William 's grandfather , also William McNab , was foreman at the Royal Botanic Gardens , Kew .
William 's father , James , was a horticulturist and principal gardener from 1849 of the Royal Botanic Garden Edinburgh .
William 's grandfather , also William   , was foreman at the Royal Botanic Gardens , Kew .
William 's father , James , was a horticulturist and principal gardener from 1849 of the Royal Botanic Garden Edinburgh .