One of the most prized magnolias—and the tree of my childhood memory—is the saucer magnolia, Magnolia x soulangeana. This magnolia has the quintessential magnolia flower, 5 to 10 inches in diameter and made up of several large tepals. (The showy part of magnolia flowers is technically composed of tepals, not petals.) The fragrant flowers, usually pink or purple, appear in early spring before the leaves emerge and sit atop the branches facing skywards. M. x soulangeana is a hybrid between white-flowering M. denudata and M. liliiflora, a smaller tree with dark purple flowers. The saucer is one of the hardiest species, thriving as far north as USDA Plant Hardiness Zone 5b and doing equally well on the west and east coasts and in the Midwest. It will reach 30 to 40 feet tall at maturity with an equal spread. My favorite cultivars include ‘Alexandrina’, which has tepals that are white on the inside and purple on the exterior; ‘Brozzoni’, white with a rose-purple base; ‘Lilliputian’, a smaller form with diminutive flowers; and ‘Norbertii’, with soft pink flowers.
The Yulan magnolia (M. denudata, hardy to Zone 5b) is one of the earliest magnolias to bloom in spring. Because of their precocious nature, the fragrant, creamy white flowers are susceptible to frost damage. However, this medium-sized tree (to 30 feet) is a welcome addition to any garden.
Another fragrant early bloomer is the star magnolia (M. stellata, Zone 4). Star magnolias can be small trees or large shrubs, making them suitable for the smaller garden. Each flower is made up of 12 to 40 narrow white or pale pink tepals. ‘Centennial’, an introduction from the Arnold Arboretum, is more tall than broad and reaches 25 feet tall at maturity. This wonderful small tree deservedly received the Pennsylvania Horticultural Society Gold Medal, given to trees and shrubs that have outstanding ornamental attributes. ‘Rosea’ is soft pink in flower. ‘Royal Star’ opens pink and fades to white.
Magnolia x loebneri (Zone 4) is similar to the star magnolia—one of the parents of this hybrid—but generally flowers slightly later. ‘Leonard Messel’ bears fragrant, soft pink flowers that are larger than those of a star magnolia. At maturity, it will reach up to 15 feet tall and can be treated as a large shrub or small tree. ‘Merrill’ is also fragrant and has white flowers.
The Little Girl hybrids (Zone 5) are the result of breeding work by the U.S. National Arboretum in the late 1950s, using varieties of M. liliiflora and M. stellata as parents. In all, the arboretum released eight cultivars: ‘Ann’, ‘Betty’, ‘Jane’, ‘Judy’, ‘Pinkie’, ‘Randy’, ‘Ricki’, and ‘Susan’. These hybrids reach from 8 to 15 feet tall with an equal spread. The flower colors range from deep pink to a deep purple. They flower in midspring and therefore are less likely to be damaged by freezing weather.
Similar in color but larger in stature to the Little Girls are ‘Galaxy’ and ‘Spectrum’, both hardy to Zone 6. ‘Galaxy’ is a pyramidal tree that reaches 30 feet at maturity. The large flowers are deep pink-purple. ‘Spectrum’ has a broader habit and darker flowers than ‘Galaxy’. I have seen ‘Galaxy’ used effectively as a street tree.
The largest of the magnolias for North American gardens is the cucumber tree magnolia (M. acuminata, Zone 4). It is native from eastern Canada to Florida and can reach over 100 feet tall at maturity. It produces relatively small greenish yellow flowers that are often found high up in the tree and are hard to see from the ground.
Using M. acuminata as a parent, the Brooklyn Botanic Garden developed ‘Elizabeth’, the first yellow-flowering hybrid—considered the holy grail of magnolias when it was introduced in 1978. Subsequent hybridizing has resulted in more than 30 yellow magnolias on the market today. One of my favorites is ‘Butterflies’, which has up to 16 primrose yellow tepals and is hardy to Zone 5. All the yellow magnolias bloom late, so there is rarely an issue with the flowers being frosted.
‘Judy Zuk’ (Zone 5) is a more recently released yellow cultivar that resulted from a complex cross of M. stellata, M. liliiflora, and M. acuminata. The resulting hybrid bears stunning tulip-shaped flowers that are yellow suffused with pink. The fragrance is best described as tropical and fruity. The stature of the plant is very narrow and upright, making it perfect for tight spaces.
Of the North American native magnolias, the southern magnolia (M. grandiflora, Zone 6) is arguably the most popular. In the South, this evergreen tree can reach close to 100 feet. The leaves are large and shiny; several cultivars have an attractive brown “fuzz” or indumentum on the underside of the leaves. Southern magnolia is a wonderful specimen or screening tree. ‘Bracken’s Brown Beauty’ has a distinct pyramidal habit, shiny leaves, and rich brown indumentum. ‘Kay Parris’ is a diminutive selection for smaller gardens.
Most magnolias grow best in full sun and soil that is high in organic matter. Although most prefer well-drained soil, sweetbay magnolia (M. virginiana, Zone 5) is an exception that can tolerate poor drainage. It can grow at the edge of ponds or in marshy conditions. Native from Massachusetts to Florida, it is a beautiful addition to the landscape for those who prefer natives. Some cultivars are more evergreen than others, such as ‘Henry Hicks’ and ‘Green Shadow’. The relatively small ivory white flowers are intensely perfumed with a lemony-sweet scent, beginning in May and continuing sporadically throughout the summer. Sweetbay magnolia can be grown with a single trunk or as a multistemmed tree, ultimately reaching 35 to 40 feet.
The world of magnolias is vast. There is a magnolia to fit nearly every need and niche in the garden. New breeding work continues to expand size and color choices. I am a firm believer that every garden needs a magnolia!
Additional Magnolia Resources:
For more information on magnolias, visit magnoliasociety.org.