Sweet Woodruff, Galium odoratum, Perennial Groundcover for Shade

Looking for a groundcover plant that’s suited for shade gardens but not sure if the bold periwinkle or wandering goutweed would be the right selection? Like the idea of using a perennial that’s been called delicate, starry, handsome, delightful, and sweet? Then sweet woodruff is definitely the plant of choice. Not only is it perfect for shady woodland gardens, it needs shade, so there’s little chance it will wander beyond its bounds into sunny areas.

Starry Flowers and Scented Leaves Adorn Sweet Woodruff

Sweet woodruff, Galium odoratum (or synonym, Asperula odorata) is a low-growing carpeting plant which reaches a height of four to nine inches. It blooms in late springtime with tiny white flowers which give a sprinkle-of-snow-effect. Its leaves are narrow and arranged in whorls, just like umbrella spokes. They are evergreen where winters are mild; in colder areas the leaves survive the winter but fade away in the spring when replaced with new fresh growth.

The little star-like flowers have a pleasant scent, but it’s the leaves of sweet woodruff which are prized for their fragrance. The term odoratum in its name comes from this quality. According to Perennials for Shade: Easy Plants for More Beautiful Gardens, when dried and crushed, the leaves release coumarin, a chemical used in the perfume industry to help fix fragrances. This sweet scent also made this plant a favorite for stuffing pillows and mattresses, along with its cousin, Galium verum, lady’s bedstraw.

Easy to propagate, sweet woodruff just needs to be divided at any time during the growing season for a supply of new plants. By digging up one clump from an established plant, the gardener can get many small rooted plantlets. When these are planted out about one foot apart they quickly form a new groundcover. To enjoy this little plant from a closer vantage point, the gardener might also pot up sweet woodruff into patio pots for summer enjoyment.

Moist Shade is the Key for Growing Sweet Woodruff

In Perennials for Shade ‘bewitching’ sweet woodruff is praised as more than just a useful groundcover: ‚”A shade garden without sweet woodruff is hardly worth contemplating. It will fit anywhere and everywhere, with wildflowers, with cultivated woodland treasures, or as a ground cover under shrubs and trees.” As long as the ‘everywhere’ includes evenly moist soil and partial shade to full shade, sweet woodruff will thrive.

Why Choose Sweet Woodruff as a Groundcover Plant for Shade?

This small spreading plant with the lacy flowers is a perfect fit for shady woodland gardens. Easy, lovely, and somewhat refined (as groundcovers go), sweet woodruff gives the gardener great benefits:

• With its semi-evergreen leaves it looks attractive in any season.
• It provides a lovely show of starry white blooms in springtime.
• Loves shade, and prefers a woodland setting.
• It creeps rapidly over the shade garden, but is easily controlled.
• Complements other woodland plants and can be interplanted with spring bulbs.
• Withstands heavy root competition from large trees.
• Requires little care, not even cutting back.
• Bonus: Fragrant dried leaves can be used in pot pourri, or in wine.

Is Sweet Woodruff, Galium odoratum, an Invasive Species?

Opinions are divided on whether sweet woodruff should be classified as an invasive species or not. All perennial groundcovers have aggressive tendencies, i.e., they are invasive by nature, spreading rapidly and more-or-less widely from where they are planted. It’s not surprising then that they are often labelled as ‘invasive species.’ Bugleweed, goutweed, and periwinkle all have that designation.

Galium odoratum is native to Europe and Asia and so doesn’t form part of the native plant ecosystem of North America. According to the Canadian Wildlife Federation, sweet woodruff has the potential to become invasive. But this plant isn’t found on the US Department of Agriculture Invasive Species list.

Toronto and Region Conservation, however, places sweet woodruff on its list of invasive non-native species found in Toronto gardens and parks. It advises removal of ‘these invaders.’ Also on the list are silver birch, Norway maple, lily-of-the-valley, English ivy, and of course the groundcovers goutweed and periwinkle.

But garden writer Larry Hodgson doesn’t see this little plant as a threat to native species. In Making the Most of Shade he advises its use in woodland gardens, either combining it with ferns or other woodlanders, ‚”Or try liberating it in a forested area whose undergrowth seems a bit colorless, and its spring green foliage will soon add a lot of pizzazz to the effect.”

Sweet Woodruff is One of the Top Shade Garden Groundcovers

Aptly named sweet woodruff, with twinkling flowers and fresh green foliage, gives a lovely display from spring through autumn. This diminutive and delicate-seeming plant is one of the best carpeting groundcovers available for the shady woodland garden.

To learn more about other groundcovers for shade, see these articles:

Bugleweed, Ajuga reptans, Groundcover for Shady Woodland Gardens

Periwinkle, Vinca minor, Perennial Groundcover for Shady Gardens

Goutweed, Bishop’s Weed, Groundcover for Shady Woodland Gardens

References:

Hodgson, Larry, Making the Most of Shade: How to Plan, Plant, and Grow a Fabulous Garden that Lightens up the Shadows, Emmaus, PA: Rodale, 2005.

Taylor’s 50 Best, Frances Tenenbaum, Editor, Perennials for Shade: Easy Plants for More Beautiful Gardens, Boston: Houghton Mifflin Company, 1999.

Canadian Wildlife Federation Invasive Species Encyclopedia (accessed July 14, 2010)

Toronto and Region Conservation Invasive Plant List (accessed July 14, 2010)