Lupines do best in full sun and well draining soil so that its tap root can go deep and regular water, at least one inch of water per week or more during hot, dry conditions. Does not need supplemental fertilizer as lupines do well in nutrient poor soils. If all the growing conditions have been met, look for snails or slugs or inspect the foliage closely for sucking insects such as aphids, scale or mealybugs that suck the nutrients from leaves and branches. If there are snails or slugs use a snali/slug control containing iron phosphate, safe for small pets and children and if sucking insects wash off and if the infestation is extensive, use a horticultural oil recommended by your local garden center. Confirm the problem with your local garden center and recommended control.