Purple Giant Hyssop Agastache scrophulariifolia
Purple Giant Hyssop is a perennial shrub native to Canada and the lower 48 states. It blooms Jul – Oct.
More about this plant
Agastache scrophulariifolia, also known as the purple giant hyssop, is a perennial plant that grows throughout the United States and northern Ontario, Canada. Its name comes from the similarity of its leaves to plants of the genus Scrophularia. It is a beneficial plant to pollinators and is noted for its medicinal properties, as many plants in the mint family are. It tends to grow in disturbed or open areas where it does not have to interact with non-native competitive plants. Wikipedia →
Growing & care
USDA PLANTS · TRY- Hardiness
- ≥ zone 5 derived from its U.S. range
- Lifespan
- Perennial
- Flower colour
- White AI AI image-analysis of community-science photos (~87% expert agreement) — not a botanical record
Wildlife & pollinators
How pollinator value is scored →❧ Caterpillar hosts ~2 caterpillar species
Agastache supports ~2 caterpillar species.
Native butterfly & moth caterpillars are the base of the terrestrial food web — most songbirds rear their young almost entirely on them. As a host for native Lepidoptera this is a modest genus.
Recorded feeding on Agastache in North America, including:
✦ Bees 27 bee visitors
27 native & managed bee species are documented visiting Purple Giant Hyssop — the 12 most-recorded:
+ 6 more bees → ↑ show fewer
Wildlife & visitors 11 nectaring
Open records of who else uses Purple Giant Hyssop — a generalist food-web signal, kept separate from the keystone Ecological Value.
11 adult butterfly & moth species are recorded nectaring at its flowers — the most-recorded:
Related plants
More Agastache →
How we know this (2) Methods & honest limits
We take the plant’s U.S. county range and look up each county’s long-term climate, then summarise: native rainfall = the median annual rainfall across its counties; heat tolerance = the warm end (90th percentile) of average temperature across its range (mirroring how our cold-hardiness floor uses an extreme). Counties + medians blunt the roadside/observer bias that makes point-level climate unreliable. Needs at least five placeable counties.
Honest limits: A realized, sampling-biased niche (where it has been recorded, not its physiological optimum), and county climate is coarse — large Western counties span deserts and mountains. Derived guide, never a measured fact.
McKenzie et al. assigned each species a flower colour with a GPT-4V vision model over iNaturalist photos. We use the confident tier plus a separately-labelled lower-confidence top-up (mostly inconspicuous green/brown flowers), and render it as a small tint — never as an asserted fact, and kept out of the written synopsis.
Honest limits: AI image inference (~87% expert agreement on the confident tier); a decorative, confidence-tiered indicator, not a measured trait.
Sources for this entry (20) Open & cited
Cite this page Open data, please attribute
PlantKey’s data is open under CC BY-SA 4.0 — free to reuse and adapt, with attribution and the same licence. Photos keep their own per-image licence + credit (see Sources above).
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