R. Wayne Mezitt is a 3rd generation nurseryman and a Massachusetts Certified Horticulturist, now chairman of Weston Nurseries of Hopkinton and Chelmsford, MA. He has served as president of the Massachusetts Nursery and Landscape Association, the New England Nursery Association, and the American Nursery and Landscape Association, based in Washington, DC.
Mention magnolias, and most New Englanders envision those tulip-shaped pink or star-like white flowers that appear as the days grow warmer, always a much appreciated welcome-to-spring event. But some years these early season flowers can be affected by freezing temperatures that spoil that experience. Later-flowering magnolias avoid this challenge while adding a new dimension to your enjoyment of your summer garden.
By the end of May and into June, the Oyama Magnolia (M. sieboldii) opens its fragrant nodding white blossoms over a period of three weeks or longer. Multi-stemmed and shade tolerant, it's surprisingly winter hardy, thriving even into central New England. It grows to nearly 20 ft. in this region and should be planted so you can look upward into the branches to enjoy the striking red center of each flower.
The flowers of Sweetbay Magnolia (M. virginiana) have upward-facing, lemony-scented, creamy-white flowers with prominent yellow centers over a several week period in June. It tolerates moist conditions, eventually reaching as much as 25 ft. high. Shiny green leaves flutter their silvery undersides in the summer breeze, and its flowers continue sporadically into July and even August. Near Gloucester, the town of Magnolia, Massachusetts is named for a native grove of these trees.
The latest-blooming of the hardy magnolias for this region (at 30 ft. perhaps too imposing for many home landscapes) is the Bigleaf Magnolia (M. macrophylla). By early June this impressive tree has already produced its unique display of tropical-looking two-foot-long leaves with silvery undersides that distinguish it from any other plant hardy in this climate. On mature trees foot-wide fragrant white blooms, opening day by day all month, make a spectacular primordial statement that delights every garden viewer.
A smaller-scale version is the Ashe Magnolia (M. macrophylla ashei), with similarly-sized foliage, growing to about 20 ft. This is a precocious multi-stem tree, offering similarly huge flowers a week or two earlier than the species, and flowering at a very young age. An added bonus with both Big-leaf and Ashe Magnolia is their October display of fist-size, rounded, cone-like fruits that open to reveal rose-salmon-colored seeds. And the soft "thud" of their falling foliage is an unmatched auditory experience.
If you are truly adventurous, you might want to push the climate limits and try one of the Southern Magnolias (M. grandiflora). Even though they have not been considered reliably winter-hardy in this region, recent winters have proven sufficiently gentle to enable some of these to survive and produce their fragrant tulip-shaped creamy-white summer flowers. Choose a cultivar like 'Bracken's Brown Beauty' and 'Edith Bogue', both of which have performed reasonably well in some locations in our Hopkinton gardens over the past decade. Make sure these are planted where the soil stays moist, ideally in an eastern or northern exposure, protected from the wind, where they avoid winter sun which can damage foliage and buds.
Most of these summer-flowering magnolias are not yet commonly used in New England gardens. All (except Southern Magnolia) are deciduous, easy to grow and add a new dimension to your late spring and summer garden enjoyment. You can see great examples at Tower Hill Botanic Garden in Boylston, the Mount Auburn Cemetery and Arnold Arboretum in Boston. Also learn more about them from experts at your local garden center and on the internet.