Dwarf Lake Iris (Iris lacustris)
Distribution & Habitat
How You Can Help
Did You Know…?
Distribution & Habitat
This miniature iris grows nowhere else in the world but in the Great
Lakes Region. Most of the world's Dwarf Lake Iris population lies within
Michigan's boundaries. It is known outside of Michigan only from Manitoulin
Island and the Bruce Peninsula in Ontario, and the Door Peninsula of Wisconsin.
It formerly grew near Milwaukee, Wisconsin. In Michigan, Dwarf Lake Iris is
especially concentrated along certain stretches of the northern Great Lakes
shoreline, where it may occur for miles, interrupted only by habitat
destruction, degradation, or unsuitable habitat such as rocky points or marshy
Dwarf Lake Iris usually occurs close to the Great Lakes shores on sand or in
thin soil over limestone rich gravel or bedrock. It tolerates full sun to near
complete shade, but flowers mostly in semi open habitats. These areas can be
very long and narrow strips bordering the high water line, or large flat
expanses located behind the open dunes of the Great Lakes shoreline. Many iris
locations are on old beach ridges of former shores of the Great Lakes.
Fluctuating water levels of the Great Lakes play a vital role in opening up new
habitat for Dwarf Lake Iris. During high water years, trees and shrubs along the
shoreline may be flooded out. This flooding may open up patches within the
forest where the Dwarf Lake Iris may spread. It is usually found growing under
White Cedar, although White Spruce, Balsam Fir, and Aspen are also frequently
present. Other plants commonly growing with Dwarf Lake Iris include the lovely
deep pink flowered Gay wings, white Starry False Solomon seal, and the brilliant
orange red Indian Paintbrush.
Dwarf Lake Iris can be distinguished from other native iris species in
Michigan by its very small size, and its thin, shallow, yellow rhizomes or
underground stems. The slender rhizomes produce fans of flattened leaves that
reach a height of about 6 inches. The leaves are light green and usually not
more than 1/2 inch wide. Showy, deep blue flowers are produced singly on short
stems, below the height of the leaves. It can grow in very large, dense,
patches, forming a carpet of blue flowers from mid May to early June. A white
flowered form is known from several locations in the Mackinac Straits Region and
elsewhere. When the plant is not in flower, it can be confused with False
Asphodel, a white flowered member of the lily family whose leaves are much
narrower. The flower stalk of False Asphodel is much longer than that of iris
and very sticky.
Dwarf Lake Iris is found only on the northern Great Lakes shoreline of Lakes
Michigan and Huron. It is threatened by loss of habitat due to increased human
activity along the shoreline. Human disturbance such as shoreline development
and intensive recreation are major threats. Dwarf Lake Iris is listed as a
"threatened" species by the federal government and the state of Michigan. A
permit is required for any project (including research, development, and
construction) which may "take" or "harm" threatened or endangered species in
In addition to aesthetic, ethical, and ecological reasons for protecting
Earth's diverse species, another reason can be offered: selfinterest. The
natural world is our life support system, providing countless medical,
agricultural, and commercial benefits. For example, chemicals from plants are
the sole or major ingredient in one quarter of all prescription medications in
the United States. Scientists have shown that closely related plants usually
have similar chemical components. The Yellow Flag, an iris native to Europe that
has occasionally escaped from cultivation, has been used as a source of black
dye and ink. If we choose to save wild species now, they may offer opportunities
for us in the future. We do know that when a species becomes extinct, a unique
set of genetic material whose use presently may be unknown, is lost forever.
To conserve the remaining populations of Dwarf Lake Iris, private, corporate,
and public landowners and land managers who are likely to have Dwarf Lake Iris
on their Great Lakes shoreline property are being contacted. Landowners have the
opportunity to assist in the preservation of this remarkable component of
Michigan's natural heritage. Other cooperative conservation efforts initiated by
the Natural Heritage Program include:
- protecting habitat within public natural areas and private nature
- completing extensive surveys of known and potential habitat of endangered
and threatened plants and animals, and
- developing management plans with public agencies and private developers
through state wide permitting and enforcement systems.
How You Can Help
- Voluntarily protect coastal dunes and shoreline habitat where this and
other special plants and animals of the Great Lakes live.
- Learn the differences between Dwarf Lake Iris and False Asphodel.
- Report your observations, including possible new locations of iris, by
contacting the Michigan Department of Natural Resources.
- Report destruction of this plant or the habitat in which it occurs by
calling the Report All Poaching (R.A.P.) Hotline at 1 800 292 7800.
- Become involved with a land conservation organization.
- Support the Nongame Wildlife Fund by purchasing a
wildlife habitat license
plate, or through a
Did You Know…?
This unique iris is Michigan's state wild flower.
"Lacustris" translates literally to mean "of lakes" and refers to where this
beautiful iris grows. Dwarf Lake Iris was first found on Mackinac Island in 1810
by Thomas Nuttall, a renowned naturalist and explorer. Nuttall reached Mackinac
Island after travelling from Detroit by canoe with French Canadian voyagers and
the surveyor for the Michigan Territory. At least 1/3 of the species that
Nuttall reported from the Great Lakes were new to science.
information was written by Elaine A Chittenden with assistance from the Natural
Heritage Program and Michigan Natural Features Inventory staff.