How to Grow Tuberose for Scented Stems

To grow tuberose in the UK, think warmth first. Start the tubers in pots at about 20C in March, then move them to your sunniest, most sheltered spot once the frosts have passed. Give them that heat and a single spike will scent a patio or conservatory on a summer evening.

Tuberose (Polianthes tuberosa, now often listed as Agave amica) comes from Mexico and has no frost tolerance at all. It is a pot plant for summer, brought in for winter, much like other tender bulbs. If you like scented bulbs with a bit of a challenge, it pairs nicely with sun-loving Leucocoryne, the glory of the sun, which is a spring bloomer rather than a late-summer one.

Why tuberose needs warmth to get going

Tuberose won’t grow until it’s warm. A tuber in cold compost just sits there, and if the compost is damp it may rot.

It also needs a long season. Expect around four months from potting up to the first flowers. Lose a few weeks to a cold start and you can run out of summer before the spike opens. That’s why a heated propagator, a warm airing cupboard or a sunny windowsill above a radiator makes such a difference at the start.

Single or double tuberose: which to choose

For a first go, choose a single tuberose. ‘Mexican Single’ has starry white flowers, a powerful scent and is the most reliable.

Double ‘The Pearl’ has fuller, many-petalled flowers that look lovely in a vase. It is a little slower and fussier about heat. Pink-tinged varieties such as ‘Pink Sapphire’ are also sold, if you want a change from white.

Buy plump, firm tubers in late winter or early spring. Turn down any that feel soft, light or shrivelled. Small tubers may only make leaves in their first year.

Single on the left, double on the right. The single is the easier one to get flowering.

How to start tuberose tubers indoors

Pot tubers up in March or early April, one tuber per 15cm pot or three to a 30cm pot. Use peat-free multipurpose compost mixed with some grit or perlite so it drains freely.

Set the tip of each tuber just at the surface, water once, then keep the pots somewhere warm until shoots appear.

1. Set each tuber so its pointed tip sits just at the compost surface.
2. Water once, lightly.
3. Put the pots somewhere warm, at about 20C.
4. Keep the compost barely moist until a shoot appears.
5. Move into full light as soon as shoots show.

The classic mistake is watering a dormant tuber too much. It can’t use the water until it has roots, so it rots instead. Once leaves are growing well, you can water more.

Growing tuberose in pots outside for summer

Pots let you chase the heat. Once all risk of frost has passed, usually late May or early June, harden plants off over a week. Then stand them in the hottest, most sheltered spot you have, such as a south-facing wall or a sunny patio. The guide to hardening off half-hardy plants explains how.

In summer, water whenever the top of the compost feels dry. Once a flower spike appears, feed every two weeks with a high-potash liquid feed such as tomato feed. Tall spikes can lean when full of flowers, so tie them loosely to a cane.

If the summer turns cold and wet, a greenhouse or conservatory gives more reliable flowers. Some growers keep their plants under glass all season.

A warm wall and a sunny patio give tuberose the heat it needs. Pots are easy to move back inside in autumn.

When tuberose flowers and when it smells best

Tuberose flowers from August to October from a March start. The spike grows to about 60-90cm tall, and the waxy flowers open from the bottom upwards over a few weeks.

The scent is heavy, sweet and creamy, and it is strongest in the evening and at night. Put pots near a back door, a bench or an open window where you’ll enjoy it. Nicotiana and other evening-scented plants make good companions; see the guide to designing a moon garden for more ideas.

Each tuber usually sends up one spike. A big tuber may manage a second, smaller one.

Under glass, tuberose gets steady warmth and long, straight stems, which is handy if you want them for cutting.

Cutting tuberose for the vase

Tuberose makes a superb cut flower. Cut the stem when the lowest two or three flowers have opened. The buds above keep opening in the vase.

Strip the lower leaves, recut the stem and stand it in fresh water. Change the water every couple of days and stems usually last about a week. The guide to conditioning cut flowers has more tips for longer vase life.

A few cut stems will scent a whole kitchen in the evening.

Lifting and storing tuberose tubers over winter

Tuberose is killed by frost, so it can’t stay outside or in an unheated greenhouse over winter. Bring pots in or lift the tubers before the first frost, usually in October.

Dry the tubers for about a week, then store them in dry vermiculite somewhere warm and frost-free.

Cut the foliage back, knock the tubers out and brush off loose compost. Let them dry for about a week somewhere airy and frost-free. Then store them in dry compost or vermiculite somewhere warm and dry indoors, such as a spare room. Check them every month and throw out any that go soft. The guide to storing flower bulbs covers the basics.

The main tuber rarely flowers again. Grow the offsets on in pots for a year or two, or buy fresh tubers each spring for a sure show.

Month-by-month tuberose calendar

Common mistakes with tuberose

• Starting too cold. A chilly windowsill won’t wake the tubers. Give them about 20C until shoots appear.
• Starting too late. Pot up in May and frost may arrive before the spike opens. Aim for March.
• Overwatering at the start. Keep the compost barely moist until shoots show, or the tuber can rot.
• A shady spot. Without full sun and warmth, you’ll get leaves but no flowers.
• Expecting a repeat show. The main tuber usually flowers once. Plan to grow on offsets or buy new tubers.

Other tender bulbs to grow with tuberose

Tuberose fits in with other summer bulbs that you lift and store each winter. If you already grow dahlias or gladioli, you have the routine. Tuberose just needs more warmth at the start. Browse more ideas in the plants section.

Now your tuberose is sorted, read the guide on how to overwinter tender plants to keep it and your other tender treasures safe until spring.

Frequently asked questions

Can you grow tuberose outdoors in the UK?

Only for the summer months, after the last frost. Start tubers indoors in spring, put pots outside in a sun trap from late May or June, and bring them back under cover before autumn frosts.

Why won’t my tuberose flower?

Usually it started too cold or too late. Tubers need warmth to wake up and a long, hot summer to build a spike. Small offsets also often grow leaves only for a year or two before they are big enough to flower.

What temperature does tuberose need to start growing?

Around 20C at the roots is ideal. A heated propagator or a warm spot near a radiator works well. In cold, damp compost the tubers sit still and can rot.

What is the difference between single and double tuberose?

Singles are simpler, more reliable and strongly scented. ‘Mexican Single’ has starry single flowers. Double ‘The Pearl’ has fuller, many-petalled flowers and looks showier, but it needs more warmth to do well.

Do tuberose bulbs come back every year?

The main tuber usually flowers only once. It then makes small offsets that need a year or two of growing before they flower. Many gardeners simply buy fresh tubers each spring for a sure display.

How do you store tuberose tubers over winter?

Keep them dry, frost-free and fairly warm. Lift before the first frost, cut off the leaves, dry the tubers for a week, then store them in dry compost or vermiculite indoors.

When does tuberose flower in the UK?

From August to October, from tubers started in March. The flowers open from the bottom of the spike upwards over a few weeks, and the scent is strongest in the evening.