red mulberry

Photo: Douglas Goldman — CC BY-SA 4.0 · source

Survives zone 4 through 9

Harvest calendar

Best planted in early spring after your last frost, or in fall before the ground freezes, depending on your climate.

Red mulberry — sweet, good-flavored fruit from a fast-growing native tree of eastern North American woodlands; the species is increasingly threatened in the wild by hybridization with introduced white mulberry (Morus alba), which is genetically swamping it across parts of its range.

Hardiness

Zone 4–9

Habit

Tree

Edible part

Fruit

Ripens

June–Aug

Mature size

Tree 8–12 m; dwarf forms containerable

Light

Full sun to partial (woodland-edge)

Soil pH

6.0–7.5 (lime-tolerant)

Environment

Woodland

Native range

Native to eastern North America — from southern Ontario, Quebec and Massachusetts west through the Great Lakes states to Minnesota, Nebraska and Kansas, south to central Texas and Florida. The species is increasingly uncommon to rare across parts of this range — for example in Pennsylvania — substantially because of introgressive hybridization with the introduced Asian species Morus alba (white mulberry). Wind-borne M. alba pollen readily fertilizes M. rubra flowers, producing fertile hybrid swarms that are gradually replacing genetically pure red mulberry in the wild — a documented conservation concern rather than a fringe worry.

Status

Both wild and cultivated

Years to fruit

2–3 yrs

Growth speed

Fast while young — can reach 6–12m within a few years under good conditions — settling to a medium overall rate; trees typically live 125 years or less, with peak seed-bearing between ages 30–85.

Spacing

550 cm (217 in) apart — about 30 m² (326 sq ft) per plant

Leaf shape

Notably variable, even on the same tree — broad, egg-shaped (ovate) leaves with a heart-shaped base, ranging from entirely unlobed to deeply lobed. Lobed leaves occur more often on young shoots and sprouts, unlobed ones more often in the mature canopy; upper surface ranges from rough/sandpapery to nearly smooth.

Root system

Documented as shallow-rooted rather than taprooted, which limits its usefulness for stabilizing disturbed ground; roots are also brittle and best left undisturbed once established, though the tree can spread locally by root sprouts.

Fruit description

A blackberry-like aggregate fruit to about 3cm long, reddish to dark purple — nearly black — when fully ripe; sweet with good flavor, though generally rated milder and less rich than black mulberry. Eaten raw, cooked into preserves, or dried and ground; unripe fruit and the plant's milky sap can cause stomach upset or dermatitis.

Propagation

Grown from seed — cold-stratified in moist sand about 90–120 days near 5°C, germinating in 1–2 weeks after spring sowing — or, more reliably for named selections, from hardwood cuttings (25–30cm, taken dormant) and half-ripe cuttings (7–10cm, July/August); layering also works.

Pollination

Wind-pollinated — because pollen from introduced male Morus alba trees readily fertilizes M. rubra flowers, isolating female trees from white mulberry helps maintain genetic purity when propagating from seed.

The edible parts listed above are a starting point, not a field guide. Identify a plant with certainty — ideally against a local authority — before eating any part of it, and read the full disclaimer. Spotted something wrong? Report it.