How to prune rocky mountain penstemon

Deadhead during flowering (late spring to midsummer); cut back to basal rosette in early spring. Snip spent flower stalks back to the nearest healthy leaf or side shoot. In early spring before new growth, cut all old stems to 2–3 inches above ground, taking care not to damage the emerging rosette.

Deadhead as needed during bloom; annual cut-back in early spring. Rocky Mountain penstemon is a hardy, low-maintenance perennial. Deadhead spent spikes during the flowering season to encourage re-bloom. Leave stems standing over winter for frost hardiness and wildlife value. Cut the whole plant back to just above the basal rosette in early spring. Avoid heavy pruning — it can shorten the plant's life.

Snip spent flower stalks back to the nearest healthy leaf or side shoot. In early spring before new growth, cut all old stems to 2–3 inches above ground, taking care not to damage the emerging rosette.