Plant of the Month

Plant of the Month: June 2020

Marsh Bedstraw

Galium palustre L. 1735, non M. Bieb. 1808, Pourr. ex Wilk. & Lange 1868

RUBIACEÆ; Madder Family

Marsh Bedstraw is a low, inconspicuous, perennial plant of mucky soil, such as in marshes, swamps, wet ditches, and lake margins. It grows around the northern hemisphere in suitable places, from North America to N Africa & Eurasia to the Arctic. Companion plants include horsetails, skunk cabbages, lady fern, water celery, buttercups and sedges.

Somehow, I failed to include it in my book Wild Plants of Greater Seattle. So this little article makes amends. On pages 280 and 281 (of the second edition) I describe and illustrate four related Galium species.

I learned about the plant this month, visiting the garden of famous gardener Ciscoe Morris, in Seattle. Ciscoe mentioned that he has battled a weedy Galium for years, but has been unable to get rid of it or identify it. I took a few stems home with me, put them in a pail of water, studied them, and identified the species as Marsh Bedstraw.

Based on its presence in Ciscoe's garden, plus herbarium collections from Lake Ballinger and Panther Lake, Marsh Bedstraw is a rare naturalized species of greater Seattle. I guess its small size and lack of glamor have made few botanists collect herbarium specimens of it. Collections exist from various places in southern British Columbia, Washington and Oregon. It likely is more common than the herbarium record suggests.

Its stems are square rather than round in cross section, with minute little barbs. Leaves are borne in whorls of 4 to 6. The tiny flowers are only 2.5 to 4.5 millimeters wide, pure white, and fragrant. They are borne in clusters of as many as 9.

You may know the garden plant Sweet Woodruff (Galium odoratum), a species that is far more robust and noticeable than Marsh Bedstraw. It is the best known, most cultivated of over 600 Galium species. Its flowers and foliage smell sweet. But it can become weedy and be difficult to control.

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