Tree · Moraceae
Mulberry
Morus rubra
Give it sun and open room to spread, and the mulberry hangs heavy with fruit, buckets of it, every early summer.
Full sun
Every 7–21 days
USDA 4–9
25–60 ft · 7.6–18.3 m
Overview
A mulberry grows into a broad, fast-spreading tree hung with sweet, blackberry-like fruit. It sits in the fig family and climbs to 25 to 60 feet (7.5 to 18 m) tall, its wide crown branching low and full. The fruit ripens in early summer to the deep red and near-black of a blackberry, soft and juice-filled on the stem, and the red mulberry native to the eastern US wears dull, matte leaves while the white and black species from Asia carry their own leaf textures.
Look closely and the mulberry shows its two faces. It is hardy enough to hold its form through cold as low as -29°F (-34°C), it stands through drought once grown, and it fruits so thickly that the berries drop and burst, staining pavement a deep purple. Birds strip the crop and scatter the small seeds far and wide, so where the tree stands matters as much as how it is grown.
Given the right ground, a mulberry fills out into a dense, long-lived tree that asks for little. Full sun, deep soil, and space clear of patios and paths let its heavy crown spread for decades. Note that the white mulberry, with its glossy leaves, has turned invasive across much of the US, so the matte-leaved native red mulberry or a named cultivar is the safer pick.
Care
The short version: deep, well-drained soil, full sun, and space for a wide crown. Water it in its early years, prune it only in hard winter, and keep it back from anything the dark, juicy fruit could stain.
Light
The fruit sets thickest in full sun, though the tree takes partial sun or light shade. More light also holds the crown open and airy, so the leaves dry fast after rain and shed the white bloom of mildew.
Water
A young tree wants a deep drink about once a week while its roots reach down. Once grown, a mulberry is quite drought tolerant, its thick roots pulling through all but a long dry spell.
Soil
It roots best in deep, well-drained loam dark with organic matter. It endures heavy clay or loose sand but thins and sulks in poor, shallow ground, and it takes to soil across a pH of 5.5 to 7.5.
Temperature
The wood is remarkably hardy, holding through cold to -29°F (-34°C) and heat up to 104°F (40°C). That span carries it across USDA zones 4 through 9.
Humidity
Ordinary outdoor air of about 30% to 70% humidity suits the leaves fine, with nothing to manage. Moving air through the crown does more than any figure, drying the broad leaf surfaces that mildew would otherwise coat.
Feeding
A mature mulberry rarely needs feeding, and its wood often fruits better lean. A pale, sluggish young tree takes a light balanced fertilizer or compost in early spring, no more, since overfeeding forces soft, floppy, weak growth.
Pruning
The cuts run with sap unless the tree is fully dormant in late winter, so that bare-branched window is the time to work. Take out dead, crossing, or crowded limbs, shape the young frame, and keep every cut under about 2 inches across so the wound closes clean.
Repotting
As a heavy landscape tree rooted in the ground, a mulberry is not repotted. A young or container-grown tree moves only while it is dormant and bare, and roots circling the pot or growth that stalls in spring are the signs it needs the shift.
Size & spacing
This is a large tree, 25 to 60 feet (7.5 to 18 m) tall with a broad crown spreading 35 to 40 feet (10.5 to 12 m) wide. It needs that much open ground, its low, heavy branches held well clear of buildings, paths, and other plantings.
When to plant
The mulberry moves through the year in clear stages. A young tree settles in when planted in spring after the frost, or in fall while its branches stand bare and dormant. Small flowers open across April and May, and the fruit swells and darkens through May and June, hanging on into summer on some types.
Northern hemisphere
Southern hemisphere
Typical months for a temperate climate: start earlier in warm zones, later where spring frosts linger.
- Plant: Spring after the last frost, or in fall while the tree is dormant
- Harvest: Blooms April-May; fruit ripens roughly May-June (into summer for some types)
Hardiness
USDA hardiness zones: 4–9
Temperature: down to -34°C
Troubleshooting
A mulberry is a sturdy, thick-limbed tree, so most of its trouble is mess and pests rather than deep disease. Watch the bark of the trunk for borers, the surface of the leaves for a white film, and the ground for purple stains and thin green seedlings. Match the sign below, then act while the job is still small.
Sagging branches over sawdusty grit and holes in the bark
When a limb droops and its leaves go limp, look low on the trunk for the mark of a borer: neat round exit holes, dark ooze weeping down the bark, and a scatter of powdery, sawdust-like frass at the base. Cut the tunneled limbs away and burn them, then keep the tree strong with steady water and mulch so it can seal off the next grub. Fresh, torn bark is what draws the egg-laying beetle, so keep mowers and trimmers from ever scraping the trunk.
Fix:
- Prune out and destroy infested limbs
- Keep the tree vigorous with proper water and mulch
- Avoid bark wounds that invite egg-laying
A floury white crust dusting the foliage, late summer
By late summer a chalky white bloom can dust the leaves, and it is powdery mildew, a surface fungus that smears off under a wiping finger and clings to both the top and the underside of the blade. It leaves little real damage on a full-grown tree. Thinning the crowded, shaded growth lets air slip through and dry the leaves, while raking the fallen ones off the ground clears away the spores. Full sun and dry foliage keep the white film from settling back in.
Fix:
- Improve air circulation by thinning crowded growth
- Rake and remove fallen infected leaves
Purple-blotched paving and small seedlings dotting the ground
The heavy crop of soft, juice-filled berries is the source of the mess: they burst where they land and bleed a deep purple into the pavement, and birds carry the tiny seeds off to sprout in beds and lawn. Tug the young volunteers out while their roots are thin, and clear the squashed fruit before the stain sets. Since the fruit is the tree's nature, placement is the true remedy, so set a fruiting tree well back from patios, driveways, and walkways, and turn to a fruitless cultivar only where pollen-allergy rules allow.
Fix:
- Hand-pull volunteer seedlings while young
- Site away from patios, driveways, and walkways
- Choose a fruitless cultivar only where allergy bans do not apply
Toxicity
The soft, dark ripe berry is a sweet, safe fruit for people and pets, which is the heart of the tree's appeal. The trouble sits in the rest of it. The hard green unripe fruit and the milky white sap that beads from cut leaves and stems can sting skin and unsettle a stomach, so keep grazing animals and curious children away from the green parts.
Safe for
People · Cats · Dogs · Horses · Rabbits · Livestock · Birds
Cats Mild
The dark, ripe berries do a cat no harm. The white, milky sap and the hard green unripe fruit are the culprits, and at worst they leave a cat drooling or bring on a short bout of vomiting, kept minor by light chewing.
Dogs Mild
A dog handles the soft ripe fruit with ease. A mouthful of firm green berries or a chew on the sap-beaded leaves is what brings soft stools or a little vomiting, and that clears on its own.
Horses Mild
Squashed ripe windfalls are fine for a horse in moderation. Browsing leaves still weeping sap, or nipping the green fruit, is what loosens the gut and dulls the appetite for a day or so.
Rabbits Mild
A few soft ripe berries make a safe treat for a rabbit, though its gut is delicate, so the green unripe fruit and the sappy leaves can bring on loose stools. A small portion and a watchful eye keep it easy.
Livestock Mild
Cattle, goats, and sheep clean up fallen dark mulberries without harm. A big feed of green fruit or sap-laden leaves can loosen the gut into passing diarrhea, and in real quantity the unripe berries can act as a mild intoxicant.
Birds Mild
Birds strip the ripe, dark berries clean and come to no harm, which is half the reason the seed travels so far. Only the hard green, unripe fruit might unsettle a stomach.
People Ripe fruit safe
The soft, dark ripe mulberry is a sweet, safe fruit eaten fresh or baked. The firm green berries and the milky white sap are the ones to skip, since the sap can irritate skin and, in quantity, upset the stomach or even cause hallucinations.
Ripe berries are safe, but unripe green or white berries and the milky sap of leaves and stems can cause mild gastrointestinal upset, and the sap is a mild skin and GI irritant.
Varieties
Three species and a few hybrids cover most of what you will find for sale, and they differ in leaf sheen and fruit color and size. Knowing those marks apart helps you pick the right tree and avoid the invasive one.
Morus rubra (red mulberry)
Native to the eastern US, it wears dull, matte, non-glossy leaves and ripens fruit in dark red to purple.
Morus alba (white mulberry)
Carried from Asia for silkworms, it shows bright, glossy leaves and has turned invasive across much of the US, where it crosses with the native red mulberry.
Morus nigra (black mulberry)
It bears the largest, deepest, richest-flavored fruit of the three, though it is the least cold hardy.
Illinois Everbearing
A productive cross of M. alba and M. rubra, this cultivar sets fruit over a long, heavy season.
Companions
A mulberry works best as a decoy for hungry birds and worst as a neighbor to anything that needs sun or clean ground beneath it.
Plant near
Cherries and blueberries: Birds strongly prefer mulberries, so a mulberry can act as a decoy that draws them away from other fruit crops.
Clover or other low groundcover: A living groundcover suppresses weed seedlings and adds organic matter under the canopy.
Keep apart
Vegetable and flower beds: Dense shade, greedy shallow roots, and staining fruit drop make underplanting and nearby beds difficult.
How to propagate
A mulberry grows on from a cutting, a graft, or a seed, and the route you take depends on whether you want a faithful copy of a named tree or simply more trees.
Stem cuttingsEasy
Hardwood cuttings in late winter; softwood cuttings in early summer · About 4-8 weeks to root
Bare, woody hardwood cuttings taken in late winter, or green softwood cuttings in early summer, will push out fresh white roots in about 4 to 8 weeks. White mulberry roots eagerly from these, while red and black mulberry are slower and more stubborn to strike.
GraftingModerate
Late winter to early spring (whip or bark graft) · One growing season
Grafting joins a named fruiting cultivar, or a species that resists rooting, onto tough seedling rootstock, binding scion and stock together. The whip or bark graft is set from late winter into early spring, and the union knits and swells over a single growing season.
SeedModerate
Sow after 1-3 months of cold stratification · Several years to first fruit
The tiny seeds need 1 to 3 months of cold stratification before sowing, and the seedling that follows takes several years to fruit. The young trees come out variable, no two quite alike, and white mulberry in particular self-seeds hard wherever birds drop the dark fruit.
Myths
A fruitless male mulberry gives a clean, problem-free shade tree.
Fruitless simply swaps one mess for another that you cannot see. The male trees, usually Morus alba, shed enormous clouds of fine allergenic pollen, and some cities such as Albuquerque restrict or ban them outright to protect air quality.
The mulberry is poisonous from leaf to berry.
It is not. The ASPCA lists mulberry as non-toxic, and the ripe fruit is good to eat. Only the hard unripe berries and the milky white sap cause trouble, and even then it is a mild, short-lived stomach upset.