How do I care for and maintain Lupinus polyphyllus?

Answer 1

Lupinus polyphyllus need very well drained soil. This is why many people have trouble growing them in clay and those growing in sand may do better- even to the point of the plants becoming invasive. Soils on the acid side are preferred as are those enriched with humus. They usually prefer full sun, but in some areas will grow in part- shade. Roots need to be kept cool by mulching. They do require adequate amounts of water.
Always dead-head the flowers to prevent seed forming which will reduce flowering and shorten the plant's lifespan. In any case the seed is highly toxic. They are relatively short-lived, but you can take cuttings.