Azure Monkshood After everything else in the garden has quit blooming, the intense amethyst-blue hooded flowers of Azure monkshood (Aconitum carmichaelii) remain intact. The flowers and leathery foliage can even survive a freeze. The sturdy spikes of Monkshood grows 4 to 6 feet tall and bloom in October and November. These plants like partial shade to full sun. One of our favorite varieties is 'Arendsii'.