Wildflower 101: Monkshood⠀ ⠀ Monkshood is a tall plant with stems that can grow up to 4 feet tall, the flowers resemble larkspur except that Monkshood's upper sepal resembles a helmet or hood rather than a spur. Monkshood can grow in two color forms – a deep blue-purple shown here and a greenish-yellow color. Have you spotted any? This beauty blooms from late-June to late-August.