How to Grow Pansies in Australia

Garden pansy (Viola × wittrockiana) is a hybrid in the violet family, Violaceae, grown as a cool-season annual for its large, often dark-faced flowers. It brightens beds, pots and baskets through winter, and the flowers are edible. The usual failure is timing: seed sown as the weather warms flowers briefly, then stretches and fades.

Three mistakes that matter

1. Sowing as the weather warms. Heat cuts pansies short, and plants raised into warm spring weather soon stretch, stop flowering and die back. Start them in late summer or autumn instead, within the months for your zone in When to plant.
2. Sowing on the surface. Light holds pansy seed back, so a tray left uncovered on a bright bench can give few seedlings or none. Bury the seed and block the light, following the steps in Sowing Seeds.
3. Letting spent flowers set seed. Ripening seed pods take energy the plant would otherwise put into new flowers. Remove blooms as they fade, following Deadheading, and a planting can stay in flower for months.

When to plant

Pansy seed germinates best at about 17 to 22°C, so sow once the worst of the summer heat has passed. Southern gardens traditionally plant seedlings out around Anzac Day. Pansies usually take 110 to 120 days from sowing to flower, so early sowings bring colour from late autumn.

Early in a window, while days are still hot, germinate trays somewhere cool and out of the afternoon sun. Late sowings flower later, carrying colour into spring.

Site, soil and setup

Pansies flower best in full sun through the cool months, with at least 3 hours of direct sun a day. In warm zones, and for spring plantings, choose a spot shaded from the afternoon sun. The soil should drain freely and be rich in organic matter, ideally at pH 6.0 to 6.5.

Black root rot and damping off can linger in soil and old plant debris, so move pansies to a different bed each year.

Container growing

A single plant needs a pot 20 cm or more across and deep, which holds about 5 L. A group needs 10 L or more, such as a 30 cm pot of about 13.5 L. For pots, choose 'Rococo Frilled Mixed' or 'Bambini Mixed'; for hanging baskets, 'Swiss Giants Rhinegold' or 'Arkwright Ruby'.

Use fresh potting mix. Bagged mix can carry Legionella bacteria, so moisten it before you handle it, wear a mask and gloves, and wash your hands when done.

• Watering: water at the base in the morning, keeping the mix moist but never soggy.
• Feeding: fish and seaweed blend at 25 mL per 9 L, fortnightly while the plants grow and flower.
• Position: winter sun, then shelter from the afternoon sun once spring warms, which stretches out the flowering.

Sowing Seeds

Pansies are best started in trays or punnets, where darkness and moisture are easy to control.

Starting under cover

• Sprinkle the seed thinly over fresh seed raising mix in a clean tray or punnet, then cover it with 5 to 6 mm of mix.
• Firm the surface, mist it with a spray bottle, then cover the tray with plastic film pierced with a few holes.
• Add a sheet of newspaper or cardboard over the film to block the light.
• Hold the tray at the germination temperature in When to plant, and expect seedlings in 1 to 4 weeks.
• Lift both covers off the day the first seedlings appear, and give the tray bright light.

Transplanting

• When the first true leaves open, prick out the seedlings (move each into its own cell or small pot).
• Harden off the young plants (get them used to outdoor sun and wind by leaving them out a little longer each day).
• They are ready to plant out at 5 to 10 cm tall, usually 8 to 12 weeks from sowing.
• Allow 20 to 30 cm between plants, and set each no deeper than it sat in the punnet.
• Settle them in with seaweed solution at half strength, 15 mL per 9 L.

'Heartsease Johnny Jump Up' and 'Tricolor' share the collection but are small-flowered violas, covered in Violas.

Care by growth stage

Steady moisture and cool, bright weather decide how long pansies flower. Feeding stays light, because a well-prepared bed does most of the work.

Where growth stalls but the roots look healthy, scratch in a little all-purpose controlled release granular (NPK around 14-5-10) at the label rate.

Deadheading

Start as the first flowers fade and keep going while the plants bloom, so no seed pods form.

• How to cut: cut each fading flower back to just above a leaf, using sharp snips or secateurs.
• How often: go over the plants daily if you can, removing any flower past its best.
• After the first flush: trim the plants lightly, which stops them turning leggy.
• For seed: leave a few pods on the plant until they dry and split into three.
• End of the season: pull plants out once summer heat leaves them straggly, and sow again in late summer.

Companion planting

Pansies pair best with plants of the same cool season that neither shade nor smother them.

Grows well with

• Violas: their spreading habit fills the gaps between the more upright pansies.
• Spring bulbs such as tulips and daffodils: pansies set over the bulbs flower while the bulbs are still below ground.
• Calendula: a taller cool-season annual that sits behind the lower pansies.
• Lettuce and other winter vegetables: pansies tuck into the gaps along the edge of the patch.

Keep apart

• Peas on a trellis to the north: their winter shade falls across plants that need full sun.
• Nasturtiums: they grow rampantly and can swamp low bedding.

Harvesting Blooms

Pick flowers once they are fully open, as heads for eating or with stalks for a small vase.

• Pick early in the morning, while the flowers are well hydrated, or just before you use them.
• For eating, pick only from plants that have not been sprayed.
• Rinse flowers well before they go into food.

Picked flowers keep for a few days in the fridge, on damp paper towel in a sealed container. They suit salads, ice cubes and crystallised cake decorations.

Common problems

No seedlings appear. Light reaching the seed is the usual cause (see Three mistakes that matter), followed by mix that dries out or runs too warm. Read more

Seedlings topple over. Damping off (a seedling rot at the soil line, mostly from Pythium species and Rhizoctonia solani) is favoured by wet mix. Read more

Seedlings are long and spindly. Warmth and too little light stretch them, so grow trays on in the coolest, brightest spot you have. Read more

Plants sprawl and flower poorly. Too much shade is the usual cause, so move pots into more sun or choose a brighter bed next time.

Flowering stops as spring warms. See the first and third points in Three mistakes that matter.

Pests and diseases

Snails and aphids are the usual pests, and moulds and mildews follow damp, shaded or crowded plantings.

Aphids (family Aphididae). These small sap-suckers cluster on stems and new shoots, and infested plants yellow and grow poorly. Blast them off with the hose or use insecticidal soap. Read more

Garden snail (Cornu aspersum) and grey field slug (Deroceras reticulatum). They chew leaves and young plants after dark, especially after rain. Sink shallow dishes of beer as traps. Copper tape stops them on plastic or wooden pots and beds, but corrodes corrugated iron. Read more

Powdery mildew (Golovinomyces orontii). White powdery patches spread across the leaves. Pick off the worst leaves and water early, then spray 1 part full-cream milk to 10 parts water. Read more

Downy mildew (Peronospora violae). Yellow to grey-brown patches form on the leaves, with a mauve growth underneath. Remove affected plants and space the rest so the leaves dry quickly. Read more

Grey mould (Botrytis cinerea). A grey mould rots ageing petals, mostly in cool weather with heavy dew. Clear away spent flowers quickly and water at soil level.

Black root rot (Thielaviopsis basicola). Growth stalls, and brown spots on the roots spread and blacken. Lift and discard sick plants, fix the drainage and put the next planting in another bed.

Prevention first

• Give plants the full spacing from Sowing Seeds, which lets wet leaves dry fast.
• Water at soil level, and in the morning.
• Start every sowing in fresh mix and scrubbed trays.
• Check young plantings by torchlight for snails and slugs.

Tips

1. Plant yellow and blue pansies beside a door or path, where their faint early-morning scent can be noticed.
2. Give children a pot of pansies to pick posies from. Growing from seed with kids has more ideas.
3. Let a few plants drop their seed in a corner, and seedlings may come up by themselves.