Upon a bit more study, there are apparently other mustard-family plants that look like shepherd's purse - but they will only have one seed per side of the seedpods, shepherd's purse will have many. Now I need to go check my local variety, and see what I've really got...
closely related to shephard's purse but the seed pods are slightly differently shaped. i think that at least for the medicinal uses they are interchangeable - it is used to stop bleeding both externally as a poultice and internally as a tincture (which smells HORRIBLE!!!)
Location: Poplar Hill, Ontario (near London) - Zone 6a
posted 6 years ago
I'm fairly sure this is indeed Field Pennycress - the notch in the circular seed pod is a field mark. In my region, Shepherd's Purse has a heart-shaped seed pod that's smaller. There are several other related small mustards, but I'm fairly confident with that ID - and to my knowledge, all mustards are edible (if not all good tasting) - though I'm happy to be corrected on that.
I like this plant. It loves disturbed soil, and if it's present, even if you mulch, you'll get a bit here and there. The leaves before it goes to seed have a nutty/mustardy taste in salads which I quite like. That taste gets stronger when they go to seed, but in my opinion is still okay. I'm sure you can use it as a cooked green, and can probably eat the tenderest part of the stem when it's growing quickly either raw or steamed. Flowerheads taste good to me too - though a bit strong flavoured. I've had people taste this and love it, and read descriptions that say it tastes awful. Try a small bit to make sure you like it.
In good conditions (full sun, various soil types) it gets very big, and produces many seed pods. In the past, I've gathered a bunch of big plants and hung them to dry, then gathered the seeds out of them. When ground, the dried seeds make a very nice seasoning a bit like black pepper (Pennycress is closely related to Peppergrass, as well as Shepherd's Purse). There's likely not much need to replant seed - it'll be back!
Of course - make sure you're confident with the ID yourself before consuming it.
i'd agree with the previous ID's but ive always reffered to it as poor mans pepper grass (botanically it is obviously not a grass but...) because from my understanding the dried seeds make a decent substitute for black pepper