weeds in the landscape. weed life cycles annuals: begin season as seed and finish life cycle in one...

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