Galium aparine, or
Bedstraw grows easily from seed in oak woodlands with no care. If
there isn't much plant material growing and there isn't much mulch the
weeds will start up. I use this annual Bedstraw as a great solution
to that problem, Galium aparine rapidly fill space and dies back at the
end of Spring. I selectively weed to make space for Bedstraw any
time I see it volunteer in a garden, and I take up a few seeds and
sprinkle them into other gardens to get them going there too. Galium
aparine grows to a foot tall, if it finds something to clamber up or over,
and spreads to as much as 2-3 feet. The foliage of Galium aparine
becomes increasingly fragrant as it dries. Galium aparine is native to much
of the US, including almost every county in California and through much of
Eurasia.
High resolution images
of Galium aparine are available.