white mulberry (Morus alba)

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

COMMON NAMES:
Chinese white mulberry
common mulberry
mulberry
white mulberry
Russian mulberry
silkworm mulberry

 

SCIENTIFIC SYNONYMS:
Morus tatarica L.
Morus alba var. tatarica (L.) Ser.

 

CONFIRMATION STATUS: Confirmed.

 

TAXONOMY: The currently accepted scientific name for white mul-
berry is Morus alba L. Some authors distinguish between Morus alba
variety alba (white mulberry), which has white to pink mature drupes,
and Morus alba variety tartarica (Russian mulberry), which has red to
black mature drupes. The latter variety is supposed to have a smaller,
more shrubby habit than the former. The native species, Morus rubra
(red mulberry), is very similar to the introduced species and can hybridize
with it. Red mulberry is a woodland tree with more shade tolerance and
somewhat larger leaves than white mulberry. The upper leaf surface of
red mulberry is usually rough-textured, while its lower leaf surface is often
slightly pubescent between the veins. In contrast, the upper leaf surface of
white mulberry is smooth, while its lower leaf surface is hairless between
the veins. Red mulberry tends to have fewer lobes per leaf (0-3) than
white mulberry, although significant overlap occurs in this trait between
these two species. Like Morus alba var. tartarica (Russian mulberry), red

mulberry has mature drupes that are red or black, although they tend to be
slightly longer than those of Russian mulberry.

 

NATIVE STATUS: Introduced, United States and Canada.

 

GENERAL BOTANICAL CHARACTERISTICS: White mulberry is a
small- to medium-sized, fast-growing, deciduous shrub or tree. As a small
tree, white mulberry can reach a height of 30 - 50 feet. In its cultivated
form, is often coppiced, pollarded or pruned to a low-growing bush to

facilitate the harvesting of fruit or leaves. The trunk is short, thick (8 to 16
inches in diameter, sometimes up to 5 feet) and multi-branched, resulting
in a full, spreading crown, although the crown form can vary from pyram-
idal to drooping. Central stems can grow 20 to 50 feet tall (sometimes up
to 80 feet), but as a weed of roadsides and crop fields, it seldom grows over
15 feet tall. The bark is gray at first, turning an orangish- or yellowish-
brown, with shallow, narrow, scaly furrows or ridges and an orange inner
layer that is visible through the furrows. Secondary branches are generally
slender and, depending on the variety, may be upright or hang casually
toward the ground. Twigs are slender, erect and initially slightly hairy and
reddish-brown, becoming smooth and light orange. Several shoots are pro-
duced from one node, giving the crown a branchy appearance. The ovate
winter buds are reddish brown, bearing grayish brown, imbricate bud
scales that are coated with hairs resembling those on the twig surface. The
thin, bright, light green leaves are alternate, broadly oval (can range from
abruptly acute to obtuse) and 2 to 4 inches long, cordate at their base,
acuminate apices, with toothed margins (triangular teeth). The upper
surface is smooth and shiny. The lower leaf surface is pale green and
enerally smooth, with hairs only along the main veins. Leaves can be
unlobed (common on older trees) or have 2 to 5 unequal lobes (common
on young trees and sprouts from older trees). The petiole (leaf stalk) is
smooth. Both the twigs and leaves exude a milky juice (latex). Clusters of
small petalless flowers are borne in a dense hanging spike. Male and female
flowers are usually produced on separate plants (dioecious), but sometimes
are produced on the same plant (monoecious). The male flower cluster is
narrow and somewhat elongated and the female flower cluster is more
oval. The flowers are held on short, green, pendulous, nondescript catkins
that appear in the axils of the current season's growth and on spurs on old-
er wood. They are wind pollinated and some cultivars will set fruit without
any pollination. Cross-pollination is not necessary. After shedding pollen,
the flowers dry and drop off. The juicy drupelets formed by the individual
flowers on the catkin combine to form a sorosis, the characteristic mulberry
fruit. Fruit colour is commonly black but can vary through light purple to
white – the "white" in the plant’s name refers to its leaf-buds. The juice of
the fruit causes stains which are very difficult to remove from cloth. The
fruit is blackberry like, typically white but sometimes pinkish violet, and so
plentiful it litters lawns and pavements. The tree generally has a deep tap
root with little surface rooting which makes it suitable for use near crop
land. However, white mulberry can produce wide-spreading, aggressive
roots that are known to clog drains.

 

REGENERATION PROCESS: White mulberry propogates itself by
reseeding, generally by wind pollination, but many of the seeds are eated
by birds and dispersed as excrement. In field crops, young trees are cut
off annually by harvesting equipment and sprout new branches each
spring, resulting in a highly branched shrub with a large trunk close to
the ground.

 

SITE CHARACTERISTICS: White mulberry grows well on a wide vari-
ety of soils. It prefers a warm, moist, well-drained loamy soil in a sunny
position. It is not tolerant of shade and rarely grows in forested sites. It
withstands drought once well established. Morus alba is quite salt toler-
ant. This species is also fairly wind-resistant.

 

SUCCESSIONAL STATUS: White mulberry is an opportunistic invasive
that thrives well in early successional stages but generally does not thrive
in more mature forest conditions. While is grows fast, it is short-lived and
does not tolerate shade, making it rare in full forest settings. Successional
information is limited for white mulberry; it typically is encountered in
non-sylvan situations where comparisons with native trees is not applic-
able.

 

SEASONAL DEVELOPMENT: White mulberry flowers from March
to May and fruits from May to August.

 

GENERAL DISTRIBUTION: White mulberry is native to China and
has long been cultivated in Europe. The British introduced it to North
America prior to the American Revolution in a failed attempt to establish
a silkworm industry, since the leaves are the primary food of silkworm
caterpillars. Several varieties of this species have been widely planted in
North America and have become naturalized. Currently Nevada is the
only state not reporting white mulberry. It has yet to be reported from
the Canadian prairie provinces, the northern territories, or the maritime
provinces.

 

SKY MEADOWS DISTRIBUTION:

 

Tree specimens can be found on trails marked in red.

 

       Bleak House
       Appalachian Trail/Old Trail
       South Ridge/North Ridge
       Gap Run
       Snowden
       Woodpecker Lane

       Sherman's Mill
       Rolling Meadows/ Lost Mountain
       Fish Pond

 

HABITAT TYPES AND PLANT COMMUNITIES: In its original
native range, white mulberry occurs naturally in sparse forests on hill-
sides at a wide range of elevations. In the United States and Canada, it
is typically found in minimally maintained public parks and open spaces;
woodlands that develop on abandoned open space; chain-link fence lines;
unmowed highway banks and median strips with frequent salt applica-
tions. It thrives in disturbed areas, roadsides, fields and around buildings.
While it has naturalized in some situations, it is not generally considered
a significant component of any particular plant community.

 

IMPORTANCE AND USES: White mulberry is the food plant of the
moth Bombyx mori (Chinese silkworm), which eats the leaves. This moth
has been thoroughly domesticated and does not exist in the wild. The
larvae of several long-horned beetles (Cerambycidae) bore through the
wood of white mulberry and other mulberry trees, specifically: Dora-
schema alternatum (small mulberry borer), Doraschema cinereum,
Doraschema wildii (mulberry borer), and Parelaphidion incertum (mul-
berry bark borer). Another insect that feeds on white mulberry is the
thrips Pseudodendrothrips mori, which sucks juices from the leaf under-
sides. The juicy drupes of white mulberry are readily eaten by many
species of birds. Interestingly, the drupes are also eaten by Terrapene
carolina (eastern box turtle) and Terrapene ornata (ornate box turtle).
Among mammals, the drupes are eaten by the opossum, raccoon, fox
squirrel, and gray squirrel; white-tailed deer browse on the leaves and
twigs, while beavers gnaw on the wood. While relatively few insects feed
on white mulberry, the value of this tree to vertebrate wildlife is quite high.

White mulberry leaves are eaten as a vegetable and are useful as a cattle
fodder. Wild birds, hogs, and poultry eat the mulberry fruit.

 

White mulberry is used in tree strips for windbreaks. They are also planted

and managed to protect livestock, enhance production, and control soil

erosion. However, the ecological threats posed by white mulberry are con-

siderable and include its hybridization with and replacement of our native

red mulberry (Morus rubra), the transmittal of a harmful root disease to

red mulberry, and its ability to invade natural areas including fields, forest

edges and roadsides.

 

White mulberry was introduced along the Atlantic seaboard during colonial
times when an attempt was made to establish the silkworm industry in this
country. A fiber was obtained from the bark and used in weaving. A brown
dye can be obtained from the trunk.

 

The wood is valued for sporting goods due to its durability, flexibility, and
elasticity. It is used mainly for tennis and badminton rackets, hockey sticks,
furniture, agricultural implements, and house and boat building materials.

The stem is fibrous and is used in Europe and China for making paper.

 

The leaves are taken internally in the treatment of sore throats, colds, eye
infections, and nose bleeds. The stems are used in the treatment of spasms,
rheumatic pains, and high blood pressure. The fruit is used in the treatment
of urinary incontinence, dizziness, diabetes, pre-maturing gray hair, and
constipation in the elderly.

 

The fruits may be eaten cooked or raw and are made into jellies, jams, pies
and is added to bread, cookies, or puddings. The fruit is also an ingredient
in mulberry wine and is used as a raisin substitute. The inner bark was
roasted and grounded into a meal and then used as a thickener in soups or
mixed with cereals when making bread. The young shoots were used as a
tea substitute.

 

 

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