2016-07-21_REVISION - M1980002

• Permit No: M1980002
• IBM Index Class Name: Revision
• Doc Date: 7/21/2016
• Doc Name: Request for Technical Revision
• From: Connell Resources, Inc.
• To: DRMS
• Type & Sequence: TR5
• Email Name: PSH
• Email Name: WHE
• Media Type: D
• Archive: No

Rangeland -Pasture Recommendations
Diffuse knapweed Identification and
Management
Diffuse knapweed (Ceidaurea difficsa) is a non-native biennial forb that
reproduces solely by seed. A biennial is a plant that completes its Iifecycle within
two years. During the first year of growth, diffuse knapweed appears as a rosette
in spring or fall. During the second year in raid to late spring - the stem bolts,
flowers, sets seed, and the plant dies. Once the plant dries up, it breaks off at
ground level and becomes a tumbleweed allowing seeds to be dispersed over
long distances. A prolific seed producer, diffuse
4. knapweed can produce up to 18,000 seeds per plant.
Therefore, the key to managing this plant is to
t:
* x+€ prevent seed production.
Diffuse knapweed can grow 1 to 3 feet tall,
and is diffusely branched above ground. This gives
the plant a ball -shaped appearance and tumble-
weed mobility when broken off. Leaves are small,
and are reduced in size near the flowering heads.
Flowers are mostly white, sometimes purple, urn -
shaped, and are located on each branch tip. Bracts
that enclose the flowerheads are divided like teeth
of a comb, and are tipped with a definite slender
spine. Upon drying, the bracts become rough,
rendering them injurious to the touch.
You can expect to see flowers from July
through August. Seed set usually occurs
by mid-August.
Diffuse knapweed tends to invade
disturbed, overgrazed areas.
It may also be found on rangeland,
roadsides, riparian areas, and trails. It is a
tough competitor on dry sites and rapidly
invades and dominates disturbed areas.
Once established, diffuse knapweed
outcompetes and reduces the quantity of desirable native species such as
perennial grasses. As a result, biodiversity and land values are reduced, and soil
erosion is increased.
On the backside of this sheet are diffuse knapweed management
recommendations. If you have any questions, please contact the Weld County
Public Works Dept., Weed Division at [phone], ext. 3770. Please visit our
website www.weldweeds.org.
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Once established, diffuse knapweed
outcompetes and reduces the quantity of desirable native species such as
perennial grasses. As a result, biodiversity and land values are reduced, and soil
erosion is increased.
On the backside of this sheet are diffuse knapweed management
recommendations. If you have any questions, please contact the Weld County
Public Works Dept., Weed Division at [phone], ext. 3770. Please visit our
website www.weldweeds.org.