[Partners-IMCWMA] article on mowing and weeds

[Mendocino County Farm Bureau]

Hi Tara: When completed, could you forward the final to me? I would love
to have the article in Mendocino Country Life too.
Thanks Carre

-----Original Message-----
From: partners-bounces at imcwma.org [mailto:partners-bounces at imcwma.org]
On Behalf Of Tara Athan
Sent: Monday, March 26, 2007 6:58 PM
To: IMCWMA partners
Subject: [Partners-IMCWMA] article on mowing and weeds

IMCWMA Partners- I have put together an article on mowing and weeds for 
the brochure that the fire-safe council will be putting out soon.
If you have time, please look over the following for accuracy.

Thanks, Tara

Weed control, wildfire fuel reduction and mowing: Putting it all
together

1. Whether to mow at all
Not every wildland location needs to be mowed for wildfire hazard 
reduction. Shady areas may not produce enough dry vegetation to be a
hazard.  Wet areas near streams and springs may stay sufficiently moist 
and green to act as a fuel break. Grasslands dominated by
perennial grasses and late-blooming wildflowers may maintain green 
vegetation well into late summer. Mowing may be advisable as part
of an integrated weed management strategy, even if wildfire is not an 
issue. However, you can save time, money, use less gas,
encourage desirable vegetation and reduce the risk of accidental 
ignition by only mowing when it is needed.

2. Timing your mowing: when to start, how often, when to stop
Now suppose you have made the decision to mow a particular area.
What is the right time to mow?
The answer is: it depends.
It depends on the reason you are mowing, the vegetation present, the 
weather and the soil moisture.
Whether you are mowing for fuel reduction or to modify the plant 
composition of your fields, it is important to understand that mowing
can favor some species over others, depending on when and how it is
done.

Mowing early can be damaging to equipment and desirable vegetation if 
the soil is too damp.
Wait at least until the soil is dry enough to support the mower.
This time can vary from one year to the next and from one location to 
the next.
It is important to know your property and pay attention to its condition

throughout the year.

Mowing too early and often can favor certain late blooming weeds, such 
as yellow starthistle.
Mowing too late can disperse the seeds of non-native annual grasses, 
such as slender wild oat.
For Harding grass suppression, mow when the plants are still green but 
seasonal moisture is almost exhausted.


To encourage desirable annuals (plants that die yearly and grow back 
only from seed) such as valley lupine or common madia, mow only
before the plant has bolted (produced a flower stalk) or after the 
flowers have gone to seed and the seed is mature.


To discourage an annual weed, mow when it is in flower (grass has 
flowers too, even though they are not very showy). You can also mow
before seed heads are fully matured - gather and sterilize (burn or 
thoroughly compost) clippings with seed heads still attached.   In
particular, for yellow starthistle suppression, mow for the first time 
when the first starthistle flowers appear and then again about
6 weeks later to catch any flowers that grow back. This second mowing 
will usually occur in July, and so must be conducted carefully
to avoid starting a wildfire. 

Perennials (plants that stay green all year or grow back from the roots 
after a dormant period) such as California oatgrass (Danthonia
californica) and the many beautiful native irises and lilies can be 
encouraged by suppressing the competing annuals that grow earlier
and faster.  There is an added advantage to perennial grasses - they 
reduce wildfire hazard because they stay green longer.


3. Height of mowing
Setting the mower blade low is not usually recommended in wildland 
situations because of:
 >increased risk of hitting rocks and creating sparks that could start a

fire.
 >increased damage to perennials when they are cut low.
 >greater soil disturbance when the blade bites into the ground in 
uneven terrain, creating habitat for invading weeds.
 >greater risk of damage to the mower blade from contact with soil, 
rocks and tree roots.
A blade height of at least 4 inches will reduce these damages in most 
situations.

Conclusion
It can be a challenge to simultaneously balance the requirements of 
wildfire fuel reduction and weed control.
Developing a long-term management plan, on your own or with the 
assistance of professionals,
can be of great assistance in meeting all of your land management goals.

For further information, see imcwma.org and cal-ipc.org

-- 
Tara Athan
Coordinator, Inland Mendocino Cooperative Weed Management Area
coord at imcwma.org
707-485-1198
PO Box 415
Redwood Valley, CA 95470


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