The landscapes, life-zones and gardens of Colorado’s Southern Rocky Mountains

Chris Moore

The trip began in Denver, which lies at the eastern base of the Southern Rocky Mountains. A fantastic selection of tours at Denver Botanic Gardens (DBG) from Mike Kintgen, Mike Bone, Kevin Philip Williams and Michael Guidi made me feel right at home, and provided a comprehensive introduction to the diversity of floristic life zones around Denver. The garden has a strong focus on promoting native plants, as well as those from further afield equally suited to Denver’s semi-arid climate. Such plants are trialled and selected for beauty and resilience by the non-profit organisation, Plant Select, which DBG plays an important role in. The rock garden, steppe garden, and public plantings on Josephine Street were impressive. The latter highlighted the untapped potential that we have in our own urban environments for robust and beautiful plantscapes.

Arenaria hookeri at Pawnee Buttes

On the recommendation of the staff at DBG, I travelled north east to the Pawnee National Grassland to botanise along the Pawnee Buttes Trail. The track runs through relic areas of short and mixed grassland prairie, as well as clay and silt barrens. The landscape is harsh; hot, dry and windy. It was a pleasure to see Bouteloua gracilis in its natural habitat, deep rooted and anchoring the soil in place, flowering alongside patches of Opuntia polyacantha. Thousands of blooming Yucca glauca dotted hillsides running down into the dried creek. Here, plants grew out of bare rock, their taproots accessing deep moisture. Huge clumps of Arenaria hookeri tumbled down from the steep sides, covered in icy white flowers.

Oenothera and Astragalus growing in the barrens at Pawnee Buttes

One of the great draws of Colorado is its accessibility to a range of different altitudes and aspects. Two of its great mountains – Mount Evans and Pikes Peak – have paved roads to their summits, sitting at over 14,000 feet. Unfortunately, due to a particularly heavy winter snowfall and resulting late snowmelt, much of the botanical appeal of Mount Evans was lying dormant under the snow. The first alpines were beginning to bloom in patches of snowmelt, but the real show wouldn’t begin for another fortnight. Higher up, at Summit Lake, swathes of Caltha leptosepala bejewelled the damp patches, and on the roadside the crimson heads of Rhodolia integrifolia were emerging. Two weeks later, on Pikes Peak, I was rewarded with a much better display, including Primula angustifolia – one of the great American alpine plants. Of particular interest were the granite outcrops that hosted a number of interesting plants, including Aquilegia saximontana and the endemic Telesonix jamesii.

Aquilegia saximontana nestled in a granite outcrop on Pikes Peak

Other highlights included a visit to Betty Ford Alpine Gardens, the cutting edge Rocky Mountain Biological Laboratory in Gothic, alpine hunting on the Hoosier Ridge, the sagebrush communities of the intermountain parks, and the pinyon-juniper woodlands on the western slope. I wish I had more pages to described them.

I am thankful to the Kew Guild, Hardy Plant Society, RHS, and Bentham-Moxon Trust for making this trip possible, and to everyone I met in Colorado for making me feel so at home and imparting so much of your hard earned knowledge. Most importantly, thank you to Emilee Shaw for your excellent company and driving me everywhere; I don’t know what I would’ve done without you.

Photos copyright Chris Moore.

The most beautifully designed and crafted crevice planter at Denver Botanic Gardens, Steppe Garden. 

The planting at Josephine Street inspired by Hitchmough's Sowing Beauty offers a blueprint for a low maintenance and dynamic urban planting.