Hardiness: USDA Zone 3a: to -39.9 °C (-40 °F) USDA Zone 3b: to -37.2 °C (-35 °F) USDA Zone 4a: to -34.4 °C (-30 °F) USDA Zone 4b: to -31.6 °C (-25 °F) USDA Zone 5a: to -28.8 °C (-20 °F) USDA Zone 5b: to -26.1 °C (-15 °F) USDA Zone 6a: to -23.3 °C (-10 °F) USDA Zone 6b: to -20.5 °C (-5 °F) USDA Zone 7a: to -17.7 °C (0 °F) USDA Zone 7b: to -14.9 °C (5 °F) USDA Zone 8a: to -12.2 °C (10 °F) USDA Zone 8b: to -9.4 °C (15 °F) USDA Zone 9a: to -6.6 °C (20 °F) USDA Zone 9b: to -3.8 °C (25 °F)
On Apr 20, 2012, rosiesgarden2001 from Gridley, IL wrote:
most penstemon are short lived perennials even where zone hardy; it is so easy to keep them going when you allow some seed to ripen and scratch it in beside the parent. they do rebloom well if deadheaded. i grow on western slope, mix pebbles and moisture plus polymers just under roots, it reduces watering that 1st yr,and they can't drown. i use moisture polymers under all my plants now, and operate as a drought garden except for new plants. don't put mulch close to stems of penstemon--rot., or overwater. drainage essential. be sure to check for zone hardiness. in the case of penstemon,figure 1 zone further N than the chart reads.i love all the varieties of pen., husker red the least, it is a bit boring, but all U of Neb varieties very long lived and reliable.
On Jun 16, 2011, ms_greenjeans from Hopkins, MN (Zone 4a) wrote:
I'm a penstemon fan, even though they are short-lived. I have had pretty good luck with Husker Red if I divide and replant about every other year. I just planted Rondo Mix last year, and it is flowering nicely right now. I got a good mix of pastel colors, and it's very pretty. Hopefully I can keep these going with a similar strategy.
On Jun 27, 2009, art_n_garden from Colorado Springs, CO (Zone 6a) wrote:
'Rondo Mix' is probably my favorite penstemon out of probably 20 varieties I grow- maybe one of the top 10 perennials I grow. It is stout and solid looking, and I agree it does not flop like other penstemons have the tendency to do. I have two different varieties of color - a deep blue/purple and a deep light pink. Both are long blooming and stand out among other flowers.
I have had ease and success at starting them from seed indoors in the winter, and they tend to bloom the first year from seed.
Plentiful flowers on short, sturdy stalks. 'Rondo Mix' does not have the tendency to flop as some other varities of Penstemon barbatus do. One of my favorite Penstemons. Stratification aids germination of seeds. They will rebloom if deadheaded.