Sometimes you can just see why a particular variety has stood the test of time. Dahlia ‘Thomas A. Edison’ is a case in point — this heirloom favourite, first bred in the U.S. and introduced back in 1929, deserves every bit of its acclaim, with its massive dinnerplate heads in handsome, deep magenta purple. This conspicuous shade is consistent across each huge flowerhead — ever so slightly lighter at the edges – with involute petals providing true depth of colour in the centre.