Neal and Carrawan 2004 NC State Univ Weeds n What is a weed? –A weed is a plant out of place.

Neal and Carrawan 2004 NC State Univ

WeedsWeedsWhat is a weed?

–A weed is a plant out of place


What Do Weeds Do?What Do Weeds Do?Compete with crops for resources

Interfere with crop quality and quantity

Reduce aesthetics of landscapeAffect function of turfgrassDisplace native flora


What Do Weeds Do?What Do Weeds Do?Cause allergiesHarm peopleHarbor insects and plant pathogens

Ragweed pollen causes hay fever


Weeds -- How Did They Get There?Weeds -- How Did They Get There?

Every shovel full of soil contains thousands of weed seeds -- waiting for an opportunity

Often we just provide the weeds with the opportunity and environment to flourish


Weed Seed Are Spread By:Weed Seed Are Spread By:

WindPeopleRain runoffBirds and other animals

Garden cultivation

Mowing Topsoil or

compost addition

Purchased plants


Invaders - weed dispersalInvaders - weed dispersalWind Surface waterBirds & animalsActivities of man

–site prep, cultivation, planting


How we introduce and move weeds

How we introduce and move weeds

–top soil–organic amendments–equipment–plants


Crabgrass

Kudzu

Multiflora rose

And, sometimes we intentionally introduce weeds

And, sometimes we intentionally introduce weeds


Bamboo

Water hyacinth

Japanese knotweed

More Plants (weeds) Intentionally Introduced More Plants (weeds) Intentionally Introduced


The First Step in Weed Management is Identification!

Weed Identification – Its More Than Knowing a Name!

The First Step in Weed Management is Identification!

Weed Identification – Its More Than Knowing a Name!


Why is it Important to Identify Weeds?Why is it Important to Identify Weeds?So you know

–when it germinates,–how it spreads,

And, so you can determine the most appropriate control measure(s) -- herbicides, cultivation, mulches, etc.


How do you correctly identify a weed?How do you correctly identify a weed? Compare to a photo

–Remember weeds can appear different due to site conditions

–Easiest to do when plant is flowering

Keys to Identification Send a sample to the local

Cooperative Extension office


Identification ResourcesIdentification ResourcesFor Piedmont and Coastal Plains

–Identifying Seedling and Mature Weeds in the Southeastern US

–Weeds of Southern TurfgrassMountains

–Weeds of the Northeast–Weeds of Southern Turfgrass


How to order:How to order:

Identifying Seedling and Mature Weeds in the Southeastern US (AG-208) – Publications Office, Box 7603 NCSU, Raleigh, NC 27695-7603 $10.00


How to order:How to order: Weeds of Southern

Turfgrass– Publication Distributions

Center IFAS Building 664 P. O. Box 110011 University of Florida Gainesville, FL 32611 (352-392-1764) $8.00 +

$3.00 shipping


How to order:How to order:

Weeds of the Northeast –Cornell University Press P. O. Box 6525 Ithaca, NY 14851-6525 607-277-2211 $29.95 plus $5 shipping


Some Web-Based Weed ID ResourcesSome Web-Based Weed ID Resources

www.ces.ncsu.edu/depts/hort/weeds www.ppws.vt.edu/weedindex.htm www.rce.rutgers.edu/weeds/ axp.ipm.ucdavis.edu/PMG/

weeds_common.html www.psu.missouri.edu/fishel/ www.ppws.vt.edu/newss/weedid.htm www.griffin.peachnet.edu/cssci/TURF/

turf.htm


How to send a sample for IDHow to send a sample for ID

Fresh samples: moisten sample; wrap in DRY paper towel; put in a zip-lock bag and mail on Monday or Tuesday to the appropriate specialist


How to send a sample for IDHow to send a sample for ID

If you cannot send it right away (or if you get the sample on Thursday or Friday: Lay flat on between newspaper; press.

Mail the dried, pressed sample to the appropriate specialist


Use the Sample Submission FormUse the Sample Submission Form

http://intra.ces.ncsu.edu/depts/cs/weedforms/2weedide.pdf or

http://www.cropsci.ncsu.edu/turffiles/weedid/weedid.htm

http://www.cropsci.ncsu.edu/aquaticweeds/weed_id/aquatic.htm


Classification of WeedsClassification of Weeds


Weed ClassificationWeed Classification

Ways weeds are classified–Lifecycle–Seed leaves–Growth habit–Susceptibility to herbicides


LifecyclesLifecycles

AnnualBiennialPerennial


Life cycle of an annual weed

SeedSeedling

Plant flowers

Plant setsseed

Plant dies


Life cycle of a winter annual weed

SeedSeedling

Plant flowers

Plant setsseed

Plant dies

FallSummer


Common winter annual weeds

Common winter annual weeds


Life cycle of a summer annual weed

SeedSeedling

Plant flowers

Plant setsseed

Plant dies

SpringFall


Common Summer Annual WeedsCommon Summer Annual Weeds

J. N

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J. N

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J. D

err

J. N

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Life cycle of a biennial weed

SeedSeedling

Plant flowers

Plant setsseed

Plant dies

Over-winters as

a rosette

First Season

Second Season


Common BiennialsCommon Biennials

Bull Thistle Queens Ann’s LaceMullein

J. D

iTom

aso

R. U

va

J. N

eal


Life cycle of a perennial weed

Seed Seedling

PlantFlowers

PlantOver-winters

Plant setsSeed

Roots/ rhizomesspread

New plant


Some common perennial weedsSome common perennial weeds

J. N

eal

J. N

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J. N

eal

R. U

va

R. U

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Perennial Weeds Reproduce By:Perennial Weeds Reproduce By:

Rhizomes

Tubers

Stolons

Bulbs

Seeds


Types of Perennial Weeds Types of Perennial Weeds Simple perennials Creeping perennials

–Rhizomes–Stolons –Creeping roots that produce shoots

Tuberous perennialsBulbous perennials


Simple PerennialsSimple Perennials

Spread by seedTap root or hardy fibrous root system

Examples: dandelion, plantain, dogfennel, pokeweed

Tap root


Creeping PerennialsCreeping Perennials

Reproduce and spread by – Underground stems (rhizomes)– Above-ground stems (stolons)– Creeping fleshy roots that

produce new shoots Many also reproduce by

seeds or other means.

Stolon

Rhizome


Tuberous PerennialsTuberous Perennials

Tubers are swollen, modified stems that are often resilient to controls, spread by cultivation, and may persist in the soil for years.

Tubers form on rhizomes

Tubers

J . N

e al


Bulbous PerennialsBulbous Perennials

Persist through the dormant season as a bulb

Wild garlic and wild onion produce bulblets, aerial bulblets, and seeds

R. U

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Weeds Are Also Classified By:Weeds Are Also Classified By:Cotyledons (Seed leaves)

Monocot (one seed leaf)

Dicot (two seed leaves)


MonocotsMonocots

One seed leaf when plant emerges

Long narrow leaves

Parallel veins


Monocots -- ExamplesMonocots -- Examples

GrassesOnionsGarlic

SedgesRushesLiliesDayflower


GrassesGrassesRounded or flattened stems and nodes

Have fibrous root systemsSome have fibrous roots, rhizomes or stolons for reproduction

Growing point is below surface


Grasses are identified by:

seedhead

blade

ligule

auricles

collar

bud leaf

rhizome

stolon

midrib

sheath

crown


Vernation or Leaf BudVernation or Leaf Bud

Rolled in the bud Folded in the bud


Absent Membranous Hairy

The

Sco

tts

Co.

The

Sco

tts

Co.

The

Sco

tts

Co.

LigulesLigules


LigulesLigulesAbsent Membranous Hairy


Absent Present Clasping

The

Sco

tts

Co.

The

Sco

tts

Co.

The

Sco

tts

Co.

AuricleAuricle


Branched spikePanicle Spike

SeedheadsSeedheads

The

Sco

tts C

o.

The

Sco

tts C

o.

The

Sco

tts C

o.


Branched spikePanicle Spike

SeedheadsSeedheads


Grass-Like WeedsGrass-Like Weeds Sedges: Sedges have triangular

“stems”. Grasses have flat or rounded “stems”.– Annual and perennial species– Most common and difficult to control

are yellow and purple nutsedge Wild Garlic and wild onion: hollow

leaves have a pungent onion-like or garlic-like aroma– Wild garlic is the most common


Yellow and Purple Nutsedges (Cyperus spp.)

Yellow and Purple Nutsedges (Cyperus spp.)

Grass-like, but “Sedges have edges” – triangular “stems”

Leaves emerge 3-ranked

Spread by rhizomes and over-winter as tubers

Tubers often introduced in top soil

A. S

enes

acJ.

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Yellow Nutsedge (Cyperus esculentus)

Yellow Nutsedge (Cyperus esculentus) Perennial with

rhizomes and tubers Emerge in late

spring; die in the fall “Daughter” plants

and tubers formed at tips of rhizomes

One plant can form as many as 6000 tubers

R. U

vaJ.

Nea

l


PurpleNutsedge (Cyperus rotundus)

PurpleNutsedge (Cyperus rotundus) Rhizomatous and

tuberous perennial Emerge in mid-

spring; die in the fall

Forms tubers within 6 weeks of emergence

Very hard to control The “world’s worst

weed”

J. N

eal

Forms tubers in “chains”

J. N

eal


Yellow vs. Purple – Leaf tipsYellow vs. Purple – Leaf tips

Yellow nutsedge leaf tips taper to a long, narrow point

Purple nutsedge leaf tips are pointed but not tapered

Yellow PurpleJ.

Nea

l


Yellow vs. Purple -- FlowersYellow vs. Purple -- Flowers

Yellow fading to tan

Yellow Nutsedge

J. D

err

Purple or reddish brown turning black

Purple Nutsedge

J. N

eal


Wild Garlic (Allium vineale)

J. N

eal

R. U

va

Aerial bulblets

Bulbous perennial

Strong scent Reproduces

by bulblets, rarely by seed

Emerges in the winter and dies back in late spring or early summer


Dicots or Broadleaf weedsDicots or Broadleaf weeds

Two seed leaves (cotyledons)

Leaves have netted veinsLargest group of weedsOften with bright showy flowers

Exposed growing points


How to ID DicotsHow to ID Dicots

FlowersUnique CharacteristicsGrowth HabitLeaf Orientation, Shape, Etc.


Unique CharacteristicsUnique Characteristics

Look for:–Thorns or spines–Square or winged stems–Compound leaves–Whorled leaves–Milky sap

R. U

va


Growth HabitsGrowth HabitsJ.

Nea

l

Upright Spreading

J. N

eal


Leaf OrientationLeaf Orientation

Opposite

Alternate

Whorled

Rosette


Simple Verses Compound LeavesSimple Verses Compound Leaves

R. U

va

Simple

Pinnate Palmate

Compound

J. D

err


Other Ways to Identify Cont.Other Ways to Identify Cont.Leaf shapeLeaf margin

–Toothed,entire,lobed, or deeply cut

Petiole lengthHair on leaves or other parts


Leaf Shapes, tips & basesLeaf Shapes, tips & bases


Leaf MarginsLeaf MarginsR

. Uva

J. D

itom

aso

Entire

Deeply lobed

Shallow lobes or toothed


Hairs – present or absent, & where?Hairs – present or absent, & where?

J. D

iTom

aso

Mouseear chickweed -- Hairs on stem & leaves

Common chickweed -- Hairs absent

J. N

eal


Tell Me What You See?Tell Me What You See?



RosetteBroad, nearly entire leaves

5 veinsFlowers on spikes

Broadleaf plantain



L. C

lark



Alternate leaves

Deeply divided (dissected) leaves. Twice lobed.

L. C

lark

Neal and Carrawan 2004 NC State Univ Weeds n What is a weed? –A weed is a plant out of place.

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Transcript of Neal and Carrawan 2004 NC State Univ Weeds n What is a weed? –A weed is a plant out of place.