Download - Proper Mulching Techniques
Proper Mulching TechniquesMulching is one of the most beneficial practices a homeowner can use for better tree health.
Mulches are materials placed over the soil surface to maintain moisture and improve soil conditions. Mulching is one of the most beneficial acts a homeowner can do for the health of a tree. However, improper mulching materials and practices may have little, or even negative, impact on the trees in your landscape.
Benefits of Proper Mulching• Helpsreducesoilmoisturelossthroughevaporation• Helpscontrolweedgerminationandgrowth• Insulatessoil,protectingrootsfromextremesummerandwintertemperatures• Canimprovesoilbiology,aeration,structure(aggregationofsoilparticles),anddrainageovertime• Canimprovesoilfertilityascertainmulchtypesdecompose• Inhibitscertainplantdiseases• Reducesthelikelihoodoftreedamagefrom“weedwhackers”orthedreaded“lawnmowerblight”• Givesplantingbedsauniform,well-cared-forlook
Treesgrowinginanaturalforestenvironmenthavetheirrootsanchoredinarich,well-aeratedsoilfullofessentialnutrientsandsoilmi-croorganisms.Thesoilisblanketedbyleaves,organicmaterials,andlivingorganismsthatreplenishandrecyclenutrients.Thisenviron-mentisoptimalforrootgrowthandmineraluptake.Urbanlandscapesandnewdevelopments,however,aretypicallyharsherenviron-mentswithpoorqualitysoils,reducedorganicmatter,andlargefluctuationsinsoiltemperatureandmoisture.Applyinga2-to4-inch(5-to10-cm)layeroforganicmulchcanmimicamorenaturalenvironmentandimproveplanthealth.
Types of MulchMulchesareavailableinmanyforms.Thetwomajortypesofmulchareinorganicandorganic.Inorganicmulchesincludevarioustypesofstone,lavarock,pulverizedrubber,geotextilefabrics,andothermaterials.Inorganicmulchesdonotdecomposeanddonotneedtobereplenishedoften.Ontheotherhand,theydonotimprovesoilstructure, addorganicmaterials,orprovidenutrients.Forthesereasons,mosthorticulturistsandarborists prefer organic mulches.
Organicmulchesincludewoodchips,pineneedles,hardwoodandsoftwoodbark, cocoahulls,leaves,compostmixes,andavarietyofotherproductsusuallyderivedfromplants.Organicmulchesdecomposeinthelandscapeatdifferentratesdependingonthematerial,climate,andsoilmicroorganismspresent.Thosethatdecomposefastermustbereplenishedmoreoften.Becausethedecompositionprocessimprovessoilqualityandfertility,manyarboristsandotherlandscapeprofessionalsconsiderthatcharacteristicapositiveone,despitetheaddedmaintenance.
Not Too Much!Asbeneficialasmulchis,toomuchcanbeharmful.Thegenerallyrecommendedmulchingdepthis2to4inches(5to10cm).Un-fortunately,manylandscapesarefallingvictimtoaplagueofovermulching.“Mulchvolcanoes”areexcessivepilesofmulchmaterialsappliedaroundthebaseoftrees.Whileorganicmulchesmustbereplenishedovertime,buildupcanoccurifreapplicationoutpacesdecompositionorifnewmaterialisaddedsimplytorefreshcolor.Deepmulchcanbeeffectiveinsuppressingweedsandreducingmain-tenance,butitoftencausesadditionalproblems.
Problems Associated with Improper Mulching• Onwetsoils,deepmulchcanleadtoexcessmoistureintherootzone,whichcanstresstheplantandcauserootrot.
• Pilingmulchagainstthetrunkorstemsofplantscanstressstemtissuesandmayleadtothedevelopmentofinsectanddiseaseproblemsorstemgirdlingroots.
www.isa-arbor.com•www.treesaregood.org
ThisbrochureisoneinaseriespublishedbytheInternationalSocietyofArboricultureaspartofitsConsumerInformationProgram.Youmayhaveadditionalinterestinthefollowingtitlescurrentlyintheseries:
AvoidingTreeandUtilityConflictsAvoidingTreeDamageDuring ConstructionBenefitsofTreesBuyingHigh-QualityTreesInsectandDiseaseProblems
MatureTreeCareNewTreePlantingPlantHealthCareProperMulchingTechniquesPalms
PruningMatureTreesPruningYoungTreesRecognizingTreeRiskTreatmentofTreesDamaged byConstructionTreeSelectionandPlacement
TreesandTurfTree Values WhyHireanArboristWhyToppingHurtsTrees
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• Somemulches,especiallythosecontainingfreshgrassclippings,canaffectsoilpHandmayeventuallyleadtonutrientdeficienciesortoxicbuildups.
• Mulchpiledhighagainstthetrunksofyoungtreesmaycreatehabitatsforrodentsthatchewthebarkandcangirdlethetrees.
• Thickblanketsoffinemulchcanbecomemattedandmayreducethepenetrationofwaterandair.
• Anaerobic“sour”mulchmaygiveoffpungentodors,andthealcoholsandorganicacidsthatbuildupmaybetoxictoyoungplants.
Proper Mulching Thechoiceofmulchandthemethodofapplicationcanbeimportanttothehealthoflandscapeplants.Thefollowingaresomeguidelinestousewhenapplyingmulch:
• Determinewhethersoildrainageisadequateandifthereareplantsthatmaybeaffectedbythechoiceofmulch.Mostcommonlyavailablemulchesworkwellinmostlandscapes.Someplantsmaybenefitfromtheuseofslightlyacidifyingmulch,suchaspinebark.
• Forwell-drainedsites,applya2-to4-inch(5-to10-cm)layerofmulch(lessifpoorlydrained).Coarsemulchescanbeappliedslightlydeeperwithoutharm.Placemulchouttotheedgeofatree’scrownorbeyond.Remember,ifatreehadasayinthematter,itsentirerootsystem(whichusuallyextendswellbeyondthedripline)wouldbemulched.
• Ifmulchisalreadypresent,checkthedepth.Ifsufficientmulchispresent,breakupanymattedlayersandrefreshtheappearancewitharake.Somelandscapemaintenancecompaniesspraymulchwithawater-soluble,vegetable-baseddyetoaddcolortofadedmaterial.
• Ifmulchispiledagainstthestemsortreetrunks,pullitbackseveralinches/centimeterssothatthebaseofthetrunkisexposed.Compostedwoodchipscanmakegoodmulch,espe-ciallywhentheyincludesomebarkandleaves.Freshwoodchipsalsomaybeusedaroundestablishedtreesandshrubs.Avoidusingfine,non-compostedwoodchips,assoilnitrogenmaybetakenupbytherootsasthewoodchipsdecompose.
