Plantain lily

This hosta is slow to get started, but as it picks up, it's thick, dark bluish-green oval foliage with prominent ribs makes an impressive leafy show. After midsummer, there's a good show of pale lavender, bell-shaped flowers on top of long stems. Though it can be grown in full sun, you'll lose the distinguishing bluish colour, which needs some shade. As with all hostas, beware slugs ruining the new leaves. If they are a big problem, grow the hostas in pots, and top the compost with sharp gravel.