Have you ever marveled at a vigorous plant thriving in the narrow gap between two rocks? Or wrestled with a weed that stubbornly grows through the crack in a sidewalk? The tenacity of plants to grow, and sometimes prefer, these tight settings is the premise behind crevice gardening, a form of rock gardening which is gaining in popularity.
To learn more about crevice gardens, a group of Denver County Master Gardeners recently toured the Community Heroes Crevice Garden (CHCG) located at the Apex Simms Street Recreation Center in Arvada. CHCG was designed and built by Kenton Seth and his team in 2014-2015. It is one of the largest crevice gardens in the world, spanning over 1,000 square feet, built with 60 tons of Dakota sandstone from southern Colorado, 14 tons of sand and 20 tons of gravel.
Crevice gardens mimic mountain terrain through the use of flat stones which are laid vertically and buried deeply to create narrow gaps. The entire rock structure is “engineered” for stability with the care that a seasoned mason builds a dry stacked retaining wall. The stones keep the plants cool during the hottest part of the day and create various microsystems depending on the garden’s orientation. The gaps are filled with a porous, sandy planting mixture which is layered to promote optimum drainage and deep root development.
Specimens are planted “bareroot”, meaning the original potting medium is removed prior to planting. Roots are then gingerly tucked in the crevices. Once plants are established, CHCG is watered by overhead irrigation every two weeks or less. Crevice gardens generally showcase xeric plants, such as delosperma, hens and chicks, species tulips and manzanita, to name a few. Trees and tall plants which would shade the garden are discouraged. The majority of plants at CHCG are from the dry, cold grasslands of the Steppe regions. A complete list of the plants used at CHCG and directions for starting a crevice garden can be found here.
CHCG is a young, ambitious public garden. It’s very much a living laboratory (but then, aren’t all gardens?). It will be interesting to visit it periodically to see its development and seasonal changes. We are fortunate to have several established crevice gardens in Colorado including at the Denver Botanic Gardens (within the Alpine, Mordecai and Steppe gardens) and Vail’s Betty Ford Alpine Gardens (home of the International Alpine Crevice Garden).
If you are interested in trying crevice gardening, Kenton offered that growing plants between a few vertical, closely set rocks in the ground or in a stone trough is an easy and fun way to get started!
Photos courtesy of Kenton Seth
Written by Linda McDonnell, a Denver County Master Gardener.