Douglas originally trained in tropical plants and nursery work locally, but after obtaining degrees in horticulture and botany at UBC, pursued a career in public horticulture and teaching. Douglas is currently an Associate Director at UBC Botanical Garden, where he's been Curator of Collections since 2000. Douglas is active in the Vancouver Cherry Blossom Festival and together with volunteers from the Festival, wrote the handbook Ornamental Cherries in Vancouver. He also authored the mobile app entitled Vancouver Trees and is now working to complete a volume on Vancouver's shrubs.