Not much to see at the moment but this is a very vigorous plant: Rosebay Willowherb (Epilobium angustifolium). On the whole it's too vigorous for gardens unless very large and wild but I have a bed at the front of the house where the spread would be contained.

 The simplest form of propagation is root division, as above. There is a large patch of Rosebay Willowherb at the music school so I dug around a stem and grubbed out a section of rooty rhizome with it. It was once commonplace to sell plants fresh out of the ground bare root before growing stock in plastic pots became the norm. It still happens, I recently purchased five of Purple Loosestrife from Shipton Bulbs which were dispatched bare root. They looked rather like a collection of twigs but they too are vigorous.

 Epilobium angustifolium is said to be a native of this island but then again it's also a North American species; for example I saw some growing by a spring in Northern California when I was hiking on the Pacific Crest Trail. Old botanical records note that it was sparse in the UK which is curious since it's so prolific now.

 My father tells me that it grew all over London after the war colonising bomb sites and derelict land. Rosebay Willowherb is known to be a pioneer plant of burned ground hence it is sometimes referred to as Fireweed. When in flower in summer it is fiery indeed...