Mustard time!

Photo by Marty Horowitz 1/19/2015

Spring Azure on London Rocket (Sisymbrium irio). London Rocket is a non-native (but hey, so am I); but it doesn't appear to be invasive (and downright nasty) in the same sense as, say, Giant Reed (Arundo donax) or Buffelgrass (Pennisetum ciliare). Moreover, it's blooming now and looks to be a nectar plant for Spring Azures! (Which is more than one can say about Giant Reed and Buffelgrass.)

London Rocket in the Mustard family and, like many mustards, is edible. The leaves make a nice addition to mixed salad greens.

Grows in disturbed soil - you'll see it all over in Tucson along road sides and on construction sites. London Rocket gets its common name because it grew in abundance after the Great Fire of London in 1666. (Talk about disturbed soil.)