Hydrangea macrophylla 'Merveille Sanguine' - one of the very best hydrangeas. The whole plant has an extra dose of redness from the flowers to the stems and leaves. The leaves also have good autumn colour.
Helleborus foetidus 'Wester Flisk' - a superb form of the native hellebore found in Mamie Walker's garden in Fife, Scotland. Shade-tolerant, but red colouring in the stems develops more strongly when grown out in the open.
Tiarella 'Spring Symphony' - lightly scented flowers in late spring to early summer. The leaves knit together to make a light ground-cover with year-round interest - lovely with spring bulbs like daffodils.