Saving Spring: Growing Rare and Endangered Magnolias

A magnolia tree blooms in the Japanese Garden. Photo by Kent Burgess.

An emblem of spring, magnolias are celebrated for their beautiful white and pink flowers that bloom early in the season. While common in home landscapes, half of all magnolia species are threatened with extinction in the wild. They are found around the globe, and are mainly threatened by logging activity as well as habitat loss due to land conversion to agriculture. 

The Missouri Botanical Garden will be planting 12 different magnolia species in the new landscape around the Jack C. Taylor Visitor Center, including rare and endangered species. Learn more about each species, and how the Garden is working to save them, below.

Magnolia acuminata 

Photo by Jessie Harris, courtesy of TROPICOS.

This large magnolia tree commonly known as cucumber magnolia is native to eastern North America, reaching its largest size in the southern Appalachian region. It is the only magnolia native to Missouri. Unlike most magnolias, the flowers are not showy. It is named for the green, warty, cucumber-like fruits that follow the flowers.

Magnolia ashei

Photo by Jessie Harris, courtesy of TROPICOS.

A small deciduous magnolia with very large leaves and attractive white flowers, Magnolia ashei is considered the rarest species of magnolia in North America, and is restricted to scattered sites in the Florida panhandle. This tree is already planted in the south landscape.

Magnolia dawsoniana ‘Clarke’

Magnolia dawsoniana “Clarke.” Photo by Philip Bouchard, Creative Commons.

The Dawson magnolia is a small tree native to Sichuan and Yunnan in China. It is endangered in the wild due largely to logging and resulting deforestation. This cultivar produces large, fragrant, white-streaked-rose pink flowers in early spring. 

Magnolia grandiflora ‘Edith Bogue’

Magnolia grandiflora ‘Edith Bogue.’ Photo courtesy of Missouri Botanical Garden’s PlantFinder.

This broadleaf evergreen tree is noted for its attractive dark green leaves and large and extremely fragrant, lemon-scented flowers, that bloom in late spring to early summer. It is native to moist wooded areas in the southeastern United States from North Carolina to Florida and Texas. ‘Edith Bogue’ is a cultivar that is noted for its excellent winter hardiness. Over time, this cultivar will grow to 60 feet tall by 30 feet wide.

Magnolia kobus

Kobus magnolia in the English Woodland Garden. Photo by Tom Incrocci.

This species is a small tree native to Japan noted for its late winter to early spring bloom of goblet or cup-shaped, fragrant flowers. These white blooms, often pink-tinged, are about four inches across and open in March before the foliage emerges.

Magnolia macrophylla

Leaves of Magnolia macrophylla. Photo by Tom Incrocci.

Native to the southeastern United Sates and eastern Mexico, the big-leaf magnolia is noted for its huge oblong-obovate leaves. Growing up to 30 inches long, they are the largest simple leaves of any tree indigenous to North America. Fragrant, open, cup-shaped flowers to 8-10 inches wide bloom in May. Flowers are white with rose-purple at the petal bases. Although quite large, the flowers are often located far off the ground and are not always easy to see close up.

Magnolia obovata 

Magnolia obovata leaves glimmer in the morning sunlight in the English Woodland Garden. Photo by Tom Incrocci.

Otherwise known as the Japanese bigleaf magnolia, this is a large-leaved deciduous tree that matures to 25 to 40 feet tall. The fragrant flowers bloom in May-June. It is native to mixed broadleaf forests from sea level to 6,000 feet in Japan and the nearby Kuril Islands of Russia. The leaf is sometimes used in Japan to wrap food.

Magnolia sieboldii 

A bloom of Magnolia sieboldii. Photo courtesy of Missouri Botanical Garden’s PlantFinder.

This deciduous shrub or small tree native to Japan, southeastern China and Korea produces fragrant white flowers with crimson stamens. It blooms for about 6 weeks, from late May to July.

Magnolia stellata 

Star magnolia, Magnolia stellata ‘Royal Star. Photo by Tom Incrocci.

Magnolia stellata is an endangered small tree from Japan. Its wild populations have declined as a result of massive urban development.

Magnolia stellata ‘Chrysanthemumiflora’ combines deep pink coloration in bud that changes to light pink when fully open. The flowers have a large number of petals (often more than 40) and resemble a chrysanthemum. Magnolia stellata ‘Royal Star’ is a popular cultivar that has slightly larger and showier flowers than the species.

Magnolia virginiana var. australis ‘Perry Paige’

Magnolia virginiana var. australis. Photo courtesy of Missouri Botanical Garden’s PlantFinder.

Commonly called sweet bay magnolia, Magnolia virginiana is native to the southeastern United States. Foliage is evergreen to semi-evergreen in warmer climates and semi-evergreen to fully deciduous in colder climates. The flowers are creamy-white and about 4″ wide. This cultivar is unique for its short, bushy form.

Magnolia × loebneri ‘White Rose’ – This is a hybrid magnolia (M. kobus x M. stellata) that grows 20 to 30 feettall with a rounded crown. It is more often grown in a multi-trunked form that as a single trunk tree. Fragrant star-like white flowers, 4-6 inches wide, with 10-15 petals appear in early spring before the foliage in March– April.This cultivar is known for its rose-like, white double flowers.

Magnolia tripetala

Magnolia tripetala. Photo by Daria McKelvey.

Commonly known as umbrella magnolia, this species of magnolia has leaves that appear in whorl-like clusters at the stem tips resembling the spokes of an umbrella. Magnolia tripetala is a widespread species, occurring from Florida to Massachusetts and west to Oklahoma. Although secure through much of its range, it is restricted to relatively small, relictual, mesic habitats in its southwestern range. The smaller, disjunct populations that occur in Oklahoma, Arkansas, Mississippi, and Florida do face a number of threats. The biggest threat these populations face may be global climate change and its impacts, but they are also at risk due to the nature of the small scattered populations, limited gene flow, development, and land clearing. 

Garden staff are actively working to save Magnolia tripetala in the wild. Photo by Jared Chauncey.

Active Conservation

The Missouri Botanical Garden is actively working on an ex situ conservation project involving Magnolia tripetala, funded by the American Public Garden Association and United States Forest Service Tree Gene Conservation Partnership, establishing a living gene bank for under-represented populations of this species. The objectives of the project are:

1. Scout and document Magnolia tripetala populations in Oklahoma, Arkansas, Mississippi, and Florida,

2. Collect seed and/or cuttings, prioritizing localities for which there are few or no ex situ collections recorded. Collect herbarium vouchers and DNA samples for every population or locality.

3. Distribute propagules to other institutions for the creation of living gene banks of highly-documented, wild source accessions of the target species.

By the end of the project, Garden staff had:

  • Mapped 160 Magnolia tripetala occurrences
  • Created Herbarium vouchers from 24 sites
  • Shared Herbarium vouchers with the National Arboretum in DC.
  • Taken DNA samplesfrom 58 trees and deposited in the Garden’s DNA bank. 
  • Made a total of 52 seed collections, which are currently being grown at the Oertli Hardy Nursery. One is being trialed in tissue culture. Plants will be distributed later in 2023.

Most magnolias seed is not “orthodox”, meaning it is unsuitable for traditional seed bank storage. This means that the Garden must grow all the seed staff collected. Since the Garden can’t grow all of the resulting trees on grounds, staff will distribute plants to other botanical gardens later in the year for the creation of living gene banks, otherwise known as a metacollection.

Rebecca Sucher
Senior Manager, Living Collections

Catherine Martin
Senior Public Information Officer

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