McGregor MN - Big Sandy Lake Association

During an aquatic plant workshop in the summer of 2008 two Prohibited
species were found on Big Sandy Lake, Flowering Rush (Butomus
umbellatus) and Purple Loosestrife (Lythrum salicaria). Below is the
description for Flowering Rush.

Appearance: Perennial aquatic herbaceous plant. It grows 1-4' high on an
erect stem along shores in shallow water. In deeper water it grows
submerged without producing flowers.

Flowering rush is very difficult to identify when not in flower. It closely
resembles many native shoreland plants, such as the common bulrush.

Leaves: Leaves are sword-shaped, triangular in cross section. Flowers:
Pink flowers are arranged in umbels (umbrella-shaped).

Seeds: Populations in the eastern U.S. produce seeds. Only one
Minnesota population (Forest Lake) produces viable seeds.

Roots: Reproduces by vegetative spread from its rootstock in form of
bulb-lets. Both seeds and bulb-lets are dispersed by water current.

Ecological Threat: Flowering rush is actively expanding. It has spread
from a limited area around the Great Lakes and the St. Lawrence River to
sporadically appear in the northern U.S. and southern Canada. It competes
with native shoreland vegetation.

It is a Eurasian plant that is sold commercially for use in garden pools. It is
now illegal to buy, sell or possess the plant. There is documentation from a
site in Idaho, between 1956 and 1973, where flowering rush appeared to be
out-competing willows and cattails.

Flowering rush is on the DNR Prohibited exotic species list in Minnesota.
All the proper authorities have been notified and will follow up with
updates on the web site.