plant identification

(Question)

Do you know the name of this plant. It is in a container on my south-west balcony in Toronto which gets lots of sun and wind. It just popped up and none of the seeds that I planted look like this plant. I was using worm castings as fertilizer and regular potting soil.Thanks

IMG_0541

(Answer)

This plant is wild mustard Sinapis arvensis L. It is an annual weed. It is a member of the family Brassicaceae. This weed is usually found in disturbed places, along roadsides, fields, pastures, ditch banks, dry washes. Wild mustard can form dense patches that outcompete desirable plants.

Manual removal or cultivation before seeds develop can control populations. Physical removal is easiest during the seedling stage.