Rocky Mountain states: Unthirsty color in Denver

Showy plants need not be thirsty plants. That point is made beautifully by the Roads Watersmart Garden within Denver Botanic Gardens. Despite its sunny exposure, last year the border needed watering only seven times between the end of May and the end of October.

Dan Johnson, curator of native plant collections, maintains the border using plants from dry climates all over the world. He incorporated Colorado and Southwestern natives like agave and cactus as well as Mediterranean plants.  He also planted scarlet trumpet honeysuckle, yellow-flowered Sedum ‘Blue Spruce’, Osteospermum ‘Purple Mountain’, white snow-in-summer, spiky purple Salvia x sylvestris ‘May Night’, and star of Persia (Allium christophii).

Composed mainly of perennials, the border also holds a number of species tulips whose bulbs bloom during the cool, moist spring weather, then go dormant during the hot, dry summer. In addition, selected self-sowing annuals and biennials ― including California poppies, clary sage, and sunflowers ― are allowed to reseed.

Part of the secret of the border’s success is soil composition and contour. Compost and fine gravel were mixed in to promote drainage. The border’s contour is raised at the center so water won’t pool near the crowns of plants.