I would like to use a ground cover in a sunny part of my garden instead of cedar mulch. I would prefer a native plant. I have sweet woodruff cover in my shade garden. Will it grow in a sunnier spot? Other suggestions please? I am in the city of Toronto, climate zone 6 a, have loam with clay underneath, watered most days in summer. I have yellow and orange Austen roses, a yellow Itoh peony, a white rose of Sharon and some mauve rudbeckia in the sunny area where I would like to put the underplanting, as I am always weeding it. This sunny area abuts an area with a large native yellow senna bush, lily of the valley, forget-me-nots, etc., and tall blue spikes of flowers against a fence (name escapes me). Your help is appreciated.
Thank-you for contacting Toronto Master Gardeners with your question about mulch and groundcovers. While commercially available cedar mulch is preferable to leaving soil bare, a groundcover (a ‘living mulch’) is a great idea.
Sweet woodruff (Galium odoratum) does not do as well in sun as in shade. It can tend to scorch and die out in a full sun situation, leaving bare patches.
Bearberry (Arctostaphylos uva-ursi) could work well for you, especially if you prefer a native plant. As a member of the heather family, it prefers a sunny spot and tolerates dry conditions. It has the advantage of being evergreen so it provides some interest in winter. The spring flowers are white-pale pink and it develops small red berries that persist into winter. Here is a link to some general information about growing bearberry:
Some other, more popular examples that suit a sunny spot are creeping thymes (Thymus sp.) and stonecrops (Sedum sp.). These are tough, useful groundcovers that thrive in the sun. There are many cultivars to choose from. The thymes are native to the eastern Mediterranean and the Levant. Most creeping sedums are not native to North America either, but they are also great groundcover plants for sun with their distinctive, succulent foliage. The following articles give you some good options for thymes and sedums:
https://www.mountainvalleygrowers.com/groundcoverthymes.htm
https://www.finegardening.com/article/creeping-sedums
You will find a useful chart with various good groundcover choices which suit an Ontario garden at the following link:
https://guelph.ca/wp-content/uploads/HealthyLandscapes_Groundcovers_Lawn_Alternatives.pdf
Best of luck with your groundcover!