Brief update. The tree pit is Morrison's carpark is a washout. Too much foliage from the untrimmed Magnolia? Erratic weather? Anyway, the sole survivor is the Euphorbia. All 3 of the nasturtium seeds I planted in the bare patches that some neighbours call 'gardens' have been 'weeded' out. No, nothing has replaced them. However, 2 more have spouted. One is in the raised bed next to the job centre on Camberwell Green - in which the cornflowers, golden rod and daisies are also surviving. The other is the brilliant though vulnerable location of the tree pit immediately outside The Tiger. This is a big pit and would be ideal were it not for the regular digging up of the pavement and the habit of dumping rubbish bags against the tree. The seedling is inside the mesh around the tree. I will label it and hope.