It is, of course, poisonous, the seeds especially so (although the drug used medically is extracted from the leaves), and one of its old country names is Dead Man's Bells. I have grown several species over the years and one of them, Digitalis lutea, seeded so freely in Byfield that it almost attained the status of a weed. I now confine myself to our native foxglove, not only because it is arguably the loveliest of them all, but it is a very good bee-plant too.
Digitalis purpurea in our garden in Daventry, showing the
freckles on the lower part of the corolla tube. 10 June, 2016
Here in Northamptonshire it is very local as a truly wild plant, being another of those species referred to by G. Claridge Druce in his 1930 flora of the county as rare and ericetal, i.e growing - like Erica (heather) - in acid soils (it flourishes at the summit of Borough Hill, here in Daventry). Gardeners have learned however that, given otherwise good care, it will tolerate a little lime. Indeed it is now frequent on waste ground around villages as a garden escape.
I was surprised, given the dearth of acid soils in the east of Northants, that John Clare mentions it:
Though the thickets bushy dell
Tempts me to the Foxglove's bell.