This showed up this year. It's about 70cm tall, the flowers are only about 2.5 cm wide. Stems are round, hirsute. Leaves appear to be hastate with a crenate margin. The flowers have four off-white petals with red veins and six... structures... in the centre.
Wow. Do you guys get extra points for how quickly you come up with the right answer? Yes, that certainly looks right. Common name "garden rocket" or "rocket-salad". It's a Brassica, although the flower does not suggest that. It's edible. It's invasive. Pull it and eat it. Thank you togata57.
This looks just like what's labeled as Arugula Selvatica on the seed packets that I buy. I assume that it's the same species, also called wild Arugula.
