When to plant Lupin?

Lupins thrive in full sun or partial shade, though flowering is strongest with at least six hours of direct sunlight daily. They prefer sandy soil or loam with good drainage and slightly acidic to neutral pH; avoid heavy clay or waterlogged ground, as lupins are prone to root rot in poorly drained conditions. Before planting, dig over the soil to a spade's depth and incorporate some well-rotted compost or leaf mould to improve structure, but don't add lime or manure, which can inhibit the nitrogen-fixing bacteria in their roots. Plant lupins in March, April, September or October. If planting container-grown specimens, dig a hole slightly larger than the root ball, set the plant at the same depth it was growing in the pot, and backfill with soil, firming gently. Space plants 45 cm apart to allow for their mature spread of 40–60 cm. If sowing seed directly outdoors, sow in March or April after the last hard frost, or in September for germination the following spring. Scarify the hard seed coat with sandpaper or nick it with a knife to improve germination, then sow 1–2 cm deep. Water thoroughly after planting to settle the soil around the roots. Apply a 5 cm layer of mulch around the base, keeping it clear of the crown to prevent rot. Young plants may need staking in exposed sites, as the tall flower spikes—reaching 80–120 cm—can be top-heavy. Lupins establish a deep taproot, so avoid transplanting once settled.