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38 the American Gardener

America’s MagnoliasAmerica’s MagnoliasBY GIL NELSON

Ranging from bashful woodland denizens to bold sun-loving giants, America’s native

magnolias offer plenty of interest for any garden.

BY GIL NELSON

Ranging from bashful woodland denizens to bold sun-loving giants, America’s native

magnolias offer plenty of interest for any garden.

MA G N O L I A S A R E the aristo-crats of America’s native trees,primordial relicts thousands of

millennia in the making and little more ad-vanced today than at the time of their ori-gin, when dinosaurs still rumbled theearth. Based on the fossil record, they datefrom at least the Cretaceous Period—135 to100 million years ago—and some expertsbelieve they may be even older than that.

The genus Magnolia is one of only twogenera in the magnolia family (Magnoli-aceae). Two species of tulip poplar (Lirio-dendron)—one in North America, theother in China—round out the family.There are about 220 species of magnoliasworldwide—not including the numerousselections, cultivars, and hybrids—nearlyall of which have been successfully intro-duced into horticulture. About two-thirdsare indigenous to Asia, ranging from Indiato China, Korea, and Japan. The remain-ing species are centered in the West Indies,Mexico, and the Americas.

Nine species are native to North Amer-ica, one of which is found only in thecloud forests of Mexico. The othereight—two evergreen and six decidu-ous—range from New York to Florida andwest to Texas, placing the eastern UnitedStates at the center of North American dis-tribution. But the native species, particu-larly the evergreen ones, have proven quiteadaptable outside their natural range andmany adorn gardens from the Midwest tothe West Coast and Pacific Northwest.

EVERGREEN NATIVESTwo evergreen magnolias occur in theeastern United States, both of which aresouthern in distribution and restricted innature mostly to the broad coastal plainsthat stretch away east and south from thePiedmont’s rolling hills.

Sweetbay (M. virginiana, USDA Har-diness Zones 6–9, AHS Heat Zones 9–6),sometimes called swamp magnolia, is thesmaller of the two. Its fragrant flowers aresmaller than other native magnolias—usu-ally measuring less than three inches widewhen fully open—but they bloom inshowy abundance in late spring and earlysummer. The two-toned leaves are pale

green above and silvery white beneath,causing well-exposed trees to shimmer be-tween these colors in the slightest breeze.

Sweetbay is quite variable in nature, andtwo primary varieties have been identified.The northern one (variety virginiana) istypically a large multi-stemmed shrub thatusually doesn’t exceed 20 feet in height. Itis slightly hardier than its southern cousin,to USDA Zone 4 or 5, but may lose itsleaves in winter in cooler zones. The south-ern form (variety australis) can reachheights of 50 feet or more in the garden(nearly 100 feet in the wild) with an opencrown and attractive smooth grayish

trunk. It performs best in USDA Zones 7to 10. Although both varieties are wetlandplants in nature, they do not require wetsoils in the garden and surprisingly willthrive in dry, sunny locations.

A few cultivars of sweetbay are avail-able. Andrew Bunting, curator of theScott Arboretum of Swarthmore College,says, “One of our favorites is M. virgini-ana var. australis ‘Henry Hicks’, which isa selection made here at the Scott Arbore-tum. In our climate it is semi-evergreen.We also grow ‘Santa Rosa’ which has largeglossy, dark green leaves.”

Nancy Buley, director of marketingand communications for J. Frank

Schmidt and Son tree nursery in Boring,Oregon, likes ‘Jim Wilson’, which is soldunder the trademark name Moonglow.Named after a well-known garden writer,it has an upright habit, tends to be ever-green, and is hardy to USDA Zone 4 or 5,according to Buley.

The other native evergreen species issouthern magnolia (M. grandiflora, Zones7–9, 9–6), which is much larger than thesweetbay, with thick, leathery, dark greenfoliage. Its attractive form and popularitywith gardeners and landscape designershave resulted in the selection of more than125 cultivars.

Standard southern magnolias tend toget so large at maturity that they can growout of scale with residential landscapes.This has driven breeders to seek out small-er selections with compact, columnarforms. Three of the more popular are ‘Lit-tle Gem’, ‘D. D. Blanchard’, and ‘Brack-en’s Brown Beauty’. All have shorter leavesthan the species—often less than six inch-es long—with a covering of attractive rustyor dark brown hairs on the undersides.

‘D. D. Blanchard’ is one of the mostpopular tree-sized selections, reaching 50feet tall and 35 feet wide.

‘Little Gem’ is perhaps the best com-pact form, often growing as a large, dense-L

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Opposite: Rare in the wild, bigleaf magnoliais a striking tree with leaves up to three feetlong and eight-inch-wide fragrant flowers.

Sweetbay magnolia, left, isprized for its silvery-greenleaves—evergreen in warmerregions—which seem toshimmer in a breeze. It alsobears deliciously fragrant earlysummer flowers, such as thisone, above, from the cultivar‘Henry Hicks’.

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40 the American Gardener

ly foliaged shrub, but sometimes forminga small tree. It is typically less than 30 feettall, about half as wide, and is useful as aspecimen or screening plant. ‘Little Gem’is excellent for gardens in warmer climatesand may suffer during severe winters far-ther north.

‘Bracken’s Brown Beauty’(Zones 6–9,10–4), which usually tops out at 30 to 50feet tall and 30 feet wide, is hardier than‘Little Gem’ and has become popular ingardens as far north as New England. Itmay suffer leaf burn or even defoliate com-pletely in severe winters, but is among theselections of choice for colder climates.

‘Kay Parris’ and ‘Edith Bogue’ (6–9,9–6) are similar in size to ‘Bracken’s BrownBeauty’ and should also be tried in north-

ern gardens. ‘Kay Parris’ features a pro-longed flowering period, striking blos-soms, and glossy green leaves that arenearly orange beneath. It may prove to behardier than its USDA Zone 7 rating sug-gests, and its form may be even better thanthat of ‘Little Gem’. A relatively new in-troduction named Alta® (‘TMGH’) is re-ported to grow to 40 or 50 feet with acolumnar habit.

Regardless of attempts to breed coldhardiness into this species, Magnolia gran-diflora is essentially a southern plant.

DECIDUOUS NATIVESWhile the evergreen species are by far themost popular of the native magnolias, thedeciduous species should not be over-

looked—especially the big leaf forms. TheAshe, bigleaf, and umbrella magnolias arespectacular in the garden, featuring hugeflowers and graceful forms. The flowers ofAshe and big leaf magnolias can be nearlytwo feet wide when fully open, withcreamy white tepals that sport a large pur-ple blotch at the base. The flowers of um-brella magnolia are all white and about halfthe size of its large-leaved relatives. Theleaves of all three are exceptionally large,potentially to more than three feet long inthe bigleaf and Ashe magnolias, and up totwo feet in umbrella magnolia. The onlyother widely used deciduous natives in-clude the smaller-leaved cucumber mag-nolia (M. acuminata) and its diminutivevariety, yellow cucumber magnolia (M.

Southern magnolias, like the one growing at the American Horticultural Society’sheadquarters in Virginia, above, make a grand statement in the landscape.Many selections are available, including ‘Kay Parris’, top right, which bearsstriking creamy white flowers from late spring to midsummer, and ‘D.D.Blanchard’, right, which features attractive foliage and a pyramidal shape.

acuminata var. subcordata).Ashe magnolia (M. ashei, Zones 6–9,

9–6) is, at once, the rarest of the deciduousnatives in the wild and one of the mostpopular with gardeners. Named for W. W.Ashe, an early 20th century botanist whofirst collected the plant in the Florida pan-handle, its natural habitat is restricted tobluffs, ravine slopes, and a few upland

woods between Tallahassee and Pensacola.Yet, it has proven cold hardy in trials toUSDA Zone 4 and is comfortably ratedhardy to at least USDA Zone 6. In fact, thelargest Ashe magnolia on record grows atthe Henry Botanic Garden in Gladwyne,Pennsylvania, about 1,000 miles north ofits current natural range.

Its popularity with gardeners is due toits manageable size in residential land-scapes, coupled with its tendency for flow-ering at a young age. Garden plantsaverage well under 30 feet in height andwidth at maturity, and may express them-selves as gangly, single-trunked shrubs orsmall trees. The long, thick, often con-torted branches are highly attractive inboth winter and summer, and the largeleaves add tropical flair to temperate gar-dens. Ashe magnolias produce their firstflowers in as little as two years from seed.Ashe magnolia occurs in nature in the un-derstory of shady woodlands, but it per-forms very well in sunny openings and ismost enjoyed as a specimen tree to show-case its large leaves and oversized flowers.

Ashe magnolia is closely related to

bigleaf magnolia (M. macrophylla, Zones6–9, 9–6); indeed, some experts consid-er it a variety of its slightly larger-leavedcousin. The two are well separated innatural range, but are very attractivewhen planted near one another in thegarden. Bigleaf becomes much larger—to at least 50 feet tall—and is more tree-like at maturity. However, it takes muchlonger to reach flowering age. Reports of10 to 15 years from seed to first flower arecommon. When grown in sun, it takeson a full form with a wide, attractivecrown. Phil Normandy, plant curator atBrookside Gardens in Wheaton, Mary-land, is particularly fond of a grouping ofthree bigleaf magnolias at a satellite gar-den of Brookside. “Originally these trees

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Precocious ashe magnolias start bloomingwhen they are only two or three years of age.

The bold, dramatic foliage on this bigleaf magnolia, growing at Daniel Stowe BotanicalGarden in North Carolina, makes it a standout in the landscape.

SourcesBroken Arrow Nursery, Hamden, CT.(203) 288-1026. www.brokenarrownursery.com.

Greer Gardens, Eugene, OR. (541)686-8266. www.greergardens.com.

Mail Order Natives, Lee, FL. (850)973-4688. www.mailordernatives.com.

Nearly Native Nursery, Fayetteville,GA. (770) 460-6284. www.nearlynativenursery.com.

Rare Find Nursery, Jackson, NJ.(732) 833-0613. www.rarefindnursery.com.

Woodlanders, Inc., Aiken, SC. (803)648-7522. www.woodlanders.net.

ResourcesMagnolias: A Gardener’s Guide byJim Gardiner, Timber Press, Port-land, Oregon, 2000.

The Magnolia Society International,www.magnoliasociety.org.

The World of Magnolias by DorothyJ. Callaway, Timber Press, Portland,Oregon, 1994.

were planted in partial shade, but nowthey are growing in more or less full sun,”says Normandy. At more than 30 feet tall,they offer a very dramatic look.”

Umbrella magnolia (M. tripetala,Zones 4–9, 9–5) also has large leaves—upto at least 20 inches long and 10 incheswide that taper to a point at the base, un-like the slightly lobed leaf base of bigleafand Ashe magnolia. The flowers have sixto 12 tepals and are about eight incheswide. Most umbrella trees top out at lessthan 50 feet tall and may form erect, sin-gle-trunked trees or very large multi-stemmed shrubs. The common namestems from the spreading leaves, whichtend to radiate laterally from the branchtips, creating an umbrellalike canopy. Um-brella magnolia grows naturally fromsoutheastern New York southward to theFlorida panhandle (where only a few pop-ulations are known), and west to Arkansas.It is adaptable and easy to grow in the gar-den and flowers best in light shade to fullsun in rich, moist soils. It is most at homein a naturalistic woodland garden, but sin-gle-trunked forms serve well as specimentrees in more open landscapes.

Mountain magnolia (M. fraseri, Zones4–9, 9–6), an endemic species of mountain

coves and rich woods of the southern Ap-palachians, has moderately large leaves andelegant, fragrant white flowers. Its nativerange is from West Virginia into easternKentucky and Tennessee, and southwardto northern Georgia. Reported to be moredemanding to grow than other native de-

ciduous magnolias, it grows best in moist,acid soils and thrives alongside streams.The pyramid magnolia (M. pyramidata,Zones 7–9, 9–7), considered by some to bea variety of mountain magnolia, is a coastalplains counterpart ranging mostly east andsouth of the Piedmont.

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FLOWERS, FRUIT, AND POLLINATORSThe magnolias’ ancient affinities are most evident in the struc-ture of their flowers and fruit. Unlike many perfect flowers, whichfeature clear division of sepals, stamens, and pistils, magnoliaflowers consist of various parts that are often difficult to tellapart. Numerous stamens and pistils spiral around an erect cen-tral axis subtended by a whorl of creamywhite petallike structures. In most speciesthe petals and sepals are so similar thatexperts refer to them as “tepals,” a botan-ical catchall term that serves where pre-cise morphological language fails.

Magnolia flowers are protogynous,which means that the pistil of an individ-ual flower becomes receptive (matures)before that flower’s stamens release theirpollen. Their primary pollinators are bee-tles, which apparently co-evolved with thegenus in an intriguing pollination mecha-nism. In bud, magnolia flowers are cov-ered by a fuzzy bract that encircles and protects the developingbloom. The stigmas become receptive just before the floweropens, requiring the beetles to squeeze or chew their way through

the thick fleshy tissue to get to the stigmas and stamens. Insmaller-flowered species, the flowers open only partly during thefirst day, close during the evening, and reopen the second dayto shed pollen and drop their stamens. The larger-flowered formsoften remain at least partially open throughout pollination.

Magnolia fruits are often describedas cones, which is not technically ac-curate. True cones, with unprotectedovaries and overlapping scales, are thepurview of the conifers. The magnoliafruit, on the other hand, is a follicle—acapsulelike pod that derives from a sin-gle ovary and splits at maturity along asingle seam. Since each magnoliaflower has many ovaries, it producesmultiple follicles that are clustered toform attractive conelike structures. Atmaturity the follicles open to exposeshowy red seeds that dangle on thin col-

orful threads reminiscent in function and structure to an um-bilical cord. The colorful seed coat—technically an aril—en-cases and protects the developing embryo. —G.N.

The cone-shaped fruits of umbrella magnolia turn pinkish red in autumn.

Southern magnolia’s decorative red seeds

Yellow flowers on trees are one of the“holy grails” of horticulture, so it’s not sur-prising that the cucumber magnolia (M.acuminata, Zones 4–9, 9–2), with itsgreenish yellow flowers, has been of par-ticular interest to plant breeders. Namedfor the shape of its young fruiting “cones,”cucumber magnolia is the hardiest andmost widespread of the American magno-lias, ranging from a small population in theFlorida panhandle north to the Canadianside of Lake Erie. It can grow to more than100 feet high, making it one of the tallestdeciduous native magnolias. Its leaves growto eight inches long, tapering to a point.

The best yellows are produced by thesmaller, less widespread, and less hardyyellow cucumber magnolia (M. acumi-nata subsp. subcordata, Zones 7–9, 9–7).

It fits well into residential landscapes as asmall tree or large shrub that usually doesnot exceed about 30 feet tall. The bestspecimens have distinctly yellow tepalswith flowers that appear in spring beforethe new leaves expand.

Cucumber magnolia has given rise tonumerous cultivars, including the popu-lar M. ✕ ‘Butterflies’, a cross between M.acuminata and the Chinese M. denudata‘Sawada’s Cream’. ‘Butterflies’ is the bestand most widely grown of the yellow-flowered magnolias and extends the har-diness range for yellow-flowered formsnorthward to USDA Zone 4.

CARING FOR NATIVE MAGNOLIASMost magnolias thrive in slightly acidic,well-drained soil with a pH of 5.5 to 6.5.Evergreen species usually grow best infull sun, while the deciduous species arebetter suited to part shade, especially inwarmer regions.

Early fall is the best time to plant mag-nolias. Dig a hole about twice the width ofthe rootball but not much deeper. Gentlyagitate and spread the roots along the edgesof the container ball; magnolias have ten-der roots but it helps to spread them a lit-tle before planting. Leave the top of theroot ball about an inch above ground leveland fill the remaining void with the rest ofthe excavated soil.

Magnolias have shallow root systems,so add a layer of mulch around the base of

the tree. They also have thin bark, so avoidmechanical weed trimming or other ac-tivities that might injure the bark, provid-ing an entry point for pathogens.

Water newly planted trees regularlyuntil they are well established, but asidefrom that, little supplemental irrigationshould be needed except during droughts.Avoid overwatering because most magno-lias are prone to root rot.

Magnolias generally need little pruningother than to remove crossed branches orfor other cosmetic purposes. (For infor-mation on propagating native magnolias,click on a web special linked to this articleon the AHS website at www.ahs.org).

LONG-LASTING BEAUTYRegardless of which species you choose,native magnolias add a distinctive charmto gardens through all four seasons and, inmost cases, over a long lifespan. The leavesrange from lush and tropical-looking onthe deciduous species to glossy and two-toned on the evergreen magnolias. Theirattractive forms and showy, fragrant flow-ers are, in my opinion, unsurpassed amongAmerica’s native trees. And in late summerand fall the sculptural fruits and bright redseeds add their own decorative touch. �

Gil Nelson is an author, photographer, andbotanist based in Georgia. His next book, aguide to native plants for southern gardens, isscheduled for release in 2010.T

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Yellow cucumber magnolia has been usedby breeders to develop popular yellow-flowered magnolia hybrids such as ‘GoldStar’, left, and ‘Butterflies’, above.

Mountain magnolia, native to the southernAppalachians, blooms in spring.