Dusky Crane's-bill 'Purpureum,' a Mourning Widow
'Purpureum' is a race of the Dusky Crane's-bill, G. phaeum var pupureum, a hardy geranium. There are many cultivars in addition to its wild races, known collectively as "Mourning Widows," for they are thought to have a more dour & dowager appearance than most crane's-bills.
Of the Mourning Widow varieties offered in nurseries, a sampling would include 'Lily Lovell' with mauve flowers, 'Samobor' with purple-chocolate flowers & spotted leaves, 'Album' & 'Stillingfleet Ghost' with white flowers, 'Hungaricum' with deep purple-red flowers, & 'Purpureum' which is a wild variant rather than a cultivar has the darkest purple to nearly black flowers of any geranium.
The whole group has in common the reflexed flowers, which make them stand-outs when compared to other hardy geraniums.
These are smallish flowers, about three-fourths inch wide, with the slightly ruffled purple-black or dark maroon petals turned backward, revealing a white center with mauve or yellow stamins. It flowers greatest May through July but with deadheading can be caused to persist until Autumn.Purpureum is a bit more compact & smaller than the species plant per se & most if its cultivars, but even at that is a substantial plant two feet high on average & occasionally taller. It stands somewhat upright rather than sprawling, a bit twiggy when young but forming a compact mound over time, the flower stems being somewhat chaotic with many branches & many flowers.
Its ideal condition is about half shade in moist well-drained soil, but Purpureum will do quite well in deep shade, & if never entirely drying out can survive in a lot more sun as well. In sun the leaves may develop a spotted "dusky" look which is natural & not indication of stress.
I had initially planted it in an afternoon-sunny location that got too dry. After the first photo above was taken in June, there was a droughty period, & the plant died back. I worried I'd killed it by not getting water to it enough, so I dug it out & moved it to a shadier spot that is watered very regularly.
Apparently I did this with short-term-memory only, as I entirely forgot I moved it. The following spring I kept watching the spot where it was first planted, hoping it would return, but there was no sign of it. I was just about ready to believe that for the first time in my life, I'd killed a hardy crane's-bill. Then in May I spied its blossoms peeping out from behind the Taiwan Juniper & suddenly I remembered that's where I'd moved it. The second photo was snapped in its present & far better location.