeds about 2.5cm (1in) apart. Place in a heated propagator
  

  A heated propagator is a portable heated structure with a vented lid and adjustable, constant, thermostatic temperature control. It provides a warm, humid environment to help seeds germinate and cuttings to root quickly.

  at 18–21°C (65–70°F)
• Keep the compost just moist, and air out the propagator
  

  A propagator is a portable, lightweight structure usually plastic, with a vented or unvented lid to provide a humid, slightly warmer atmosphere. It is useful to help seeds germinate and root cuttings. It may have adjustable, thermostatic temperature control.

  daily by removing the lid
• Germination should take four to eight weeks
• When the seedlings
  

  A seedling is a young plant grown from seed.

  have two or three leaves, carefully transplant into individual pots
• Pot on regularly as the plants grow. It may take five years or more before they are ready to flower

How to sow seeds indoors

How to use peat-free compost: for seeds and cuttings

Strelitzias are strong, vigorous plants, but if their growing conditions aren’t suitable, plants may develop various symptoms, including:

• Brown leaf edges and no flowers – slow growth, brown leaf tips and edges, leaf deformities and failure to flower are all signs that the growing conditions aren’t correct. Ensure there is high humidity – if not, mist the leaves daily – and feed and water plants regularly
• Shredded leaves – if you move your strelitzia outside for the summer, give it a sheltered spot. In a windy location the large, tall leaves will soon become shredded and tatty

Check plants regularly for sap

Sap is a fluid that circulates through a plant's vascular system, in a similar way to blood moving through our veins. Phloem sap carries the sugars produced in the leaves by photosynthesis down to roots and other storage organs, as well as carrying minerals and hormones. Xylem sap is watery and transports nutrients absorbed by the roots upwards to the rest of the plant. Some plants leak sap from wounds or pruning cuts, and this is known as bleeding.

-sucking insects, including:

• scale insects
• red spider mites
• mealybugs