Here's what the great font of knowledge has to say on the subject:
A bathtub madonna, bathtub Mary, or bathtub shrine is an artificial
grotto containing a statue of the
Blessed Virgin Mary, constructed by upending an old
bathtub and burying one end. It is a form of
yard shrine (a shrine built in one's
yard). The grotto is sometimes embellished with
brickwork or
stonework, and with
flowerbeds and small figures of animals meant to demonstrate Mary's affinity with
God's creation. The inside of the tub is frequently painted a light blue color. The term is also used to refer to other yard shrines which are not constructed from actual bathtubs. Bathtub madonnas are most frequently placed in the front yards of homes of
Roman Catholics, especially by Catholics of
German heritage. Although statues of other
saints or of
Jesus may be enshrined, the usual subject is Mary. Bathtub madonnas greatly resemble the
side altars (
Lady chapels) found in some Catholic churches.
Over time, distinguishing characteristics of these shrines can become blurred. Instances inevitably occur of shrines whose statue is missing (creating a bathtub with no Mary) and conversely of grottoes being removed, leaving a statue in place.
Locations
Bathtub Marys in actual bathtubs are frequently found in the upper
Mississippi River valley, including eastern
Iowa, western
Wisconsin, and
Minnesota, and are an important part of the visual
folk culture of Roman Catholics in that region. A noteworthy concentration of bathtub madonnas occurs in
Stearns County, Minnesota, an area heavily settled by German Catholics in the 19th century.
Google and magazine database searches reveal instances of bathtub shrines among other Catholic
ethnic groups in other locations, e.g.,
Mexican Americans in
Milwaukee,
Italian Americans in
Michigan, and
Hispanic Americans in
New Mexico.
In the northeastern United States, smaller shrines that do not make use of actual bathtubs are more common.
Somerville, Massachusetts, a city which has traditionally had sizable
Italian,
Irish and
Portuguese/
Brazilian populations, has a very large number of smaller shrines; well over 200 Catholic yard shrines in a town of about four square miles, with only one example using an actual bathtub.
Bathtub madonnas are also a common sight in north-central
Kentucky, an area that has historically been predominately Catholic. A drive down country roads in
Nelson,
Marion, and
Washington counties will provide ample sightings of these small shrines. Bathtub shrines can also be seen in Québec.
[
edit] References
"For the Love of Mary — Yard Shrines Honoring Blessed Virgin Have Devoted Following," St. Cloud Visitor (Newspaper of the Roman Catholic Diocese of St. Cloud, Minnesota), August 16, 2001.
Miyazaki, Kevin J., "Our Town" (feature on bathtub shrines among Mexican immigrants), Milwaukee Magazine, Vol. 28, No. 1, January 2003, p. 20.
Perera, Srianthi, "Grave Images Illuminate 150-year Tradition," The Arizona Republic, Vol. 116, No. 339, April 22, 2006, p. CR-18.
In my internet searches, I have also found that a lady at the University of Wisconsin-Milwaukee wrote a thesis on bathtub shrines in 1994. I'm trying to get access to it via interlibrary loan, so we'll see what happens with that.