Sweetgum or American Sweetgum

(Hamamelidaceae - Witchhazel Family)

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• Form
  • large shade tree
  • maturing at 60' tall by 40' wide under urban conditions, but much larger in the wild
  • upright pyramidal growth habit in youth, becoming spreading, irregular, and open with age
  • rapid growth rate

• Culture
  • full sun to partial sun
  • performs best in full sun in moist, deep, rich, slightly acidic soils, but is adaptable to dry soils, wet or permanently moist soils, shallow soils, poor soils, clay soils, and neutral to slightly alkaline pH soils
  • propagated by seeds, rooted stem cuttings, or budded/grafted onto seedling understock
  • Witchhazel Family, with a few relatively minor disease and pest problems, but chlorotic foliage can result from alkaline pH soils that lead to iron and nitrogen deficiency
  • commonly available, primarily in ball and burlap form
  • Sweetgum is somewhat sensitive to being transplanted in the Autumn (a characteristic of coarse, fleshy-rooted trees), and care should be taken to amend the soil, fertilize, water thoroughly, mulch adequately, and avoid Winter salt spray, to enhance survival chances during the first Winter

• Foliage
  • lustrous dark green foliage in Summer, either alternate along the terminal stems or clustered on the many lateral spur shoots
  • five to seven large, pointed, serrated lobes create an overall star-like outline of the leaf blade, which is held on 4" long petioles
  • average to spectacular fall color, often a combination of green, yellow, orange, red, and purple foliage, but sometimes solid crimson, burgandy, or scarlet, coloring relatively late, in late October and much of November

• Flowers
  • monoecious (staminate and pistillate flowers borne on the same tree), flowering in April and May, greenish and ornamentally insignificant, being lost in the emerging foliage

• Fruits
  • trees often do not flower and fruit for the first 15 years or so of their life
  • the spherical and spiny prominent green fruits arise from the lateral spur shoots and are suspended on long peduncles, slowly turning to brown in Autumn
  • the spiny fruits have many "beaks", which open in late Autumn to release the winged small seeds
  • fruits abscise throughout the Autumn, Winter, and following Spring, creating quite a mowing problem on lawns and a litter scenario on lawns, sidewalks, gutters, and culverts

• Twigs
  • stout, with many spur shoots along the main stems and branches
  • great variation exists within the species as to the corkiness of the stems and young branches, which in extreme cases can become quite winged and exhibit a very bold and striking winter outline
  • prominent Winter buds are somewhat large and resinous at each stem terminus, with smaller lateral buds
  • lateral branches are highly symmetrical and dense along the straight trunk in youth, forming a tight narrow pyramidal outline

• Trunk
  • thick bark is brown to medium gray, prominently furrowed and ridged with age
  • the tree slowly loses its strong central leader with age, often due to storm damage of the upper canopy or Winter bud kill of the central leader

• ID Summary
  • strongly pyramidal growth habit in youth, with a straight trunk and highly symmetrical and dense lateral branching
  • star-shaped glossy dark green leaves
  • aggregate and pendulous spiny spherical fruits
  • young stems have some degree of corkiness
  • often has outstanding mixed fall color or scarlet-burgandy fall color
  • large ovoid Winter terminal buds
  • prominent ridges on the thick mature bark

• Function
  • shade, specimen, or focal point tree, often planted for its outstanding fall color

• Texture
  • bold texture when in foliage and bare
  • thick density in foliage but average to thick density when bare, depending upon the degree of stem corkiness

• Assets
  • shiny dark green Summer foliage
  • usually has excellent fall color
  • ornamental fruits (before their abscission that creates a liability)
  • pyramidal growth habit and symmetrical branching in youth
  • rapid growth rate
  • wet site or dry site tolerant

• Liabilities
  • abscised fruits become a litter and mowing hazard
  • iron chlorosis of the foliage may develop in alkaline soils
  • root system can become shallow and surface with age
  • relatively weak wood is prone to storm damage with age and ascending height, and upper canopy buds may die during severe Winters, resulting in loss of the central leader

• Habitat
  • zones 5 to 9
  • native to bottomlands of the Eastern United States

• Alternates
  • shade trees with rapid establishment (Alnus glutinosa, Betula nigra, Fraxinus pennsylvanica, Gleditsia triacanthos, Liriodendron tulipifera, Sophora japonica, Zelkova serrata, etc.)
  • shade trees with excellent fall color (Acer rubrum, Acer saccharum, Fraxinus americana, Quercus rubra, Ulmus parvifolia, Zelkova serrata, etc.)

• Variants
  • Liquidambar styraciflua 'Moraine' - the most cold hardy form (to -25 degrees Fahrenheit), maintaining its pyramidal to upright oval growth habit through maturity, with scarlet fall color

• Translation
  • Liquidambar translates as "liquid amber", referring to the sweet resin that can be obtained from the tree.
  • styraciflua translates as "flowing with styrax" (sweet gum - hence the common name).

• Purpose
  • Sweetgum is a rapidly growing shade tree with lustrous dark green Summer foliage and often having brilliant Autumn coloration.

• Summary
  • Liquidambar styraciflua is known as a pyramidal and rapidly growing shade tree in youth, becoming open and spreading in growth habit with age, and having shiny dark-green Summer foliage that changes to a mixed or crimson fall color, but also having fruits that create a litter problem with age. Its wood is also harvested for use in furniture and plywood.