Bark dust is not a groundcover. It is a type of mulch. Its purpose is to deter weeds and reduce evaporation. It is temporary until new plants cover the soil. Groundcover plants eventually knit and cover the bare earth holding moisture for themselves and the planting layers above them.
Layered and dense plantings provide habitat, visual interest and shade. If you prefer a more sparse planting arrangement keep it simple with 2 or 3 shrub varieties, well spaced, but with a dense groundcover. Dense plantings are beneficial to the soil, their roots breaking up clay and encouraging beneficial microbial activity in the soil.
Just as medical science has uncovered the good bacteria in our bodies, soil scientists have discovered wondrous activity underfoot. Soil mycorrhiza is a fungus that has a symbiotic relationship with plant roots-it is an important part of soil and plant life. A soil wasteland of bark dust with little in the way of plant life is basically dead soil especially if it has been tilled, scraped or re-graded. Tilling exposes soil mycorrhiza to air and heat destroying the soil’s microbial life.
It can take years to renew damaged soil but it can be done with the proper compost and plants. Letting leaves lie can help build better soil. Ground beetles and sow bugs feed on dead leaves breaking them down into smaller particles that enrich the soil. Salamanders can slink unseen under damp leaves. Fallen leaves provide cover for nesting bumblebees.
As with the vast unknown under our oceans and in our heavens, beneath our feet there is a whole other world.
Readings:
‘The Soil Will Save Us” by Kristin Ohlson
“The Know Maintenance Perennial Garden” by Roy Diblik
Donna Giguere Landscape Design 