When to plant Wallflower in Temperate Australia
Temperate zone — applies to Sydney, Melbourne, Adelaide, Perth, Newcastle and similar areas. Growing elsewhere? Cool · Subtropical · Tropical · Arid.
Raise wallflower seedlings from January to May and transplant them out through autumn, sowing seed about 6 mm deep. Germination takes 14–21 days, and this is a plant for the patient gardener; it needs around 180 days to flower, so an autumn sowing gives the fragrant spring display it is loved for. Space transplants 20–30 cm apart in rows 25–30 cm apart in a sunny, well-drained spot. Hardy and richly scented, wallflowers thrive in the cool winters and mild springs of temperate gardens around Melbourne, Adelaide and Ballarat's warmer fringes.
Sowing calendar — temperate zone
Green months are your sowing window: January to May.
Growing notes
Wallflowers are a classic cool-season biennial-style flower grown for their warmly scented spring spikes, and the long 180-day run to bloom is the defining feature to plan around. Sowing seedlings from January to May and growing them on through autumn and winter sets them up to flower as spring arrives, which is exactly the rhythm temperate gardens in Adelaide and Melbourne suit.
Drainage is everything. Wallflowers are prone to root rot and the fungal disease clubroot in wet, heavy soil, and a waterlogged winter bed is the quickest way to lose them. Plant into free-draining ground, raised beds, or improve clay with grit and compost first, and choose a sunny position for the strongest scent and sturdiest plants.
Because wallflowers are brassicas, they share that family's pests and diseases. Clubroot is the big one; never grow them where cabbages, stocks or other brassicas have recently been, and keep the soil pH near neutral with a little lime. Cabbage white caterpillars and aphids can also trouble them, and exclusion netting keeps the worst off young plants. Pinch out the growing tip of young seedlings to encourage a bushier, multi-stemmed plant with more flower spikes. Once flowering, deadhead spent spikes to prolong the display, and treat plants as short-lived; most are best replaced after their spring season rather than carried on.
Wallflower at a glance
| Sowing depth | 6 mm |
|---|---|
| Plant spacing | 20-30 cm |
| Row spacing | 25-30 cm |
| Germination | 14-21 days |
| Days to maturity | 180 days |
| Frost tolerance | Hardy |
| Method | Plant Seedlings |
Common questions
- Why do wallflowers take so long to flower?
- They are naturally slow, needing about 180 days from sowing to bloom. Sown as seedlings from January to May and grown through autumn and winter, they flower in spring, so the long wait is normal and worth planning for.
- Why did my wallflowers rot over winter?
- Almost always poor drainage. Wallflowers hate wet, heavy soil and are prone to root rot in a waterlogged winter bed. Plant them into free-draining ground or raised beds, and improve clay soils with grit and compost before planting.
- Can I grow wallflowers where I grew cabbages?
- It is risky. Wallflowers are brassicas and share clubroot with cabbages and stocks, so growing them in the same soil spreads the disease. Rotate to a fresh bed and keep the pH near neutral with a little lime to reduce the risk.
- How do I get bushier wallflowers?
- Pinch out the growing tip of young seedlings. This encourages the plant to branch into multiple stems and produce more flower spikes rather than one tall, sparse stem. Space plants 20–30 cm apart to give them room to fill out.
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