Horticultural Highlight: Magnoliaceae

April 1, 2012

Magnolia x soulangiana, saucer magnolia

My magnolia tree is going mad!

what delicious blossoming:

on branches bare a month ago

this blush, first flush of Spring,

on limbs unburdened by their weight

not buds, but birds, burgeoning:

rose-pink breasted, moon-white crested

fledglings and doting pairs,

there’s no mistaking them

                                –Bet Briggs

The notable plant collector, Ernest Henry Wilson (1876-1930) wrote of magnolias: “Aristocrats of ancient lineage, possessed of many superlative qualities are the magnolias. They have the largest flowers and largest individual leaves of any hardy group of trees. No other genus of hardy or half-hardy trees and shrubs can boast so many excellences…Their free-flowering character and great beauty of blossoms and foliage are equaled by the ease with which they may be cultivated.”

Throughout Mount Auburn’s landscape, during April, we all are witness to the bold, yet graceful, elegant, yet exuberant, floral displays that both Briggs and Wilson were moved to praise with superlatives. As members of the botanical family Magnoliaceae, these are descendants of some of the earliest flowering plants. Fossil remains show members of this family grew in the Cretaceous Period (145-65 million years ago). Before that time, the earth’s surface was primarily dominated with conifers, cycads, ferns, and equisetums (horsetails). Today, the genus Magnolia, includes 85 to 120, deciduous and evergreen species (depending on taxonomic interpretation), primarily native to east and southeast Asia, and eastern North America.  This genus, named by Carl Linnaeus (1707-1778), father of modern taxonomy, honors the French botanist, Pierre Magnol (1638-1715), Director of the Royal Botanic Garden of Montpellier, and professor of botany. Magnol in 1689, published and postulated the concept of plant families, based on morphological characteristics. This was still a time when common belief held that all species came into existence by divine creation.

Our modern, springtime infatuation with magnolias, is due to the large flowers, which can warm anyone’s mood, in spite of our often fickle, early-spring, New England weather. These flowers are actually composed of tepals, a term introduced specifically for magnolias, in 1950, for a floral part that is not clearly differentiated as being either a sepal or a petal.  Many of these tepals may last for several weeks in flower, unless a periodic late frost follows their abundant display. Having evolved before bees, butterflies, or moths existed, these flowers were, and still are, pollinated by beetles, or beetle-type insects.

At Mount Auburn, there are over seventy magnolias, representing 9 species, three hybrids, and 27 cultivated varieties. We will focus here on a few precocious forms, which flower before their leaves emerge.

Magnolia denudata

Magnolia denudata ,Yulan magnolia, is named for its region of origin in China. Its specific epithet, denudata, was given by Linnaeus, and alludes to its being denuded of leaves when flowering, perhaps unusual for such a large flower at that time. This may be one of the first flowering tree used ornamentally, as Buddhist monks have grown it to adorn their temples for the past 1300 years. It was introduced into western horticulture in 1780 by Sir Joseph Banks (1743-1820), an amateur scientist of wealth, who had also served as botanist, on Captain James Cook’s (1728-1779) first round-the-world voyage in 1768-1770. The flowers are a creamy, white color, with 6-9 tepals, that hold their upright, cupped-shape longer than other magnolias. The flowers have a sweet, lemony scent. You may find specimens of Yulan magnolia in the Asa Gray garden, and on Narcissus Path (near Linden Path).

Magnolia stellata, star magnoliaMagnolia stellata, star magnolia, is one of the most beautiful, and popular magnolias. It was first introduced from Japan in 1861 by Dr. George Rogers Hall (1820-1899), a Harvard trained physician, turned trader, who sent living plants from Japan directly to New England. The exquisite charm of these lightly fragrant, flowers lies chiefly in the large number of splayed-open, narrow, strap-shaped, tepals, which may vary from12 to 18, to 40. The color is generally white, although there are cultivated forms with pink tepals. You may see star magnolias on Bigelow Avenue, Beryl Path, and Bellwort Path, as well as other locations.

Magnolia x soulangiana, saucer magnoliaMagnolia x soulangiana, saucer magnolia, is probably the best known and most widely planted of all the magnolias. In Boston, these are the magnolias that line Back Bay’s Commonwealth Avenue.   This is a hybrid, which is a plant with parentage from two different species, in this case the lineage is Magnolia denudata and Magnolia liliiflora. In 1820, this hybrid was created by, and named for, Etienne Soulange-Bodin (1774-1846), a French, retired cavalry officer, turned agronomist. The cup-and-saucer shaped flowers have a pink color outside, but white inside, and generally have 9 tepals.  At Mount Auburn, we have fine examples growing on Indian Ridge Path, Bigelow Avenue, Magnolia Avenue, Asclepias Path, and Willow Pond Path.

Magnolia x loebneri ‘Merrill’, is a hybrid between Magnolia stellata and Magnolia kobus and has fragrant, white flowers, with 10-17 tepals. When mature the ‘Merrill’ is 25-30 feet in height. There is a grand specimen on Spruce Avenue, at Thistle Path, our area known as Alice’s Fountain, as well as several other locations throughout  our landscape.

Magnolia 'Elizabeth"Magnolia ‘Elizabeth’, was the first light-yellow-flowered, hybrid available. Introduced by the Brooklyn Botanic Garden, the lineage is Magnolia denudata (with white flowers) and Magnolia acuminata (with  green-colored  flowers).  This will become a medium-sized tree.  We have two specimens, at the corner of our administration building, and at the corner of Magnolia Avenue and Oak Avenue.

We also grow six of the eight “Little Girls” magnolias. These low-branched, and shrubby trees may only reach-15-feet high, spreading to an oval form. All were introduced from the U. S. National Arboretum, and six (‘Ann’, Betty’, ‘Judy’, ‘Randy’, Ricki’, and ‘Susan’) are the result of hybrid crosses between Magnolia stellata ‘Rosea’ and Magnolia liliiflora. “Ann’ has erect, fragrant, flowers, with a deep, purple-red color, and is planted in a small triangular bed on Cherry Avenue. ‘Susan’, has narrow, goblet-shaped, fragrant, flowers of the reddest color, and is found nearby in another triangular bed on Cherry Avenue.  ‘Betty’ has large, eight-inch, violet-colored, flowers, with 12-19 tepals, and is on Cedar Avenue.  ‘Randy’ has 9-11 red-purple tepals, which fade to a rich pink color, and is planted between Cedar Avenue and Cypress Avenue. We do not grow ‘Judy’ or ‘Ricki’.

 ‘Jane’ was a cross between Magnolia liliiflora ’Reflorescens’ and Magnolia stellata ‘Waterlily’ and has fragrant, red-purple, flowers and is found in the same triangular bed, already mentioned, as ‘Susan’, on Cherry Avenue.  Lastly, ‘Pinkie’, the latest of these hybrids to flower, has the palest flowers, and can be found on Juniper Path.  These “Little Girls” magnolias were named to honor U. S. National Arboretum secretaries, or staff wives and daughters.

This year, these precocious flowers which annually flower before the leaves emerge, opened three to four weeks ahead of their average blooming time. The bad news is that we had two nights with below freezing temperatures the last week of March, resulting in browning, frost-damage. This is unfortunately a periodic occurrence, with our truly variable New England weather.  On your next visit to Mount Auburn, look for some of the magnolia flowers that opened after our end-of-March frost.

~

About the Author: Jim Gorman

Visitor Services Assistant View all posts by Jim Gorman →

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