Dave's Garden. Search the extensive PlantFiles database.
Links for Crataegus × lavallei
Denver Botanic Gardens - Description, native range, and cultural requirements. (zone 4b) (8 photos)
Missouri Botanical Garden - Plantfinder page for one of the plants growing at the garden, with usually one or more photos, horticultural information, and noteworthy characteristics. (zone 4-7) (2 photos)