One of the most popular garden specimen century plants has long been Agave parryi subspecies truncata. Due to their distribution in the Southwest US and Mexico, the hardiness of the various populations varies tremendously. These small (relatively speaking) century plants are mass-market landscape staples in warm temperate and frost-free parts of the desert southwest. Try as we might, we could not get them to overwinter in our Raleigh, NC gardens. Since the late 1980s, we have killed 28 different clones of Agave parryi ssp. truncata, trying each in a slightly different habitat, hoping for better success. You would think a sane person, would discontinue trying after this many attempts, but that didn’t happen.
In 2005, a clone was shared with us, from agave guru Howard Gentry’s wild collection, growing at the Huntington Botanic Garden in California. To our excitement, this clone sailed through our winters in the ground, although it was very slow to offset. In 2010, we acquired a clone from Mountain States Nursery in Arizona, shared by plantsman, Hans Hansen. Like Agave ‘Gentry’s Blue’, this clone was solidly winter hardy here, but this clone was a prolific offsetter. We have built up numbers of each, introducing Agave parryi ssp. truncata ‘Gentry’s Blue’ in 2024, which will be followed by Agave parryi ssp. truncata ‘Hardy Boyz’ in January 2026. This has been a long, 35 year project, but thank goodness, we’ve finally been able to get these two great clones into commerce. Now, the search begins for a winter hardy variegated form.
They look wonderful!
Hi Tony,
Have you ever thought about finding out the mutation that makes it cold hardy? I am a plant biologist working cold tolerance. I am curious what that might be.
Plant winter hardiness is quite complex, and has been studied for years. Instead of jumping in, I’ll direct you to the on-line book, Plant Cold Hardiness (1987) by PH Li, THH Chen. There are many other articles on the subject, but most are behind academic paywalls.
Hi Tony, indeed there are many studies on cold hardiness. It would be nice to get funding to figure out the genetic variation that confers cold hardiness in each of the horticultural variety (each might be different)!
We love the idea…let us know if you get funded.