The black gum (Nyssa sylvatica) is a deciduous tree that is originally from the United States. It is favored for its brilliant fall foliage and its winter form, which displays attractively dropping branches over time. Black gum is an excellent choice to add autumn color to your garden.
Nyssa sylvatica has dark green leaves that are ovate, obovate, or elliptical and measure 3 to 6 inches long. The fall display includes foliage in shades of orange, red, purple, and yellow. The flowers of black gum are light green in color and form into pendulous clusters in the spring.
The names used for this tree are black gum, sourgum, yellow gum, black tupelo, cotton gum, tupelo-gum, pepperidge, swamp tupelo, swamp black gum, sour gum or tupelo. This tree is not related to gum trees, which belong to Angophora spp., Corymbia spp. and Eucalyptus spp.
- Botanical name: Nyssa sylvatica
- Common name: Black gum tree
- Plant type: Tree
- Mature size: 75 feet tall and 30 feet wide
- Sun exposure: Full sun to partial shade
- Soil type: Loamy or clay
- Soil pH: Acidic
- Bloom time: Spring
- Flower color: Light green
- Hardiness zones: 4 to 9
- Native area: Eastern United States
How to Grow Black Gum Trees
Since the black gum has a long taproot, it can have difficulties after it is transplanted. It also may struggle if planted in the fall. For best results, you may want to start one from seed in the desired site or choose a young sapling where the taproot will be shorter.
The mature height of the black gum can be 30 to 75 feet tall and 20 to 35 feet wide, depending on the growing location and climate. When the black gum is young, it is usually formed into a pyramidal shape. Over the years it can be oval, irregular, or horizontal in shape.
Black gum trees generally are deciduous, so you would need both a male and a female for fruit production. Sometimes, however, the tree can grow perfect flowers, making this ultimately a polygamodioecious species. Once the flowers are pollinated, they form into black stone fruits (drupes) that mature in early fall. Birds will eat the fruits, but they are not desirable for human consumption.
The black gum should be planted where there will be full sun to partial shade.
Nyssa sylvatica needs soil that is acidic and that allows water to drain away from the roots.
Nyssa sylvatica prefers moist soil and can grow in standing water.
Temperature and Humidity
Being native to the eastern United States, this tree adapts to extreme climates, tolerates wet conditions, and is drought-resistant.
Black gum trees are relatively slow growing but will respond well to applications of fertilizer in the fall. Sprinkle the fertilizer on the soil under the tree to 1 1/2 times the distance from the trunk to the drip line (tips of the branches). The general rule is two cups of slow-release granular fertilizer for every inch of diameter of the trunk measured four feet above the soil surface.
Reproduction is performed through seed germination and the use of cuttings. Grafting is used to preserve the characteristics of named cultivars.
- ‘Zydeco Twist’ is a variety of black gum that offers branches that twist somewhat and stand out during the winter.
- ‘Autumn Cascades’ is a weeping variety with especially good fall coloring.
- ‘Wildfire’ will produce red leaves throughout the growing season.
Black gum does not usually require much pruning to maintain the tree beyond the standard care of removing parts that have become dead, damaged, or diseased.
Common Pests and Diseases
Black gum is vulnerable to specific pests and a few common diseases:
- The forest tent caterpillar (Malacosoma disstria) will chomp away at the leaves and cause defoliation. You can try organic controls like Bacillus thuringiensis var. kurstaki, neem oil, and spinosad. You can also remove affected branches to get rid of nests and eggs. If the problem persists and is extensive, call your local extension service to find appropriate insecticides for your area.
- Sapsuckers are a type of bird that peck holes into the trunk to reach the sap. You can wrap the areas of the trunk where they attack in burlap, or you can use a deterrent that is formulated for sapsuckers.
- Insect pests include sourgum scale (Chionaspis nyssae) and other scales and tupelo leafminer (Antispila nysaefoliella).
- Cankers can result when fungi start growing on a dead branch. Take out the affected branch to help curb the spread of the fungus.
- Heart rot occurs after a tree has had open wounds occur in the trunk. Fungi invade and, over time, cause the wood to rot and decay. You will need to watch the tree over time to see how extensive the damage becomes.
- Black gum is susceptible to leaf spots caused by a fungus. Raised leaf spots appear on the leaves and begin to discolor and drop off. While it's mostly cosmetic, it can make the tree more attractive to other pests and diseases.
- Tupelo lesion happens when the Fusarium solani fungus attacks, resulting in the bark swelling up and becoming rough.