A surprise driving away from London’s Heathrow airport the other day. There’s a huge intersection where the road from Heathrow joins the M25, London’s 117 mile, six and eight and ten lane, orbital motorway. At one point there’s a traffic light and there, by the side of the road, spilling out through the fence, were three huge euphorbia plants, Euphorbia characias.

So, I drove - carefully - all the way round again, extracting my camera from the bag on the seat alongside me as I went. I manoevred across into the lane alongside the euphorbias and – the lights had changed. I came to a halt in just the right spot, snapped three quick pictures out of the window before the lights changed to green, and I was on my way home. One picture was sharp –ish (above, click to enlarge).

This is not a British native plant, it’s from the Mediterranean, but I’ve always grown it. But on a roundabout on the M25? There are no gardens for miles. I bet some mischievous passing gardener threw a few seeds out of the car window. I'll be keeping an eye on them from now on.