when did yo plant them

why not a pic??

ken

I planted them this spring. Sorry, here's some pics.
The pink stalky plants are them.

Here is what they look like now.

I don't know where you live or what exposure your penstemons have, but penstemons need good drainage, lots of sun and fairly dry conditions. I have mine growing on gravel in full sun with very occasional watering, and I live in New Mexico.

Cheryl

My guess would be soil is too moist or else retains water. Penstemons do best in well-drained soil. I have them in full as well as part sun, growing in healthy sandy loam and all are thriving.

My penstemons grow in sandy soil, full sun, gravel mulch. As Cheryl said, they need good drainage, and I killed a bunch I planted in average soil; it held too much moisture. I don't know if yours can be saved, but if they were mine, I'd move the mulch out of the way, dig them up, and plant them in a mound of sandy soil so they are above the surrounding soil, and mulch with gravel.