Palmer penstemon

Year-round

Palmer's penstemon is a fragrant, fast-growing perennial from desert mountains in California, Arizona, and Utah. It is not documented as native to Texas, but it is one of the most widely planted Southwest xeriscape penstemons and generally performs well in hot, dry, alkaline conditions like El Paso's.

• Plant in full sun in dry, rocky, well-drained soil. Lady Bird Johnson Wildflower Center lists its native soil as dry and rocky with low water needs, a close match to El Paso's caliche.
• Avoid fertilizer and avoid planting in old garden beds with rich, worked soil. This species is prone to root problems in soil that stays too fertile or too wet.
• Water established plants once or twice a month at most. Overwatering is the most common way this species is lost in cultivation.
• It is short-lived, typically 4 to 5 years, so plan to let it reseed or take cuttings rather than expecting a single planting to last indefinitely.

Its upright flower spikes and fragrant blooms make it a good front-bed accent, but plan for gaps every few years since it is short-lived.

Fall

Fall is a lower-water, lower-maintenance season for this plant, with milder El Paso temperatures matching its preference for dry, temperate conditions.

• Continue infrequent watering, no more than once or twice a month, as temperatures cool.
• Fall is a reasonable time to collect and sow seed if you want to replace plants nearing the end of their 4 to 5 year lifespan.
• Avoid cutting the plant back hard in fall. Leave most foliage in place heading into winter.
• Skip mulch heavy in organic matter around the crown. Keep the area lean and well drained.

Winter

Palmer's penstemon is adapted to cold desert mountain winters, so El Paso's freezes are generally within what this species can handle once established.

• Stop supplemental watering almost entirely in winter except during extended dry spells.
• Leave dead or dormant foliage in place through winter rather than cutting it back, it offers the crown some protection during freezes.
• Good drainage matters most in winter. Wet, cold soil around the crown is the most likely way to lose this plant to winter weather.
• Wait for clear new growth in spring before deciding a plant did not survive, since it can be slow to show new growth after a hard freeze.

Spring

Spring is peak bloom season for Palmer's penstemon and also the best time to plant new starts in El Paso before summer heat sets in.

• Expect flowering to begin around May, consistent with its documented May-to-June bloom window, sometimes stretching into early summer here.
• Plant new starts after the last frost into unamended, fast-draining soil, watering twice a week only until roots establish.
• Deadhead spent flower spikes to extend bloom and to limit excess self-seeding if you want a tidier bed.
• Watch young plants during dry, windy spring weeks. New transplants can dry out fast in exposed, breezy spots.

Summer

Once established, Palmer's penstemon shifts into a low-maintenance summer mode, tolerating El Paso's heat well as long as the soil stays on the dry side.

• Cut back watering to once or twice a month through summer for established plants. More frequent water in heavy soil increases the risk of root disease.
• Cut spent flower stalks back after bloom finishes to keep the plant tidy and encourage new basal growth.
• Expect little to no bloom during the hottest weeks. That is normal, not a sign of a problem.
• Leave some seed heads on the plant if you want volunteers next year, since this short-lived species relies on reseeding to persist in a bed.