How to Prune white lupin?
Deadhead to encourage more flowers

white lupin · Lupinus albus
Also known as: Egyptian lupin; field lupine; lupini bean; white lupine; wolf bean
Grow in light, ideally slightly acidic, well-drained soil in full sun. The roots are nitrogen-fixing, so can be used as a summer green manure if plants are not allowed to seed
Deadhead to encourage more flowers