When to plant
Plant Mirabilis tubers in spring once all risk of frost has passed and the soil has warmed. In cooler climates, tubers can be started indoors in pots and transplanted outside after frost.
Where to plant
Choose a sunny position with at least 6 hours of direct sunlight daily. Mirabilis thrives in warm borders, cottage-style gardens and containers. It tolerates heat very well and flowers best in full sun.
Preparing the soil
Loosen the soil to 20–25 cm and enrich with compost or well-rotted manure. Mirabilis grows well in most garden soils but performs best in fertile, well-drained ground. Improve clay soils with grit; enrich sandy soils with organic matter.
Preparing the tubers
Select firm tubers and remove any shrivelled or damaged sections. Do not soak Mirabilis tubers. Handle gently, as they can be brittle.
Planting the tubers
Plant tubers 5–7 cm deep with the tip or eye facing upward if visible. Space 25–30 cm apart. In cooler climates, planting slightly shallower (around 5 cm) helps warm the soil more quickly. Water lightly after planting.
After planting
Keep the soil lightly moist until shoots appear. Mirabilis grows quickly as temperatures rise. Avoid overwatering, as tubers may rot in soggy conditions.
During growth
Water regularly during hot, dry spells, but allow soil to dry slightly between waterings. Feed every 3–4 weeks in summer with a balanced liquid fertilizer. Deadheading is not necessary — Mirabilis blooms continuously.
After flowering
Mirabilis is tender in cold climates. After the first frost, lift the tubers, dry them, and store them in a cool, frost-free place until spring. In mild climates, tubers can remain in the ground with a protective mulch.
Extra tips
Mirabilis is highly attractive to moths and evening pollinators. It’s an excellent container plant and creates a bushy, colourful display all summer. Flowers open late afternoon and close the next morning — true to their name, “four o’clocks.”
