You did?? Ah, I would love to work in some type of nursery/gardening what-have-you. I've been looking into them a bit, and reading what Debby linked, but I haven't found anything cold hardy to zone 4, only down to 5.Beautiful day to be outside here in NJ. Pushed this body to just about its limits. Fresh pot has been brewed as coffee was needed - have at it in good spirit.
Burger King burgers kill my gut - haven't eaten there in 30 years.
Many of the commercially available varieties are either non hardy or minimally hardy. There are hardy varieties that can handle very cold weather. Generally they tend to be small flowered varieties - many of them with Japanese origins. In another lifetime I worked in an ornamental display garden. One of my projects was growing mum baskets, cascades, and espaliers for autumn display. Garden was owned by Doris Duke the tobacco heiress, and she preferred the Japanese varieties.
Was the garden you worked in amazing?