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// SPECIES PROFILE · TREE · EDIBLE · NATIVE

Red Mulberry

Morus rubra

Red Mulberry is the sweet secret of the bottomland forest — a medium to large native deciduous tree whose branches hang heavy with juicy, dark-purple aggregate fruits in late spring and early summer, weeks before most other fruit trees have even thought about ripening. Morus rubra is the native North American mulberry, a species of rich, moist woods from the Midwest to the Atlantic and south into the Cross Timbers of Oklahoma. Its fruits are among the most eagerly consumed wild foods in the eastern forest, drawing over 50 species of birds, and the tree itself is a larval host for the mourning cloak butterfly. In a NE Oklahoma food forest, Red Mulberry fills the critical niche of a shade-tolerant, mid-canopy fruit producer — one of the few trees that will bear heavily in the dappled light beneath taller pecans and oaks.

// QUICK FACTS
Family
Moraceae (mulberry / fig family)
Life cycle
Deciduous tree; long-lived (50–100+ years)
Native range
Eastern and central US — MA to FL, west to MN, NE, OK, TX
USDA hardiness
Zones 4–9 (Tulsa = 7a/7b)
Mature size
35–50 ft tall (up to 70 ft), 35–40 ft wide; rounded, spreading crown
Bloom
April – May
Fruit ripening
Late May – July (NE OK); among the earliest tree fruits each year
Sun
Part shade to full sun; tolerates understory conditions
Soil
Rich, moist, well-drained; prefers bottomland and riparian soils; pH 5.5–7.5
Water
Medium to moist; tolerates occasional flooding
Wildlife
Fruit for 50+ bird species · mourning cloak butterfly host · mammal browse · nesting structure
Edible
Fruits eaten fresh, in pies, jams, wines; sweet, juicy, distinctive flavor
Red Mulberry (Morus rubra) showing variable leaf shapes and ripe dark-purple fruit
Morus rubra in fruit — the ripe aggregate fruits are juicy, sweet, and dark purple, held on short stalks along the branches. Photo: Rooted Revival.

Identification

[ field key — bark · leaf · flower · fruit · distinction from white mulberry ]

Form & Bark

A medium to large deciduous tree with a broad, rounded, spreading crown. The bark is distinctive: on young trees and branches it is smooth and grayish-brown with prominent orange-brown lenticels; on mature trunks it develops into long, narrow, scaly ridges with a reddish-brown to orange-brown under-bark visible in the furrows — this warm, orange-brown color in the bark fissures is a key field mark for distinguishing M. rubra from the paler, grayer bark of the invasive white mulberry (M. alba). Young twigs are slender, reddish-brown, and bear a milky sap when broken.

Leaves

Alternate, simple, broadly ovate, 3–8 in long, with a serrate (toothed) margin. The leaves are highly variable in shape even on a single tree: they may be unlobed, 2-lobed (mitten-shaped), or 3-lobed, with the lobed forms more common on vigorous young shoots and saplings. The upper surface is dark green and rough (scabrous) with a sandpapery texture; the lower surface is softly pubescent (hairy) and paler green. This rough upper / soft lower leaf surface is the best way to distinguish M. rubra from M. alba, which has smooth, glossy leaves on both surfaces. Fall color is a clear, soft yellow.

Flowers

Red Mulberry is dioecious or occasionally monoecious (male and female flowers usually on separate trees, sometimes on the same tree). Flowers appear in April–May as the leaves emerge. Male flowers are borne in pendulous, greenish-yellow catkins 1–2 in long, producing abundant wind-dispersed pollen. Female flowers are shorter, denser, greenish catkins that develop into the fruit. Flowers are wind-pollinated and inconspicuous; the tree is not insect-pollinated. A single male tree can pollinate several female trees at considerable distance. Only female trees produce fruit.

Fruit & Distinction from White Mulberry

The fruit is a syncarp (aggregate fruit), 1–1.5 in long, composed of many small drupelets clustered around a central core, resembling an elongated blackberry. Fruits ripen from green through red to deep purple or nearly black in late May through July, and they are sweet, juicy, and richly flavored. Distinction from white mulberry (Morus alba): M. rubra has rough upper leaf surfaces, soft-hairy lower surfaces, longer fruit stalks (peduncles), and consistently dark purple, sweeter fruit. M. alba has smooth, glossy leaves on both surfaces, shorter fruit stalks, and variable fruit color (white, pink, red, or purple) with generally blander flavor. The two species readily hybridize, and intermediate forms are common in disturbed habitats.

Habitat & Range in NE Oklahoma

Morus rubra is native across the eastern and central United States, from Massachusetts and Vermont south to Florida, and west to Minnesota, Nebraska, Oklahoma, and central Texas. In NE Oklahoma it is a characteristic species of rich, moist bottomland forests, river bottoms, and riparian corridors along the Arkansas, Verdigris, and Neosho River systems. It also occurs in the moister draws and north-facing slopes of the Cross Timbers, where deeper soils and higher humidity create suitable conditions beneath post oaks and hickories.

The species shows a strong preference for mesic, nutrient-rich soils and is much less common on dry, rocky upland sites. It tolerates considerable shade as an understory tree, often persisting and fruiting (though with reduced yield) beneath a canopy of taller hardwoods. This shade tolerance, combined with its relatively small mature size, makes it one of the most useful native fruit trees for the lower canopy layer of a multi-story food forest. In the wild it is frequently found alongside sycamore, hackberry, boxelder, green ash, and pecan in the rich alluvial soils of NE Oklahoma's river valleys.

Ecology & Wildlife Value

[ fruit for birds · butterfly host · mammal food · riparian role ]

Fruit for Birds

Red Mulberry fruits are among the most important soft mast resources for eastern forest birds, and the tree has been documented feeding over 50 bird species. The fruit ripens in late spring/early summer, at a critical time when birds are feeding nestlings and energy demands are high. Key consumers include Northern cardinals, American robins, cedar waxwings, brown thrashers, gray catbirds, Eastern bluebirds, wood thrushes, Baltimore orioles, great crested flycatchers, red-bellied woodpeckers, and several warbler species. The high sugar content makes mulberries a preferred fruit for migratory songbirds refueling during spring migration.

Mourning Cloak Butterfly Host

Morus rubra is a larval host plant for the mourning cloak butterfly (Nymphalis antiopa), one of the earliest butterflies to emerge each spring — you will see them flying on warm February days. The caterpillars are spiny, black with white speckles and a row of red dorsal spots, and feed gregariously on the foliage. The tree also hosts larvae of the Io moth (Automeris io) and several other silk moths. The foliage is wind-pollinated so it does not attract pollinators, but the fruit-laden branches draw insects that feed on fallen and fermenting fruit.

Mammals & Seed Dispersal

The fruit is consumed by raccoons, opossums, foxes, squirrels, and white-tailed deer. These mammals are important seed dispersers, carrying seeds away from the parent tree and depositing them in droppings that provide a nutrient-rich microsite for germination. The foliage is browsed by deer, though it is not preferred. Beavers feed on the bark and branches along waterways.

Conservation Concern: White Mulberry Hybridization

The single greatest threat to Morus rubra is hybridization with the invasive white mulberry (Morus alba). White mulberry was introduced from Asia in the 17th–18th centuries for silkworm culture and has spread aggressively across North America. The two species hybridize freely, and in many regions pure M. rubra is becoming increasingly rare, replaced by hybrid swarms. M. rubra is listed as endangered or threatened in several northern states for this reason. In NE Oklahoma, planting pure M. rubra from verified sources and removing weedy M. alba from the landscape are conservation actions with direct positive impact.

Food forest role: Red Mulberry is one of the best native fruit trees for the understory or mid-canopy of a multi-story food forest. It tolerates partial shade, produces heavily once mature, and drops its fruit over a period of several weeks (a "staggered harvest" that spreads the bounty for both humans and wildlife). Plant on the north or east side of taller trees for dappled light, or as a stand-alone specimen in full sun for maximum production.

Horticulture & Care

[ site · planting · pruning · harvest · cultivars ]

Site selection & planting

Red Mulberry prefers rich, moist, well-drained soil in a site with full sun to part shade. It is more tolerant of shade than most fruit trees, making it valuable for woodland-edge and understory plantings. However, full sun produces the heaviest fruit yields. Plant container-grown or bareroot trees in late winter or early spring. Provide regular water through the first two growing seasons. The tree has a moderate to fast growth rate and may begin fruiting in 5–8 years from seed; grafted or cutting-propagated trees often fruit earlier.

Pruning & maintenance

Prune in late winter during dormancy. Red Mulberry bleeds milky sap from pruning cuts, which can be messy but is not harmful to the tree. Establish a central leader and well-spaced scaffold branches in the first 5–10 years. Remove dead, damaged, and crossing branches annually. Mature trees need little pruning beyond dead wood removal. Do not top or severely head back mulberries; they respond with a flush of weak, poorly attached watersprouts. Apply a 3–4 in layer of organic mulch over the root zone, keeping it away from the trunk.

Pests & diseases

Harvest & selection

Fruit ripens over several weeks from late May through early July in NE Oklahoma. Ripe fruit is dark purple, soft, and detaches easily. The traditional harvest method is to spread a tarp or sheet beneath the tree and shake the branches; ripe fruit falls readily. For clean fruit, pick by hand gently — the fruits are perishable and fragile. Fresh mulberries keep only a few days refrigerated; freeze or process promptly into jam, syrup, pie filling, or wine.

Notable selections

Selection Type / origin Distinguishing feature Notes for Tulsa
'Illinois Everbearing' M. alba × rubra hybrid Long harvest window (8–12 weeks); large, sweet, dark fruit Most widely planted mulberry; excellent fruit; note it is a hybrid, not pure M. rubra.
Wild M. rubra (female) Pure native species Deep purple, sweet, richly flavored fruit; largest leaves Sourced from native nurseries or grown from wild-collected seed. Pure genetics are increasingly rare.
'Hicks' Pure M. rubra selection Selected for heavy fruit production; disease-resistant Excellent choice for pure native planting.
'Travis' Pure M. rubra selection Very large fruit; selected in Texas Well-adapted to southern Plains climate.
Source carefully: Many nurseries sell Morus alba or hybrids labeled simply as "mulberry." If you want true native Morus rubra, purchase from a reputable native plant nursery that verifies their stock. The rough upper leaf surface and hairy lower leaf surface are the best field characters for confirming identity.

Edible & Cultural Uses

Red Mulberry has been a valued food source across eastern North America for millennia. Archaeological evidence documents its use by Indigenous peoples from the Archaic period onward, and the tree was actively managed and planted near settlements throughout its range, including by the Osage, Caddo, and Cherokee peoples whose territories included what is now Oklahoma.

Harvesting tip: The easiest and most traditional method is the "tarp and shake" — lay a clean tarp or old sheet under the tree, shake the branches, and collect the fallen fruit. This also harvests the ripest berries, leaving the unripe ones for the birds and a second harvest a few days later.

Sources & Further Reading

  • USDA NRCS PLANTS Database — Morus rubra: plants.usda.gov/plant-profile/MORU2
  • Lady Bird Johnson Wildflower Center — Native Plant Database: wildflower.org — MORU2
  • Wikipedia — Morus rubra: en.wikipedia.org/wiki/Morus_rubra (CC BY-SA 4.0; portions of description and uses summarize Wikipedia content).
  • Missouri Department of Conservation — Red Mulberry field guide: mdc.mo.gov
  • Moerman, D.E. (1998). Native American Ethnobotany. Timber Press.
  • Dirr, M.A. (2009). Manual of Woody Landscape Plants: Their Identification, Ornamental Characteristics, Culture, Propagation and Uses. Stipes Publishing.

Hero photo: Rooted Revival.