Morus alba 'Itoguwa' NUCLEAR BLAST
Common Name: white mulberry 
Type: Tree
Family: Moraceae
Zone: 5 to 8
Height: 3.00 to 4.00 feet
Spread: 3.00 to 4.00 feet
Bloom Time: March to April
Sun: Full sun to part shade
Water: Medium
Maintenance: Medium


Best grown in rich, moist, well-drained soils in full sun to part shade. Best in full sun. Prune in late fall or winter to avoid bleeding. Tolerates heat, drought and a somewhat wide range of soils, including alkaline ones. Shallow rooted.

Noteworthy Characteristics

Morus alba, commonly called white mulberry is native to China. It is a rounded, fast-growing, deciduous tree that typically grows to 30-50’ tall and as wide. It usually develops a wide-spreading crown with age. The leaves of this tree have been used in China since at least 2600 B.C. as the primary diet for silkworms used to make silk. Trees were introduced into North America in colonial times in an effort to establish a silk industry. Although the industry never took hold, the trees did take hold and have over time escaped cultivation and naturalized in fields, waste areas, forest margins and along roads throughout much of the U.S. This tree has also been planted in various areas for erosion control and windbreaks. White mulberry is usually dioecious (separate male and female trees), but sometimes is monoecious. Small yellowish-green flowers in drooping catkins bloom in spring (March-April). Fertilized flowers on female trees are followed by sweet, edible blackberry-like fruits (cylindrical drupes to 1” long) that mature in June. Fruits ripen to white or pink, but sometimes to darker reds or purple-blacks. Fruits are loved by birds. Glossy, rounded, usually 2-3 lobed (but sometimes unlobed), dark green leaves (to 8” long) have serrate margins and uneven (sometimes cordate) bases. Glossy leaf surfaces distinguish this tree from red mulberry. Fall color is an unattractive yellow (sometimes green, yellow and brown).

Genus name comes from the Latin name.

Specific epithet comes from the Latin word meaning white in reference to fruit color.

'Itoguwa' is an unusual cultivar of white mulberry that is known as dwarf twisted mulberry or threadleaf mulberry. Its leaves are highly dissected forming a dense tangle of curling, twisted threads up to 2 ft. long on prostrate or pendulous to mounding stems. The celery green to dark green leaves turn a buttery yellow in autumn. It is not known to flower or fruit. It is suitable for container growing, including bonsai. It was discovered and named in Japan. In Japanese ito means thread and ma guwa means harrow. It may be sold under the trade names of NUCLEAR BLAST or ATOMIC BLAST. Given the Japanese origin of this cultivar some people find these trade names offensive.


No serious insect or disease problems. Borers may be a problem particular in the South. Whiteflies mass on some trees. Bacterial blight may kill foliage/branches. Coral spot cankers may cause twig dieback. Bacterial leaf scorch, powdery mildew and root rot may also occur. Watch for scale, mites and mealybugs. Messy fruit may be a concern.


Many gardeners do not consider this tree to have ornamental or fruiting interest. The fruit and resulting bird droppings are messy and will stain pavements, automobiles and areas around the home. Stains may also be unwittingly brought indoors on the bottom of shoes. Species trees often appear unkempt.