Also known as giant hyssop this unusual herbaceous perennial produces tall slender stems of yellow tubular flowers encased in contrasting deep purple calyces these bright and colourful blooms are attractive to bees and butterflies and are perfect for bustling cottage garden borders patio pots and exotic planting schemes as an added bonus the minty aromatic foliage of agastache plants are disliked by slugs and snails33 easy to grow and drought tolerant too agastache 39summer glow39