Easy Groundcover: Monkey Flower

Credit: Richard Hebda

Monkey flower—relative of foxglove and snapdragon—is an easy-to-grow and colourful groundcover for moist sites

The figwort family (Scrophulariaceae) is widely known as a source of super ornamentals such as snapdragons and foxgloves. This clan is well represented in British Columbia’s native flora too, including several penstemon species and fascinating speedwells (Veronica species). Monkey flowers (Mimulus species) also belong in this family and one species in particular, yellow or seep monkey-flower (Mimulus guttatus), occurs in a wide range of climates and makes an excellent garden ornamental.
 

Sizing up monkey flower

Monkey flower varies widely in form, some growing as a mat-forming mass scarcely 10 cm (4 in.) high, while others rise tall on substantial stems to 80 cm (32 in.) high.

Numerous oppositely arranged oval leaves are spaced along the stems. They range from 1 to 10 cm (0.4 to 4 in.) long, have a generally yellowish-green tinge and bear large irregular teeth along the margin.

Blossoms form clusters at the tops of stems, appearing to nearly smother the plant. Each 1- to 4-cm long (0.4 to 1.5 in.) flower consists of a bright-yellow funnel of five fused petals, marked with bright-maroon spots in the throat. The throat is also very hairy especially on the three-lobed lower lip. Flowering time ranges widely. On lowland Vancouver Island flowering sheets appear on rocky sites as early as April. In interior B.C. where the winters are long, flowers may be encountered as late as mid summer. 
 

Where to find monkey flower

The natural range of yellow monkey flower is remarkably wide. You can encounter it throughout B.C. from sea level to mid elevations. Outside of the province the range extends from Alaska to Mexico and there are even scattered populations in eastern North America. Natural habitats tend to be moist for at least part of the year. On bedrock surfaces, typical situations include wet ledges and seeping rock faces as well as crevices. Other natural habitats include gravel bars, stream sides, springs, and damp clearings. In the Victoria area, robust individuals appear in local ditches after the water has dried out.  

Monkey flower can be easily grown via two methods, seeds or rooted stem fragments and divisions. Sow seeds in fall or spring on a damp peat soil surface where they will germinate readily. Seeds can be collected in the wild and are also readily available through numerous native-plant seed suppliers. Alternatively divide a sprawling clump into rooted stem segments in spring or fall, and grow them on in a moist loose soil until they are well established, then set out in the garden.

The choice of garden uses is wide, including sunny to semi-shaded sites. Plant them in moist places such as along streams or at pond edges. They can also be used at the front of a perennial bed as long as you water them frequently. Even a moist rock garden will support an attractive patch. These monkey flowers are short-lived perennials in mild climates but they self-seed so reliably in suitable sites that you can depend on them coming back year after year. In Great Britain yellow monkey flower has even become an invasive species.

Monkey flowers were apparently not used by B.C. First Peoples. In the western U.S., Aboriginal people ate fresh or boiled leaves, drank a tea for stomach aches and made a poultice for wounds.
So if you are looking for an easy-to-grow colourful groundcover for moist sites, try yellow monkey flower. Hardy throughout most of the province, this bright-yellow wildflower deserves to be much better known.

Mimulus guttatus (yellow or seep monkey-flower) is hardy to zone 6.
 

An expert on native plants, Richard Hebda is curator of Botany and Earth History at the Royal British Columbia Museum in Victoria.