Black gum (tupelo)

About Black gum (tupelo)

Black gum, also called black tupelo or sour gum, is a native tree with glossy leaves that turn brilliant scarlet, orange and purple in fall. Its small spring flowers are a prized bee plant for tupelo honey, and female trees bear blue-black fruit that migrating songbirds eat. It has a long taproot, so plant it young in its permanent spot.

Zones 4-9 (NC State).

When to plant

Timing is counted from your average last spring frost (and first fall frost). Sow & Tell works out the actual dates for your ZIP code.

Plant container or balled-and-burlapped trees. Container trees can go in any time the ground can be worked, but fall is the best season in the South because roots keep growing through mild weather (Clemson). Dig the hole no deeper than the root ball and at least twice as wide, keep the top roots level with the soil, and mulch 2-4 inches without touching the trunk. The long taproot makes it hard to move later. You need a female and a male tree for fruit (NC State).

Soil

Moist, acidic soil of clay, loam or sand; it tolerates poor drainage, flooding and some drought, but not alkaline soil (NC State).

Test the soil first. Loosen a wide planting area and mix 10-20 percent compost into the native soil you dig out; don't use uncomposted bark, and don't dig deeper than the root ball (Clemson).

Feeding

• Spring to early summer, after the tree is established, and only if a soil test or pale leaves and weak twig growth show a need: slow-release nitrogen fertilizer with a ratio near 3-1-1 or 3-1-2 (3-0-1 or 3-0-2 if the soil test shows enough phosphorus). Spread it evenly from just outside the trunk flare to the dripline and water it in. Clemson cites 2-4 lb of slow-release nitrogen per 1,000 sq ft per year, split into a spring and a late-summer feeding; follow your soil test.
• Late summer to early fall, the second half of the year's split feeding (only if a soil test calls for it): slow-release nitrogen fertilizer, same as spring. Apply the rest of the year's amount over the root zone and water in. Don't feed a drought-stressed tree in summer (Clemson).

First-year watering matters far more than fertilizer: water daily for the first 1-2 weeks, every 2-3 days until week 12, then weekly, using about 1-1.5 gallons per inch of trunk diameter, until the tree is established, roughly 1.5 years per inch of trunk (UMN). Don't count on rain unless it was over an inch. Plant it young in its permanent spot; the long taproot makes it hard to move. NC State notes watering and feeding speed up its slow growth. Too much fertilizer can burn roots and push soft growth that pests and cold injure (Clemson).

Varieties (9)

NC State documents these cultivars.

Pests to watch for

Leafminers, Scale insects

Diseases and problems

Leaf spot, Canker, Rust, Girdling roots

In the kitchen

The fruit is sour but edible raw or cooked and can be made into preserves (NC State).

Pets: We found no ASPCA listing for black gum.