yellow flag iris
Scientific Name: Iris pseudacorus
(yellow flag iris) (5)
Family Name: Iridaceae
is 4-6 ft. in height, and are spaced from about 36-48 in. apart.
The plant is the only yellow iris in the United States.
The yellow flag iris has a robust stalk, and the plant has a
long blooming season. (2, 5)
The roots of the yellow flag iris are 10-30 cm
The yellow flag iris is a tall plant
with long, dark green, flattened, sword like leaves. The
leaves can grow up to 2.5 cm wide. The leaves also arise
usually longer than the stem. (3, 5)
The size of the flower is 3-4 inches across,
and is yellow. The flower is 8-10 cm in diameter. It
has 3 sepals that are backward curving and non bearded. The flower
time is from June-August. (3, 5)
The fruit of this weed is oblong and
capsule-like and also usually 2" long. (5)
Methods of Reproduction/Spread:
The plant is slowly
spread and easily contained. It is spread by the wind and water.
The wind catches the seed and blows it into the water and the
water carries it downstream to its new home. (5)
Life Styles/Habits/Life Duration:
Environments Favorable to
Yellow-flag-iris will continue to
spread as long as it is being sold in stores and nurseries, and
also it will move down stream just by the seeds and plant parts.
Yellow-flag-iris is a fast growing and
fast spreading weed. It creates thickets in water just like
Native Range/probable entry into N. America:
native to Europe, British Isles, North Africa and the
Mediterranean region; unfortunately yellow flag iris is sold over
the internet on gardening web sites. Yellow-flag iris
entered the U.S. from Canada as an ornmental plant in the early
Rare, North Western Montana.
Methods of Control:
One of the most useful ways to
control this plant is to use chopping machines that destroy the
bulbs/roots. There is no biocontrol for this species at this
time. Animals seem to eat yellow flag iris with their hay
and other foods out in the wild. (6)
How to Prevent the Spread:
No data available.
: Yellow flag iris lives along stream beds,
near ponds, and in marshes. (5)
1. "yellow flag iris." Perennials on parade. 3/16/04. Kurt Weiss
Greenhouse, Inc.. 3/16/04
2. "yellow flag iris." Non-Native Invasive Aquatic Plants in
the United States. 3/16/04. Center for Aquatic and Invasive
3. . "Skye Flora." Yellow Flag. April 7, 2003. Photo @ Carl
4. . "Yellow Iris (Yellow Flag)." Connecticut Botanical Society.
Feb. 15, 2003. Connecticut Wildflowers. 3/11/04
5. "Wildflowers." enature.com. . National Wildlife Federation.
6. University of Florida Aquatic Weed Management Guide, Vandiver
7. Cody WJ. 1961. Iris pseudacorus L. escaped from cultivation in
Canada. Canadian Field Nat., 75: 139-142.
8. No author found.
9. Falinska K. 1986. Demography of Iris pseudacorus L. populations
in abandoned meadows. Ekol. Polska 34(4):583-613,
Zac & Layne
03/04. Updated By:
Ben Foster 3/1/07.
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