When to plant Evening Primrose in Temperate Australia
Temperate zone — applies to Sydney, Melbourne, Adelaide, Perth, Newcastle and similar areas. Growing elsewhere? Cool · Subtropical · Tropical · Arid.
Raise evening primrose seedlings under cover and transplant them out, sowing from September to December in spring or January to April in the cooler autumn window. Barely cover the seed at just 1 mm deep, since it needs light to trigger germination, which takes a patient 21 to 28 days. This is a biennial, so allow the full 365 days from sowing to flowering as the plant builds a rosette in its first season and sends up its lemon-scented evening blooms the next. Space plants 30 cm apart with rows 30 to 60 cm wide. It suits open, sunny beds across Melbourne, Adelaide and Perth gardens.
Sowing calendar — temperate zone
Green months are your sowing window: September to April.
Growing notes
Evening primrose is undemanding once established and copes well with the mild temperate winters of Sydney and Newcastle, where it stays hardy through frost. Give it full sun and free-draining soil; it actually flowers better on lean, unimproved ground than in rich, heavily fed beds.
The most common failure here is damping off in the seed tray. Because the seed is surface-sown and slow, trays kept too wet in a humid glasshouse will rot the fine seedlings before they get going. Sow into a gritty, sterile mix, water from below, and give trays good airflow. Once transplanted, back off the watering.
The second thing to watch is self-seeding. A single mature plant scatters thousands of seeds, and in a warm Adelaide autumn you can end up with a colony you did not plan for. Deadhead spent spikes before the pods dry if you want to keep it contained, or leave a few to naturalise a rough corner.
Because it is biennial, stagger your sowings across both the spring and autumn windows so you always have first-year rosettes coming on behind this season's flowering plants.
Evening Primrose at a glance
| Sowing depth | 1 mm |
|---|---|
| Plant spacing | 30 cm |
| Row spacing | 30-60 cm |
| Germination | 21-28 days |
| Days to maturity | 365 days |
| Frost tolerance | Hardy |
| Method | Plant Seedlings |
Common questions
- how long does evening primrose take to flower from seed
- It is a biennial, so it takes close to a full year — around 365 days — from sowing to bloom. In its first season the plant forms a leafy rosette, then flowers the following spring or summer. Sowing across both the spring and autumn windows gives you plants at different stages.
- why won't my evening primrose seeds germinate
- The seed needs light and is slow, taking 21 to 28 days. If you have buried it deeper than 1 mm it may not come up at all. Surface-sow and press it in gently rather than covering it, and keep the mix just moist, not wet.
- is evening primrose invasive in Australian gardens
- It self-seeds freely and can naturalise, especially after a mild Adelaide or Perth autumn. It is not aggressively weedy, but deadhead the spent flower spikes before the seed pods dry if you want to keep it in bounds.
- does evening primrose need full sun
- Yes, give it full sun for the best flowering. It also prefers lean, free-draining soil and generally blooms more on unimproved ground than in rich, fertilised beds.
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