PLANT OF THE WEEK: Southern Magnolia

By on August 25, 2011.

Magnolia grandiflora–  Southern Magnolias are well known in the southeast U.S. and have spread across the country and Europe due to their evergreen foliage , large robust flowers and overwhelming fragrance.  The Magnolia family is heavily hybridized and M. grandiflora is no exception.  Numerous cultivars exhibit grossly different attributes and the wrong selection can spell disaster for a design at maturity. While highlighting the general qualities of this tree, this update also provides a break down of several magnolia cultivars and can help you select the one that best suits your needs.

Size/Habit/Lifetime: Size and habit ranges greatly among cultivars and is addressed below. The native specie is pyramidal to open with age with a stong central leader rising to over 80′ tall and width’s reaching 30 -50′. National champion from Mississippi measures 98′ x 90′ !  Coarse  in texture.

Culture: Full sun to partial shade depending on soil and moisture type. In moist, peaty soils it thrives in full sun. Drier and less fertile soils suggest some partial shade without regular irrigation. Once established, Southern Magnolias are moderately drought tolerant. They are noted for having expansive root zones and often spread well beyond the canopy drip line. Overall, M. grandiflora adapts well to slightly alkaline/acidic, clay and sandy soils. Transplants well ball-n-burlap or from container.

Leaf/Stem: Leaves are simple, alternate, elliptic to ovate in shape and varying in color and luster. Generally dark lustrous green above and lighter underneath with rusty pubescence. Length is 8 to 12″, width is half of that. Lower branches can droop to the ground and may be trimmed to provide pedestrian or vehicular access below. Leaves decompose quite slowly and although they are evergreen, they drop large quantities and can be messy if not managed.

Flower/Fruit:  Aristocratic flowers are the defining feature of Southern Magnolias.  They are large, creamy white and the fragrance is unmatched the world over. Measuring 6 to 12″ in diameter with 6, 9 or 12 petals. Blooms May to June, earlier in the deep south, some cultivars later than others. Fruit is a cone like follicle of red shiny seeds. Quite showy and maturing Sept-Nov.

Use:  As a street tree if given proper room, can be a large border screen,  a single specimens in a lawn, used in natural groupings, for long regal entry drives, and espaliers. Very usable in many situations with proper cultivar selections.

Cultivars:

  • Alta: An upright and conical habit. Dark green, glossy foliage with brown back. Prefers heavy soils over sand. Late spring to summer blooms. Size 15-20′ H x 8-10′ W.  Great for screening, easy transplanter.
  • Bracken’s Brown Beauty:    Noted as one of the better cultivars, it offers full, dense foliage and uniform shape with darker leaf underside.  Leafs smaller, about 6″ with undulating surface. Flowers also smaller to 6″. One of the most cold hardy specimens,grown well into the Ohio valley.  Size 30-50′ H x 15-20″ W
  • Cinnamon Twist: A larger variety with a slight, axial twist.
  • Claudia Wannamaker: Broad and dense with dark green foliage. More open than ‘ Bracken’s ‘. One of the finer large size varieties; sizes to 60′ H x 30’ W.  Flowers at an early age.
  • D.D. Blanchard: Very dark and shiny leaves with near orange-brown backing. Compact and pyramidal shape. More open than ‘Claudia Wannamaker’Large tree size 60′ H x 40-50’ W
  • Edith Bouge: A large variety with lustrous more narrow leaves. More cold hardy and better suited to the north as it in more loose and open than ‘Bracken’s’.
  • Hasse:  A medium sized more narrow variety reaching 25-35′ H x 8-15′ W. Conical and tapering in shape. Reddish brown underside with regular bloom season, sporadic into the summer. Better suited for restricted spaces.
  • Little Gem: Compact and upright to oval shape. Good selection for extreme southern zones. Matures 30′ H x 8-12′ W. Generally seen as smallest of all cultivars.
  • Majestic Beauty: Very large, profuse flowering. Size 50′ H x 25-30′ W. More open in habit than others. Best suited for large properties.
  • Victoria: From Victoria, British Columbia, one of the hardiest selections. Better cultivars can be selected for the south.

Citations:

Dirr, Michael A., Manual of Woody Landscape Plants, Stipes Publishing, 1998

Panhandle Growers, Milton, Fl

University of Florida IFAS: Northern Trees

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