How to grow Rosella in Australia
Rosella is a fast growing annual hibiscus grown for its fleshy red calyces, which make a deep red jam, cordial and tangy hibiscus tea. It comes from Africa and loves heat, so it is easiest in Queensland and the tropics, and a few plants give hundreds of calyces.
At a glance
When to sow by region
| Region | When to sow | Regional note |
|---|---|---|
| South East Queensland | September to November | |
| Northern Rivers NSW | September to November | |
| Sydney & Coastal NSW | October to December | Sow Oct to Dec in the warmest spot. Rosella needs a long, hot season and is frost tender, so start it early in pots if you can. |
| Melbourne & Victoria | November and December | Marginal. Sow Nov to Dec in the hottest, most sheltered spot; plants may not flower before the cold arrives. |
| Adelaide & SA | October and November | Sow Oct to Nov after the last frost in a warm, sheltered spot, and water well through summer. |
| Perth & WA | October to December | Sow Oct to Dec once the soil is warm, and water deeply on sandy soil through summer. |
| Tasmania | Not suited | Not suited. Rosella needs a long, hot season that Tasmania does not have. |
| Canberra & ACT | Not suited | Not suited. The season is too short and frost kills the plants. |
| North Queensland | October to December | Sow Oct to Dec in the build up and early wet season, as in the Top End. Plants flower in autumn as the days shorten. |
| Darwin & Top End | October to December | Sow Oct to Dec. The Darwin sowing calendar from the NT Government sows rosella in these months, with 16 to 20 weeks to the first picking. |
Not to be confused with: Ornamental hibiscus, the shrubs grown for their big flowers. See our Hibiscus guide.
Where to plant
Grow rosella in full sun in fertile, well drained soil with compost dug in. It needs a long, warm season to reach flowering, so in cooler districts start it as early as the weather allows.
Plants flower in autumn as the days shorten, whatever their size, so early sowing gives bigger bushes and more calyces.
- South East Queensland and the Northern Rivers: sow from September to November.
- North Queensland and Darwin: sow from October to December. The NT Government's Darwin calendar sows rosella in these months, with 16 to 20 weeks to the first picking.
- Sydney and Perth: sow from October to December in the warmest spot.
- Adelaide and Melbourne: marginal. Sow in late spring in the hottest, most sheltered spot.
- Canberra and Hobart: not suited, as the season is too short and frost kills the plants.
How to plant
- Wait until the soil is warm in spring, or the build up in the tropics.
- Sow seed about 1 to 1.5 cm deep, in pots or where it is to grow. Gardening Australia suggests keeping a seed tray standing in water so the mix never dries out; seedlings appear within about three weeks, often sooner.
- Plant out or thin to about 1 to 1.5 m apart.
- Pinch out the growing tips of young plants a few times until about January to make them bushy, as Gardening Australia recommends.
- Mulch and water regularly while plants establish.
Watering and feeding
Keep the soil moist but not soggy, and water deeply in dry spells, especially once flowering starts. Mulch helps on sandy soil.
Dig in compost before sowing and side dress with a balanced organic fertiliser once plants are growing strongly. Too much nitrogen late in the season gives leaves rather than flowers.
Pruning and care through the year
- Tip prune young plants until early summer for a dense, well shaped bush.
- Stake tall plants in windy spots.
- Pick calyces regularly once flowering begins so the plant keeps flowering.
- Pull the plants out once cold weather stops flowering; rosella is grown as an annual.
Harvesting
Gardening Australia says the young leaves can be picked from about 6 weeks, and the calyces are ready when plump, at about 5 to 6 months. Snip each calyx about 10 days after its flower drops, while it is still fleshy and tender rather than dry and woody.
Push the green seed pod out of each calyx with a small tube or the end of a teaspoon before cooking or drying. Fresh calyces keep about a week in the fridge; dried ones keep a year or more in a sealed jar.
Growing in pots
Rosella grows well in a large pot at least 40 cm wide, in quality potting mix and full sun. Water often in hot weather and feed every few weeks.
Using it
Simmer the calyces with sugar for rosella jam, which sets well on its own, or steep them for cordial and a tart, caffeine free hibiscus tea. They also suit syrups, sauces and chutneys, and the young leaves are cooked as a sour green.
Propagation and saving seed
Let a few calyces dry on the plant at the end of the season, then collect the seed from the pods and store it in a cool, dry place for next spring. Gardening Australia notes plants grown from cuttings tend to yield less, so grow from seed.
Varieties
- Red rosella
- Rico
Companion planting
Rosella is a big plant, so give it room and keep low crops on its sunny side.
Good companions
- Marigold Brings hoverflies and other helpful insects that eat aphids.
- Nasturtium A groundcover that shades the soil and draws aphids away.
Pests and diseases
Gardening Australia names mealybug and aphid as the worst pests of rosella.
Pests to watch for
- Mealybug White, cottony clusters on stems, buds and calyces.
- Aphids Clusters of small insects on new growth and flower buds.
Rosella is rarely troubled by disease.
Common questions
When do I sow rosella?
In spring once the soil is warm, from about September to November in South East Queensland. In the tropics, sow from October to December, as the NT Government's Darwin calendar does.
Why is my rosella not flowering?
Rosella flowers in autumn as the days shorten, so plants sown in spring grow leaves all summer and only flower from about March or April. Late sowings flower on smaller plants.
Which part of rosella do you eat?
The fleshy red calyx around the seed pod, picked about 10 days after the flower falls. The young leaves are also eaten as a sour green.
Is rosella native to Australia?
No. Rosella comes from Africa, though it is a long time favourite in Queensland and northern gardens and is often treated as bush tucker.
Is rosella the same as hibiscus?
Rosella is a hibiscus, Hibiscus sabdariffa, but it is an annual food crop, unlike the ornamental hibiscus shrubs grown for their flowers.
Can I grow rosella in Melbourne?
It is marginal. Sow in late spring in the hottest, most sheltered spot, or in a large pot against a warm wall, and expect a small crop before the cold arrives.
Sources we checked: NT Government: Vegetable sowing calendar for Darwin and Katherine regions; Gardening Australia plant finder: Rosella; ABC Rural: Rosella hibiscus hails from Africa.