Geranium, Cranesbill, Hardy Geranium, Knotted Cranesbill, Pyrenees Geranium 'Tanya Rendall'

According to the patent application, the female parent is G. x antipodeum 'Black Ice', and the pollen parent is a G. x oxonianum.
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From the parentage, I'd expect it to be be as hardy and hot-summer-tolerant as G. x 'Orkney Cherry', which has similar parentage, and does well through Z5 in eastern N. America.

Unlike most hardy geraniums, which are generally adaptable to a wide range of soils, I'd expect this one to prefer soils with an alkaline or neutral pH.

Geranium 'Tanya Rendall' was bred in the Orkney Islands by Richard Rendall and named after his daughter. It is a compact form, smothered...Read More with 1.5cm intensely coloured magenta flowers with a white eye bleeding into the petal. The petals are notched and distinctly separate. Foliage is reddish when young, turning dark olive green. This is an ultra hardy plant, having been exposed to harsh Orkney winters. Suitable for the front of border, rockery or on walls and pest and disease resistant. Geranium 'Tanya Rendall' is flowering from May until first frost.