Penstemon mensarum, Grand Mesa Beardtongue
Some of the bluest flowers I’ve ever seen belong to Penstemon mensarum. This penstemon is native to western Colorado, specifically Mesa, Delta, and Gunnison Counties, and is easy to grow in the Tahoe garden. This penstemon is a bit unusual in that it can tolerate fairly regular watering. In my garden, it gets a good soaking every one to two weeks. It will survive on much less, but look wilted and unhappy in hot weather. I grow this species in a sunny area next to some Aspen trees. I also have a plant growing against a southwest facing wall of the house.
Penstemon mensarum gets up to 2 feet tall and 18 inches wide, and is tolerant of hot sun, extreme cold, wind and violent hailstorms. It should get at least three to four hours of direct sunlight a day, otherwise the flower spikes get elongated and droopy. There are lots of gophers and voles in my yard. This penstemon does not seem to be one of their favorite snacks, which is nice! Over the years they have eaten only one plant. Penstemon mensarum combines beautifully with bright-red Firecracker Flower (Ipomopsis aggregata). They both like similar conditions and bloom at the same time. This plant is pollinated by bees and hummingbirds.
I originally purchased seed from the now-defunct Rocky Mountain Rare Plants. This company was a wonderful resource for all sorts of unusual and beautiful alpine plant seeds. Though I haven’t bought anything from them yet, Western Native Seed looks like a good place to purchase penstemon and other western native seeds: http://www.westernnativeseed.com/wildflowers.html As of this writing (April 2012) High Country Gardens sells Penstemon mensarum plants: http://www.highcountrygardens.com/index/page/product/product_id/3660
For anyone interested in growing penstemons in the garden, I’d highly recommend the book, Penstemons, by Robert Nold, an author from Lakewood, Colorado. Northwest Penstemons by Dee Strickler is also a wonderful book, and is loaded with color photographs.