Links With The Past:  Mulberry Trees And Lancaster’s Silk Industry

Silk Moth Cocoon Mulberry Leaf
Silk Moth

It’s obvious that aged trees can provide links with our past.  In Lancaster’s early years when it was still known as Hickory Town, a young English Elm was carried across the Atlantic and planted “by long-forgotten hands” on a knoll in what is now Woodland Hills Cemetery.  That sapling lived 280 years, offering a connection between 21st Century Lancastrians and those English colonists of so long ago.

The Woodland Hills elm was a venerable old tree when it died, but even seedlings of a short-lived species can remind us of our history.  Mulberry trees grow all over Lancaster County, and usually these trees were not planted by people but instead sprouted up on their own (helped by fruit-eating birds and squirrels, of course).  In the vast majority of cases these trees are not our American Red Mulberry (Morus rubra) but rather the White Mulberry (Morus alba) that is native to northern China.  Why is a Chinese species scattered across Lancaster County when virtually no one is planting it?

The answer dates back at least to Ben Franklin who in 1770 sent a letter to the American Philosophical Society proposing that APS promote the cultivation of White Mulberry trees.  White Mulberry leaves are the preferred food of silkworms, an insect upon which the lucrative silk industry once depended. Early colonists tried feeding silkworms our native Red Mulberry but its leaves are too tough for silk- worm tastes and the resulting silk of rubra-fed ‘worms’ is inferior in quality.  Only White Mulberry will do.  “All persons,” the APS eventually proclaimed, “should be encouraged to cultivate mulberry trees, raise silkworms, and bring their cocoons to the filature.”

It’s hard to exaggerate the importance of the silk industry to Lancaster County in the 19th and early 20th centuries.  In 1838, the Pennsylvania Legislature offered a premium (20-50 cents a pound) for silk produced in the state.  In the 1930s the Stehli Silk Mill (at Martha and Marshall Avenues in Lancaster) employed 2,000 workers and was the largest silk mill in the nation and the second largest in the entire world. For many years mulberry mania gripped Lancaster County and thousands of mulberry trees were planted to support the caterpillars that spewed threads of silk.

The trees were planted in backyards, hedgerows, and even as orchards.  One farmer in Columbia planted an orchard of 30,000 mulberry trees.  Several farmers in Manor Township planted large tracts with thousands of trees and erected huge buildings to house the worms (visitors were awed by “the loud chomping of thousands of caterpillars devouring mulberry leaves”).  There were local newspaper ads like this one:

Dr. W.L. Atlee offers for sale a superior lot of genuine Morus multicaulis trees (a variety of White Mulberry) now growing in the city.  Persons may find it to their advantage to call and see his trees at the corner of East King and Lime Streets.

The industry provided the county with considerable excitement and promised generous profits to its promoters.  Trees were so eagerly sought that unscrupulous “tree agents” sold seedlings that were not always the real McCoy.  Often the fraud wasn’t detected until leaves appeared in spring and mulberries turned out to be maples.

The silk industry prospered for years but bad winters eventually killed the worms and the advent of synthetic fibers doomed silk.  Orchards were uprooted and Stehli Mill finally closed.  Still, White Mul- berry seedlings — descendants of those earlier trees — today appear as “volunteers” all over the coun- ty.  White Mulberry is now so widely naturalized and hybridizes so readily with Red Mulberry, that sci- entists even worry about the long-term genetic viability of our native Red.

But to my point:  Every White Mulberry you see today, however young the tree may be, is a living re- minder of those Lancaster days gone by.  And the berries of this wonderfully prolific tree are, as one newspaper phrased it, the fruit of broken dreams.


Featured Topics

Tree of Heaven’s Better Angels

Tree of Heaven (Ailanthus altissima) is a much maligned, even demonized plant these days. It...

Read More

Measuring Trees

A Word About Measuring Tree Size American Forests, the conservation organization that administers the National Big Tree...

Read More