Weedy Wednesday: Medicago lupulina

Cathy of Words and Herbs periodically publishes posts under her Wild & Weedy Wednesday meme during the summer season.  (Here's her last post on the wildflower known as ragged robin.)  As I got caught up addressing my struggle with a relatively handsome but excessively vigorous weed, I decided it was an optimal time for me to share my experience with Medicago lupulina, known by a variety of common names including black medick, hop clover, lesser trefoil, and nonesuch.  Curious about the "nonesuch" name in particular, I looked for an explanation and discovered that it was regarded as a superior plant (i.e., "without equal") offering high nutritional value for feeding livestock.

I'm sure I've seen it before but, if so, I can't recall it ever taking over a particular area of my garden as it has this year.  I yanked out a mass of it when I initially discovered it a month ago, only to find it appeared to have redoubled its effort to achieve world domination last week.

It's said to grow up to 2 feet in height but it was less than a foot tall year; however, it covered an area 5-6 feet in diameter here

Spreading via creeping stems to form mats, its tiny leaves resemble those of clover, although what stood out to me were its distinctive but equally tiny yellow flowers.  It reportedly thrives in dry soil (bingo!) and full sun, although the area here lies in partial shade.

Complicating matters, it was growing alongside and tumbling over Erigeron karvinskianus (aka Mexican or Santa Barbara daisy), which is virtually a weed here too

This is a closer look at the leaves and flowers.  The plant is in the legume/clover family and, like other plants in that family, can be helpful in fixing nitrogen in the soil.

The plant's native to Europe and temperate areas of Asia but it's a well known weed in lawn areas in the US.  The area most densely covered by the weed is in one formerly covered by lawn, which we removed in or around 2016 but perhaps that's where it gained its initial foothold.  I'm not sure what prompted it run amok this year but then a lot of weeds seem to be running roughshod through my garden this year despite our low rainfall.

The plant's effort to encompass this Phormium 'Maori Queen' forced my hand

Unfortunately, not only do its stems creep but it also develops a long taproot, making it difficult to remove.  I did my best to uncover the Phormium shown above and the other plants in the same bed.

Whether I got out all those tap roots is questionable but it looks clear for the moment.  Almost all the Erigeron went too as the 2 plants were intertwined.

Much of the area between and surrounding the flagstones had been planted with creeping thyme but I tried to weed out stems that crept into the thyme while leaving it in place where I could

I'm by no means done with its removal.

The areas in more sun between the flagstones still contain a large number of taproots that don't want to let go.  I may have to remove the stones to get at those roots.

Medicago has also taken hold in parts of my cutting garden in the gravel paths adjacent to the base of the raised planters.  It's nominally easier to pull out there, probably because the soil is moister.  It's generally described as a summer annual so whatever I don't manage to remove may die out at the end of the season but I'll continue my effort to eradicate what I can.  The plant's said to have medicinal properties as an antibacterial and anti-inflammatory but these claims aren't well substantiated.  Historically, it was also reputed to have been used as a laxative and an aid in blood clotting and resolving digestive issues but I don't recommend experimenting with it even if it's not considered toxic!

Do you have any experience with this weed?  If so, what approaches did you use in removing it?

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