weeds in the landscape. weed life cycles annuals: begin season as seed and finish life cycle in one...
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Weeds Weeds in the in the LandscapeLandscape
WEED LIFE CYCLESWEED LIFE CYCLES
AnnualsAnnuals: begin season as seed and : begin season as seed and finish life cycle in one yearfinish life cycle in one year
Produce massive amounts of seedProduce massive amounts of seed
Summer AnnualSummer Annual Germinate in spring and die in winterGerminate in spring and die in winter
WEED LIFE CYCLESWEED LIFE CYCLES
AnnualsAnnuals: begin season as seed and : begin season as seed and finish life cycle in one yearfinish life cycle in one year– Produce massive amounts of seedProduce massive amounts of seed
WinterWinter AnnualAnnual Germinate in fall, die in summerGerminate in fall, die in summer
WEED LIFE CYCLESWEED LIFE CYCLES
BiennialBiennial: 2 growing seasons: 2 growing seasons First seasonFirst season—vegetative parts —vegetative parts Second seasonSecond season – flowers and seeds – flowers and seeds
WEED LIFE CYCLESWEED LIFE CYCLES
PerennialsPerennials: live 3 years or more: live 3 years or more Die back to ground in winter and Die back to ground in winter and
regrow from roots, tubers, rhizomes, regrow from roots, tubers, rhizomes, or stolonsor stolons
Limited seedLimited seed
WEED LIFE CYCLESWEED LIFE CYCLES
PerennialsPerennials Difficult to control because of Difficult to control because of
underground portionsunderground portions
WEED GROWTH HABITWEED GROWTH HABIT
GrassyGrassy: true grasses: true grasses Perennial or annualPerennial or annual
WEED GROWTH HABITWEED GROWTH HABIT
BroadleafBroadleaf: (mostly) wide leaves: (mostly) wide leaves
WEED GROWTH HABITWEED GROWTH HABIT
Non-grassNon-grass Sedge, rushes, onion and garlicSedge, rushes, onion and garlic
DESIGN TO AVOID WEEDSDESIGN TO AVOID WEEDS
Plant selectionPlant selection Less affected by weed competitionLess affected by weed competition
DESIGN TO AVOID WEEDSDESIGN TO AVOID WEEDS
EdgingEdging Borders that restrict invasionBorders that restrict invasion
DESIGN TO AVOID WEEDSDESIGN TO AVOID WEEDS
Drip irrigationDrip irrigation Avoid providing water to weedsAvoid providing water to weeds
DESIGN TO AVOID WEEDSDESIGN TO AVOID WEEDS
DESIGN TO AVOID WEEDSDESIGN TO AVOID WEEDS
DESIGN TO AVOID WEEDSDESIGN TO AVOID WEEDS
Competitive plantsCompetitive plants Dense canopies shade out bare Dense canopies shade out bare
groundground
SITE PREPARATIONSITE PREPARATION
Eliminate established weedsEliminate established weeds
SITE PREPARATIONSITE PREPARATION
CultivationCultivation Rototilling Rototilling
SITE PREPARATIONSITE PREPARATION
SolarizationSolarization Tarping soil to retain sun’s heat and Tarping soil to retain sun’s heat and
destroy weeds seedsdestroy weeds seeds Can also reduce disease and Can also reduce disease and
nematode nematode
SITE PREPARATIONSITE PREPARATION
Solarization Solarization Cover with clear plasticCover with clear plastic Seal edges for greenhouse effectSeal edges for greenhouse effect Cover 4 to 6 weeksCover 4 to 6 weeks Avoid bringing up soil deeper than Avoid bringing up soil deeper than
3”3”
SITE PREPARATIONSITE PREPARATION
Weed fabricWeed fabric Breathable fabricBreathable fabric No plasticNo plastic
Pittosporum (4 years)Pittosporum (4 years)Mulch onlyMulch only
Mulch + 1 application Mulch + 1 application of preemergent of preemergent herbicideherbicide
Mulch + weed fabricMulch + weed fabric
SITE PREPARATIONSITE PREPARATION
MulchMulch Prevention of annual weed Prevention of annual weed
germinationgermination Excludes lightExcludes light Moisture retentionMoisture retention Soil temperature stabilizerSoil temperature stabilizer Enrich soilEnrich soil
SITE PREPARATIONSITE PREPARATION
Organic mulchOrganic mulch BarkBark Shredded mulchShredded mulch Pine strawPine straw
Inorganic mulchInorganic mulch StoneStone Recycled rubberRecycled rubber Synthetic pine strawSynthetic pine straw
SITE PREPARATIONSITE PREPARATION
SITE PREPARATIONSITE PREPARATION
Organic mulchOrganic mulch Maintain 2 to 4” deepMaintain 2 to 4” deep Keep away from base of plants about Keep away from base of plants about
1’ from trunk1’ from trunk
CONTROL ESTABLISHED CONTROL ESTABLISHED WEEDSWEEDS
Preventing seed introductionPreventing seed introduction Wash equipmentWash equipment Avoid contaminated stockAvoid contaminated stock
CONTROL ESTABLISHED CONTROL ESTABLISHED WEEDSWEEDS
CultivationCultivation – avoid under trees – avoid under trees Disturbs rootsDisturbs roots Won’t effect vegetative weeds Won’t effect vegetative weeds
– dollarweeddollarweed
CONTROL ESTABLISHED CONTROL ESTABLISHED WEEDSWEEDS
String trimString trim Avoid hitting trunkAvoid hitting trunk
CONTROL ESTABLISHED CONTROL ESTABLISHED WEEDSWEEDS
String trimString trim Mulch to avoid damage to trunkMulch to avoid damage to trunk Tree guardTree guard
CONTROL ESTABLISHED CONTROL ESTABLISHED WEEDSWEEDS
FlamingFlaming Torch base of plant, disrupt cellsTorch base of plant, disrupt cells Primarily annualsPrimarily annuals
CONTROL ESTABLISHED CONTROL ESTABLISHED WEEDSWEEDS
HerbicidesHerbicides FumigantsFumigants kill everything in soil kill everything in soil
CONTROL ESTABLISHED CONTROL ESTABLISHED WEEDSWEEDS
HerbicidesHerbicides
Pre-emergentPre-emergent: kill germinating weeds : kill germinating weeds for several weeksfor several weeks
Must be applied before germinationMust be applied before germination
EdgingEdging Borders that restrict invasionBorders that restrict invasion
CONTROL ESTABLISHED CONTROL ESTABLISHED WEEDSWEEDS
HerbicidesHerbicides
Post-emergentPost-emergent: kill weeds already : kill weeds already germinatedgerminated
Most effective on young, vigorously Most effective on young, vigorously growing weedsgrowing weeds
CONTROL ESTABLISHED CONTROL ESTABLISHED WEEDSWEEDS
Postemergent HerbicidesPostemergent Herbicides
Contact versus SystemicContact versus Systemic ContactContact: kills only green parts that : kills only green parts that
are sprayedare sprayed Quick killQuick kill No underground killNo underground kill
2 hours2 hours
24 hours24 hours
CONTROL ESTABLISHED CONTROL ESTABLISHED WEEDSWEEDS
Postemergent HerbicidesPostemergent HerbicidesContact versus SystemicContact versus Systemic SystemicSystemic: translocated to roots and : translocated to roots and
growing tipsgrowing tips Good on perennial weedsGood on perennial weeds During vigorous growthDuring vigorous growth
– Round-up and NRound-up and N May take a few days to a few weeksMay take a few days to a few weeks
CONTROL ESTABLISHED CONTROL ESTABLISHED WEEDSWEEDS
Postemergent HerbicidesPostemergent Herbicides
Selective versus Non-selectiveSelective versus Non-selective SelectiveSelective: only certain types of : only certain types of
plants affectedplants affected– Broadleaf onlyBroadleaf only– Grassy onlyGrassy only
CONTROL ESTABLISHED CONTROL ESTABLISHED WEEDSWEEDS
Postemergent HerbicidesPostemergent Herbicides
Selective versus Non-selectiveSelective versus Non-selective Non-selectiveNon-selective: kills everything that : kills everything that
is sprayed is sprayed
