Best magnolia cultivars by region

The magnolia genus (*Magnolia*) spans deciduous and evergreen trees and shrubs from temperate North America, Asia, and Central America. Per NC State Extension, it contains over 200 species plus hundreds of cultivars. For North American gardeners, the most relevant species sort into three groups:.

The magnolia genus (Magnolia) spans deciduous and evergreen trees and shrubs from temperate North America, Asia, and Central America. Per NC State Extension, it contains over 200 species plus hundreds of cultivars. For North American gardeners, the most relevant species sort into three groups: the iconic spring-blooming deciduous magnolias (including M. stellata, M. × soulangeana, and the 'Little Girl' hybrids), the summer-blooming M. grandiflora and its cultivars for southern landscapes, and the native M. virginiana (sweetbay magnolia) for broad adaptation.

I don't grow magnolia at my place in Melville, Long Island, though neighbors have M. × soulangeana that bloom magnificently in late April — and get hit by late frost at least two years in five. That late-frost vulnerability is the defining selection pressure for this genus in the Northeast.

Northern gardens (zones 4—6)

Magnolia stellata (Star magnolia)

Magnolia stellata is native to Japan, hardy in zones 4—8, and blooms the earliest of commonly grown magnolias — typically late March to early April in zone 6 — which makes it also the most vulnerable to frost damage, per Missouri Botanical Garden. The multi-petaled (12—18 tepals) white flowers are held on a large shrub or small tree, 15—20 feet at maturity.

Best cultivars for the North:

• 'Royal Star' — most cold-hardy selection; blooms slightly later (by about 1 week) than the species, reducing frost risk; per UMN Extension, rated zone 4b; white double flowers
• 'Centennial' — larger flowers (up to 5 in.) than the species; white; zone 4; 20 ft
• 'Waterlily' — pink buds opening to white flowers; zone 5; slightly later bloom than 'Royal Star'

'Little Girl' hybrids (US National Arboretum series)

Developed at the US National Arboretum in the 1950s—70s by crossing M. liliiflora 'Nigra' × M. stellata 'Rosea', the 'Little Girl' series blooms 2—4 weeks later than M. × soulangeana, significantly reducing late-frost flower bud damage in zones 4—6. Per Penn State Extension, these are among the most reliable late-frost avoiders for northern gardeners.

The named cultivars (girls' names):

• 'Ann' — deep reddish-purple buds, lighter purple inside; 8—10 ft; a standard selection and one of the most cold-hardy (zone 4—8)
• 'Betty' — large flowers, purple-red outside, white inside; 10—15 ft; among the best in the series for flower size
• 'Jane' — fragrant; red-purple flowers; 10—15 ft; zone 4—8; late bloom timing helps most in zone 5—6
• 'Susan' — dark purple-red, twisted tepals; 10—15 ft; consistent performer in Penn State trials
• 'Pinkie' — pale pink, slightly less vivid than the others; sometimes available from specialty nurseries