Download Weed Control in the Landscape

Weed Control in Homeowner
Ornamentals
Tim R. Murphy
The University of Georgia
Landscape
Ornamental Weed Control Options
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Hand-removal, hoeing
Mulches
Landscape fabrics
Herbicides
#1 Home Owner Question
What can I spray on *&^#@!?
weed to kill it and how much
do I need??
Mechanical Control
Fabric Mulches
Plastic or fabric thickness affects the degree of
weed suppression.
 Clear and colored plastics that allow light
penetration produce high temperatures in the
upper surface.
 This build up of heat, solarization, kills
germinating weed seeds.
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Landscape Fabrics
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Expensive
Limited commercial use
Very good option for homeowners
Use high quality, non-woven, fused fabric
Properly mulch
Organic Mulches
Straw, wood chips, pine straw, sawdust,
newsprint, and other organic materials.
 These mulches also shade and physically
hinder germinating seedlings
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Organic Mulches
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Coarse texture better than fine
Texture more important than type
2 to 4 inch depth
Renew as needed
Nothing is permanent!
Mulches
Advantages
Disadvantages
control most weeds
good use of “waste”
materials
Conserves water
expensive??
handling is often
a pain
Mechanical Control
Hand Pulling and Hoeing
 Still
used for weed control in high value
crops
 Best control with small weeds <4 inches
 Must understand how the weed develops
(annuals vs. perennials)
Hand Weed Control
Advantages
Disadvantages
keeps you in shape
environmentally friendly
controls most weeds
Inexpensive (if done
by self
repetition is a must
can stimulate germination
must be timely
Mechanical Control
Tillage
 Controls
many weeds that have emerged
 Incorporate
 Prepares
fertilizers, lime
seed or plant beds
Tillage Practices
Advantages
Disadvantages
control most weeds
quick and easy
expensive??
can’t get too close to
crop – root pruning
noise pollution
HERBICIDES
Ornamental – Homeowner Herbicides
• Annual grass control available
– Preemergence and postemergence
• Pre and Post broadleaf weed control is difficult
• Use post graminicides for perennial grass control
• Vines, woody plant control is exceeding difficult
Ornamental Preemergence Herbicides
• Primarily dinitroanilines
– Treflan, Surflan, Pendulum, Endurance, XL, Team
• Preen
• Preen-N-Green
• Snapshot - trifluralin + isoxaben
Ornamental Preemergence Herbicides
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Products labeled for various species
Irrigate-in if possible (1/2 inch) within 7 days
Do not apply to wet foliage
Match weeds to specific products
Use fall + spring applications
Rotate products if possible
Homeowner - Selective POST Grass
Control Herbicides
• Sethoxydim - Vantage, Hi-Yield Poast
– reseeding restriction: not listed
• Fluazifop -
Dexol Grassout
Greenlight Bermudagrass
Killer
Ortho Grass-B-Gon
- reseeding restriction: 2 months
Ornamentals – Post-Grass Control
• Use on any non-grass ornamental
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Trees, woodies, annuals, perennials
Includes liriope, hosta, iris, daylily
Don’t spray open blooms
No “nutgrass” control
Avoid applications on “scorchy-hot”, humid days
Integrated Weed Management
Integrating preventive, mechanical (mulches, fabrics),
cultural and chemical methods is usually the most
effective method of managing weeds in ornamentals.
Florida betony
Florida Betony - Stachys floridana
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Labitae (mint family)
“Rattlesnake weed”
perennial
reproduces primarily by tubers
opposite, serrated leaves
occurs in turf and ornamentals
Florida Betony Control
• Roundup, Finale
• Casoron applied in winter, very difficult to find,
can be ordered at Southern States, commercial
herbicide stores
• Use landscape fabric in ornamentals
Bamboo
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Phyllostachys aurea
Grass family
rhizomatous
rarely fruits
no wildlife value
full sun, partial shade
native to China
Bamboo Control
• No herbicide is labeled for the control of
bamboo.
Bamboo Control
• Roundup Pro, 2% v/v, apply to regrowth 3 to 6
feet tall, repeat, not on label
• Roundup Pro, 33% v/v, apply with gloved hand
to husk stage, repeat, not on label
• MSMA, 2% v/v, will “knock” leaves off, repeat
• Mechanical barrier, 30 inches deep
Phyllanthus spp. - Biology
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Summer annuals
Spurge family
Seeds require light
Tolerates full sun and moderate shade
Chamberbitter, niruri, gripeweed
Chamberbitter - Phyllanthus niruri
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Euphorbiaceae (spurge family)
niruri, gripeweed, leafflower
summer annual, reproduces by seed
alternate leaves, numerous leaflets
inconspicuous flowers
stalkless green, round fruit
no milky juice
Longstalked Phyllanthus
Longstalked Phyllanthus
(Phyllanthus tenellus)
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Euphorbiaceae (spurge family)
summer annual, reproduces by seed
alternate leaves, numerous leaflets
inconspicuous flowers
stalked green, round fruit
no milky juice
Phyllanthus spp. - Control
• Use mulch
• Apply early spring
Phyllanthus spp.
Preemergence Control
• Ronstar (not labeled for use in home
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landscapes)
Rout (OHII - slightly less effective)
Surflan + Gallery (Snapshot TG - less effective)
Prodiamine (Factor, Endurance, Barricade)
Gallery
Phyllanthus spp.
Postemergence Control
• Roundup Pro
• Finale
• Reward LS
Phyllanthus spp.
Ineffective Herbicides
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Basagran T/O
Image
MSMA
Pennant
Pendimethalin
Balan
Isoxaben Products - Homeowners
• PRE herbicide for control of annual
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broadleaf weeds
Primarily used in woody ornamentals
Gallery
Greenlight Portrait
Reseeding restrictions - 2 months
EPTC Products - Homeowners
• PRE control of annual grass and broadleaf
weeds
• Woody ornamentals, some flowers,
groundcovers
• Preen for Groundcovers
Homeowner - Nutsedge Herbicides
• Image – imazaquin
– reseeding restriction: 6 weeks
• Manage – halosulfuron
-reseeding restriction: 4 weeks
• Bentazon
– Basagran T/O, Hi-Yield Basagran
– reseeding restriction: 0 week
Sedge Herbicides -Ornamentals
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Basagran T/O - yellow, annual sedges
Manage - yellow, purple, annual sedges
Image - yellow, purple, annual sedges
Pennant - yellow, annual sedges
– Preemergence only
– No homeowner package available
Basagran T/0 - Ornamentals
• Directed spray around base of ornamentals
• Over-the-Top
– Hollies, ornamental cabbage, pachysandra
– Liriope, impatiens, marigold
– English ivy, petunia, ajuga
• “Safer”option for yellow nutsedge than Roundup
Pro
Manage - Ornamentals
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Post-directed around woody ornamentals
New-transplants- wait 3 months
Do not use in annuals or herbaceous perennials
May be applied 4 weeks in advance of
transplanting woody ornamentals
Image - Ornamentals
• Over-the-top
– Junipers, Burford hollies, Helleri holly, Indian hawthorne,
– Liriope, mondograss, hostas, Red tip photinia
– Pachysandra, Asiatic & Confederate jasmine
• Do not apply over root zone of non-listed ornamentals
• Azalea, ligustrum, viburnum, pieris, abelia are severely
injured by Image
Dodder
Dodder - Cuscuta spp.
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Convolvulaceae (morningglory family)
rootless, leafless parasitic annuals
“yellow spaghetti”
prolific seed producer
germinates early spring
8 species known in Georgia
wide host range on broadleaf plants
Dodder Control - Ornamentals
• Fumigate - Basamid
• Casoron, Norosac - woody ornamentals, may be
difficult to find
• Dacthal - dropped by manufacturer
• Kerb - woody ornamentals, Restricted Use
Herbicide
• Roundup, Finale