'Slender Silhouette' Sweetgum Liquidambar styraciflua 'Slender Silhouette'

'Slender Silhouette' is a tall columnar cultivar of the sweet gum or the Altingiaceae family.  As it matures, it will maintain its erect, uniform, columnar form, growing upwards with the top of the tree about the same width as near the bottom. It will grow to a height of 50 to 60 feet and a width of 5 to 6 feet. The bark is deeply furrowed as the tree ages. The deciduous leaves are star-shaped, and the tree produces fruits that are rounded prickly, woody capsules. Initially, they seem fruitless, but gradually they begin to produce a few fruits. The yields from year to year can fluctuate, but they are much less in number than the species. The fall foliage color is unpredictable, but it may be in shades of yellow, orange, red, or burgundy.

This cultivar was introduced by Don Shadow, a nurseryman from Franklin County, Tennessee, that discovered it growing wild.

The genus name, Liquidambar, originates from the Latin words liquidus which means "liquid," and ambar meaning "amber." This refers to the tree resin. The specific epithet, styraciflua, means "flowing storax" which is a fragrant gum resin. The cultivar name, 'Slender Silhouette,' references the tree's habit.

'Slender Silhouette' is best planted in poor soils and tough spots to insure slower growth and maintain its more narrow habit. If t is planted in ideal conditions, the tree can grow too rapidly and split open. Plant in the full sun, and moist, well-drained soils. Although it is dry soil tolerant when mature, during the first year, the soil should be kept moist without overwatering. Apply a 3-4" layer of mulch around the base to assist the fleshy roots in maintaining moisture as well as to moderate the temperatures.  If pruning is necessary to remove some straggler branches, it should be done in late winter to early spring before the tree leaves out. It has moderate resistance to wind damage.

The cultivar's slender habit makes it ideal for thin or narrow spaces like medians and small gardens as a vertical accent plant. The columnar form also makes it a great choice as a screen or tall planting that borders along property lines. 

Seasons of Interest:

Foliage:  Spring, Summer, and Fall        Fruits: Fall

Quick ID Hints:

• deciduous, tall, narrow, columnar, up to 50 to 60 feet high and 5 to 6 feet wide
• glossy, dark green, star-shaped leaves
• insignificant flowers in the spring
• fluctuating numbers of fruits produced in the fall that are small, round, prickly, woody capsules
• unpredictable fall foliage color

Insects, Diseases, and Other Plant Problems:  'Slender Silhouette' generally has no serious insect pests or disease problems. The leaves can suffer from chlorosis if the soil is too alkaline. It produces very few of the spiny fruits that can cause messes on walkways or injury to bare feet.

VIDEO created by Andy Pulte for “Landscape Plant Identification, Taxonomy, and Morphology” a plant identification course offered by the Department of Plant Sciences, University of Tennessee.

More information on Liquidambar styraciflua.