Crevice Garden Growth: Fall Install 2024 – First Season of Growth 2025

First Season Review, by Michelle Williams, Idaho Firewise Garden Assistant

What a joy it was following the seasonal outcomes of our newly introduced plants stretching for establishment in the crevice garden environment created back in fall 2024. There were some big hits that received “oohs and awes” during garden tours. There were also some disappointing misses as a few plants did not make it past the first winter or summer. Overall, plant successes outweighed any failures.

Planting in the fall may be tricky for some plants, especially succulent types from warmer southern regions. Two of these different types of plants were introduced during the initial install and were the cause of great excitement. As spring rolled around, we found that the prized Agave parryi, century plant, and the Bulbine abyssinica, bush bulbine, did not make it through the winter. We may try again but if we do, the species will be planted during the spring gardening season.

Spring 2025 plant additions to highlight are Scutellaria suffrutescens (cherry skullcap), Eriogonum heracleoides (parsnip flower buckwheat), Penstemon virens (blue mist penstemon), Osteospermum (Mandy™ sun daisy), and Erigeron formosissimus (Rambler ™ mountain fleabane). The cherry skullcap bloomed very well and for a long duration in the late summer and fall. This plant was given a lot of attention by garden-goers.

Another observation made over the growing season was that the crevices receiving overhead irrigation had better plant growth. Naturally formed crevice gardens only receive water from overhead sources. Once plant establishment is made, the idea of rainfall only may be sufficient to support the plants contained within. Another note for overhead watering considerations is to avoid plants that are more susceptible to powdery mildew. Salvia nemorosa (sylvestris), ‘Marcus’ dwarf sage, struggled with powdery mildew during the growing season.

The horticultural staff at the Idaho Firewise Garden are looking forward to the 2026 gardening season and seeing the plants in the crevice garden really take off!