Gardenia Grandiflora Star

Nearly every gardenia sold in Australia is a tight double, which is what makes Grandiflora Star worth a second look. It opens large single flowers with broad, flat, overlapping petals set in a star, white on opening and ageing to cream against glossy dark evergreen leaves on an upright, moderately dense shrub. The scent is heavy and carries on warm evenings, so its place is beside a doorway, a path or an outdoor table rather than at the back of a bed where the flower shape is lost.

Pots, pH drift and pale new leaves

Part shade with shelter from hot afternoon sun is the position, and it does well in warm temperate and subtropical gardens where nights stay mild through the flowering season. In the ground it wants moist, acidic, free draining soil with compost through it, mulch over the roots, and steady water in summer rather than heavy soakings after a dry spell.

Most plants of this one end up in pots, though, and that is where the failure shows. Potting mix breaks down over a couple of seasons, drainage falls away, and in hard water districts every watering leaves a little more lime and salt behind until the mix is no longer acidic at all. The plant answers with pale new leaves marked by dark green veins, then drops its buds. Repot into a fresh mix formulated for acid loving plants every second spring, use rainwater where you can, flush the pot occasionally with a long slow watering to carry salts out the base, and keep chelated iron on hand rather than assuming the plant simply needs more fertiliser.

Single flowers against the doubles in this range

The comparison worth making is with Magnifica, also a large flowered gardenia but a fully double one on a coarser, broader frame. Doubles hold their shape longer and read as more formal; the single star opens flat, shows its centre and looks looser in a bed. Florida stays the choice for a clipped low hedge, since it holds a tighter face and Star reads looser under regular shearing. If you want that same scent at ground level instead, Radicans delivers it on a low spreading frame. Pick Star for a feature pot, a courtyard corner or a planting beside a seat, where individual flowers get looked at. More in flowering plants.

Deadheading, light pruning and feeding

Deadhead spent flowers as they brown, which keeps the plant tidy and reduces the fungal spotting that follows old petals in humid weather. Repot or refresh container plants in early spring as growth starts, well before the flower buds form. Prune lightly once the main flush ends, shaping rather than cutting hard, and finish before autumn so the wood carrying next season's buds is left alone. Feed in early spring and again after midsummer with an acidic fertiliser, and in a pot add a fortnightly liquid feed at half strength while it is flowering. Check leaf joints for mealybug through warm humid spells.

Choosing a size

This plant is available in 3 sizes, from 140mm up to 200mm, priced from $16.95 to $29.95 per plant. The size shown is the pot the plant arrives in, which is the rootball, not the height of the plant. These are younger plants, priced for planting in quantity, and they establish quickly once in the ground. Not sure which to choose? Read our guide to when to plant in Australia.