Magnolia liliflora nigra x spengeri diva 'Spectrum'

Magnolia 'Spectrum' is one of the great red-purple magnolias, a large deciduous tree that covers itself in spring with huge, tulip-shaped flowers of deep reddish-purple. Each bloom can span ten to twelve inches, richly colored outside and paler pinkish-white within, opening from fat, purple-pink buds in mid to late spring, later than the frost-prone saucer magnolias and all the safer for it.

The tree comes from the celebrated magnolia breeding program at the United States National Arboretum, a deliberate cross of two Asian species, Magnolia liliiflora 'Nigra' and Magnolia sprengeri 'Diva'. 'Spectrum' is the sister seedling of the equally famous 'Galaxy', and the two are often grown as a pair; where 'Galaxy' is narrow and upright, 'Spectrum' spreads a little wider into a broad, conical head of thirty to forty feet. The genus Magnolia honors Pierre Magnol, the French botanist of Montpellier.

The flowering is the whole point. Set against bare branches, the enormous purple goblets are unmissable, lightly fragrant, and carried in generous numbers even on a fairly young tree. The later bloom time, inherited from the Asian parents, usually lifts the display clear of the last hard frosts, so the flowers open clean rather than browned, a real advantage over the early-blooming tulip magnolias.

Give 'Spectrum' an open but sheltered site with deep, rich, well-drained soil that stays evenly moist, and room for the broad crown to develop. Site the tree as a spring specimen where the flowers can be admired from a distance, ideally against evergreens or a clear sky that sets off the red-purple. Full sun brings the heaviest bloom. Plant this National Arboretum classic for a spring show that arrives just late enough to be reliable.