Agastache mexicana aka Mexican Lemon Hyssop

Agastache mexicana is a perennial herb from Mexico. It belongs to the mint family, Lamiaceae. Gardeners also call it Mexican giant hyssop or Mexican hyssop. Its native range runs from northeastern to southern Mexico. It grows in subtropical regions, often on high ground. People grow it for food, traditional medicine, and garden flowers.

Plants form clumps of upright stems with many branches. Rhizomes spread slowly below ground and send up new growth. Garden references give a height near 2.6 feet [0.8 metres]. The stated spread is about 1 foot [0.3 metres]. A broader account records stems reaching 4.9 feet [1.5 metres]. Growth proceeds at a moderate pace. The young leaves have a strong scent. Sources describe their flavour as lemon-like or sharp and liquorice-like.

Pink or red flowers bring colour to planted beds. PFAF records flowering in August, with seeds ripening in September. Plants can flower and set seed during their first year. Each flower has both male and female parts. The species is self-fertile, and bees pollinate its flowers. Butterflies and hummingbirds also visit them. These visitors add to its value in wildlife gardens. Growers also plant it for its flowers alone.

Choose a warm site with full sun and some shelter. Shade does not suit this plant. It grows in sandy or loamy soil with good drainage. It accepts mildly acid, neutral, and mildly alkaline soil. The soil may be dry or moist. Reports of winter survival differ, so hardiness remains uncertain. PFAF lists USDA zones 6–10, but its notes give conflicting limits. The Ferns expects little frost tolerance, yet notes survival at Kew. Plants may be short-lived in gardens. Growers can also raise them as annuals. Seeds, spring divisions, and young basal cuttings provide new plants.

Young leaves flavour salads and cooked dishes, and make tea. PFAF also describes eating the flowers. The Ferns reports sales for traditional medicine in Mexico. These uses do not establish that treatments work. Both sources list no known hazards. That does not confirm safety for every person or pet. The supplied accounts name no specific pests or diseases. PFAF does not flag the species as a weed.