Citygarden’s plant palette emphasizes native Missouri trees, shrubs, grasses, groundcovers, and wildflowers.

When we made plant selections, we did so to ensure the long-term success of the plants, and to emphasize the four distinct seasons. Citygarden’s plant species and cultivars have a high urban and drought tolerance, and plants are located in specific locations based on their particular tolerances for varying degrees of sun, shade, wetness and/or dryness.

The garden is also home to 1,400 square feet of sedum-dominated green roof. More than 5,000 square feet spread over six rain gardens collects and infiltrates stormwater from two-thirds of the gardens’ surfaces. Despite extensive paved areas for pedestrian activity, nearly half the garden is designed to be permeable.

Trees planted within pavement zones have generous room for trunk and root growth. When we designed the garden, several strategies were employed to minimize compaction issues with these urban trees, including the use of a slab-and-pier construction system. In places where this system could not be used, structural soils are utilized.

In total, the garden includes 235 trees, comprising twenty different species. Of the 89 other species of plants, there are 1,170 shrubs, 4,194 perennials, native grasses and wildflowers, 8,000 bulbs, 12,726 groundcovers, and 32,000 square feet of lawn.

Photo courtesy of
Ross Mantle

Citygarden includes six separate rain gardens. Four small rain gardens along 9th Street filter site runoff, as well as runoff from 9th Street itself. Each individual block within the garden also contains a rain garden, which gathers site runoff through both surface flow and a series of underground pipes. These pipes are called a subsurface drainage system, which collects water from all over Citygarden and empties it into the rain gardens.

These six rain gardens, covering more than 5,000 square feet, collect and infiltrate stormwater from two-thirds of the site’s surfaces.

A rain garden is a planted depression in the ground that forms a “bioretention area” by collecting water runoff from impervious areas and storing it, which allows it to be filtered and slowly absorbed by the soil, rather than flowing

into storm drains. This helps prevent erosion, water pollution, and flooding.

Rain gardens also improve water quality through a nutrient removal, or “filtering” process, which takes place as the water comes in contact with the soil and roots of the surrounding trees, shrubs, and vegetation.

Both buildings in Citygarden, the maintenance structure for the Missouri Botanical Garden staff and their equipment, and the Terrace View, and a 100-seat café that overlooks the garden, employ green roof systems.

The 1,400 square feet of sedum-dominated green roof was designed to complement the look and feel of the rest of the garden, improve the views of the structures from the high-rise buildings that surround the site, and contribute to rainwater capture and conservation efforts used throughout Citygarden. Both green roofs use tray systems, which are effective for water retention.

Green roofs have many benefits, particularly in urban settings. The cooling effect of the green roof helps reduce the “Urban Heat Island Effect,” while decreasing the need for interior

building insulation. A green roof will also produce cleaner air by filtering the air moving across it. 

Depending on the type of foliage planted, one square meter of green roof can remove up to 4.4 pounds of airborne particulates from the air every year.

Additionally, because they are protected from regular foot traffic, green roofs can become home to plants that are easily damaged by walking, and to birds that nest on the ground. The soil on these green roofs also becomes a safer habitat for insects.