Transcript Urban Weed Management - Montana State University

Residential Weed
Management
Montana Pesticide Education Program
http://mtpesticides.org
What is considered a weed?
• Any plant growing where it is not
wanted.
• Obnoxious Weeds
– Toxic Weeds
– Invasive and Noxious weeds are the most
troublesome.
• Rapidly dominate the site
• Very difficult to control
Weeds are Indicators of Site
Conditions
• Salty Soils
– Shepherds Purse, Russian Thistle
• Acid soils – Very Acid Soils
– Horsetail – Hawkweed & Knapweed
• Badly drained soils
– Horsetail
• Deep shade
– Ground ivy, chickweed
Noxious Weeds in Montana
• Landowners are responsible for controlling the
spread noxious weeds on their property
• Cat 1 = established & widespread
• Cat 2 = recently introduced and rapidly spreading
• Cat 3 = Not yet detected or in few locations
Category 2
Category 1
Noxious Weeds in Montana
Category 3
Weed Management
Prevention is the most effective practice of all!
• Buy clean seed for wildflowers or
lawns; don’t plant weeds!
• Clean yard equipment before using it in
another area
• Get weeds along streams
under control
• Use mulch materials
or weed mats
• Pull weeds early –
before they go to seed!
Control Methods
Mechanical
• Mowing, hand pulling, burning, solarizing
Cultural
• Shading, site preparation, plant
appropriate competitive vegetation
Biological
• Parasites, predators, and pathogens;
typically a slow process – not for urban
Chemical
• Repeated application
• Plants must be growing
• USE ACCORDING TO LABEL
Weed Biology/Life Cycles
Exploit Weed Weaknesses
• Monocots: parallel leaf veins,
Grasses
growth points at/below soil level
–Grass family
•Cheatgrass, quackgrass
–Sedge family
•Nutsedge
–Lily family
•Wild onion, death camas
 Dicots:
net-like leaf veins, diverse
Broadleaf
growing points
–Composite family
•Dandelions, thistles, knapweed
–Mustard family
•Shepherd's purse, lambsquarter, whitetop
–Carrot family
•Hemlock
Many others
Stages of Weed Development
• 1. Seedling
– Tender, vulnerable
• 2. Vegetative
– Great uptake of
water and
nutrients
• 3. Seed production
– Reduced uptake,
energy directed to
flowers, fruit
• 4. Maturity
– Little uptake or
energy production
• Annual weeds: live one year
– Summer annuals: seed & die by winter.
• Pigweed, lambsquarter, black medic
– Winter annuals: germinate in late summer,
overwinter, produce seed, die the next
season.
• Chickweed, curly dock, cheatgrass,
black medic
Biennial weeds: broadleaf plants
with a 2-year life cycle
– vegetative growth first year (Rosette)
– mature, seed and die in second year
Houndstongue, mullein, burdock, bull thistle
• Perennial weeds: live 3 or more years
– most persistent
– difficult to control
– propagules
• rhizomes, stolons, bulbs, tubers
– wide range of dicots and monocots
Managing Landscape Weeds
• Maintain competition – grazing
management
• Prevent seed production
• Prevent seed germination
• Limit emerged weeds early
• Limit susceptible stages of mature
weeds.
Chemical designed to
control weeds. Plant, soil
and weather conditions
influence herbicidal
activity.
Herbicide
Characteristics
Contact
Systemic
Herbicide
Characteristics
Persistent
Non
Persistent
Herbicide
Characteristics
Selective
Non
Selective
Herbicide Characteristics
• Application in relation to plant
development
– Pre-plant
• Before crop is planted
– Pre-emergent
• Before weeds emerge
– Post emergent
• After weeds emerge
Herbicides and Plant
Characteristics
• Growing points
• Leaf shape and orientation
• Wax and cuticle
Herbicides and Plant
Characteristics
 Leaf
hairs
 Deactivation
 Life
cycle stage
Herbicide Effectiveness
100
80
60
% control
40
20
0
seedling
vegetative
flowering
mature
Climatic Factors
• Relative humidity
• Light
• Precipitation
• Temperature
Bull Thistle (Cirsium vulgare)
Biennial
2-5 feet tall
Flowers purple JulySeptember
Reproduces by seed
Seed can be viable for
10 years
Control:
hand pull
cut or mow before going to seed
herbicides? When?
Canada Thistle (Cirsium arvense)
Perennial
Flowers light pink-purple
Grows 1-4 feet tall
Has deep horizontal roots
Reproduces through
creeping roots, some seed
Control:
pull by hand (small plants)
apply herbicides; spot-spraying
young plants is very effective
Poison Hemlock (Conium maculatum)
Biennial
Grows to 10 feet tall
Tiny white flowers &
purple-mottled stems
All parts of plant are
highly poisonous (if
eaten)
Reproduces by seed
Control:
hand pull or dig* (small plants)
apply herbicides in early spring or late fall
*be sure to wear gloves & properly dispose of all plant
material
Purple Loosestrife (Lythrum salicaria)
Perennial
Flowers purple on
spikes
Stems are square; plant
can be 6-8 feet in height
Reproduces by seed
and roots
Control:
cut, dig, or hand pull (small
plants)
cut and remove the flowering
spikes to prevent new seedlings
apply herbicides when actively
growing at full to late flowering
Weed treatment in riparian areas
• Select the most
effective treatment
methods for the site
• If herbicides are used,
be sure the label
allows application
adjacent to or in the
water
• Consider wipe
application or hand
removal
Herbicides in a
Residential Setting
Animals & kids
Non-target vegetation
Concerns over chemical use
Movement of contaminated soil
and vegetation
Drift
Sensitive areas
Where is this water going?
Sprayers For
Urban/Residential Use
Up to 1 acre
> 1 acre
on
Skiddepending
Mount
tank size & GPA
Hose End
Spot Treatment < 1/10th acre
ATV & Lawn Tractor
Backpack
Hand Held
General Precautions
Prevent Drift
Calibrate Your Sprayer
Add the right amount
Use
Common
Sense
What To Use
1.30% Dicamba
3.05% 2,4-D
10.6% MCPP
8.0%
Triclopyr
Now what?
• Inventory the plants on
your property
• Identify invasive plants
and weeds
• Do you have a weed
problem? Why?
• What can you
change about the
way you manage
your property to
decrease the weed
population?
Then...
• Determine appropriate
controls and your plans for
the site and start working
• Monitor for invasive plants
• Plant native plants in your
yard after the weeds are
under control
• Share this information with
others