| Yes, you're right; as a perennial in zones 8 or 9. I've seen it listed as an annual in zones 4-8. The plants displayed at the Calgary Zoo are on trial for local conditions (zone 3 foothills, high elevation, similar to the mountainous areas of Idaho). It occurs in every state in the US, so it must be coming back as an annual? See the enclosed map. |
Here is a link that might be useful: USDA plant database