USDA NRCS, Public domain, via Wikimedia Commons
Purple Giant Hyssop sets soft plumes of the palest purple flowers that top out at 6 feet, soaring above most other plants in the garden. The individual blossoms open over a period of several weeks in the fall.
From seed, it is easy to grow, but be mindful that the first blooms will typically appear in the second year. With the purple giant hyssop, the best practice is to start seeds indoors about 8 weeks before the latest frost date in your location. When you’re ready to transplant outdoors, find a spot that gets plenty of direct sunlight. Plant in dry, sandy, light, rocky soil and water moderately. Be mindful that it does not like to be in a crowded area; leave lots of room for it to grow without competition.
Quick Growing Guide
Botanical Name: Agastache scrophulariifolia
Also Called: Figwort Giant Hyssop
En français: Agastache à feuilles de scrofulaire
Water: Medium-Wet, Medium, Medium-Dry
Pruning Giant Hyssop
Pruning is an essential step in developing your hyssop for a fresh bloom and a healthy plant. To revitalise a purple giant hyssop plant, cut the stems to as low as 2 inches (5 cm) from the ground. The pruning scissors or knife must be sterilised. This task is best done in early spring.
The long bloom time, combined with high nectar content, makes this plant highly attractive to bees and butterflies, including the endangered Rusty Patched Bumblebee.
Birds feed on the seeds that follow.