Weeds What is a weed? A weed is a plant out of place

What Do Weeds Do? Compete with crops for resources Interfere with crop quality and quantity Reduce aesthetics of landscape Affect function of turfgrass Displace native flora

Harbor insects and plant pathogens What Do Weeds Do? Ragweed pollen causes hay fever Cause allergies Harm people Harbor insects and plant pathogens

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: Wind People Rain runoff Birds and other animals Garden cultivation Mowing Topsoil or compost addition Purchased plants

Invaders - weed dispersal Wind Surface water Birds & animals Activities of man site prep, cultivation, planting

How we introduce and move weeds top soil organic amendments equipment plants

And, sometimes we intentionally introduce weeds Multiflora rose Crabgrass Kudzu

More Plants (weeds) Intentionally Introduced Water hyacinth Bamboo Japanese knotweed

The First Step in Weed Management is Identification The First Step in Weed Management is Identification! Weed Identification – Its More Than Knowing a Name!

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? 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 Resources For Piedmont and Coastal Plains Identifying Seedling and Mature Weeds in the Southeastern US Weeds of Southern Turfgrass Mountains Weeds of the Northeast

Identifying Seedling and Mature Weeds in the Southeastern US (AG-208) 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: 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: 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 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 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 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 Form http://www.cropsci.ncsu.edu/turffiles/weedid/weedid.htm http://www.cropsci.ncsu.edu/aquaticweeds/weed_id/aquatic.htm

Classification of Weeds

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

Lifecycles Annual Biennial Perennial

Life cycle of an annual weed Plant dies Seed Seedling Plant sets seed Plant flowers

Life cycle of a winter annual weed Summer Fall Plant dies Seed Seedling Plant sets seed Plant flowers

Common winter annual weeds

Life cycle of a summer annual weed Spring Fall Plant dies Seed Seedling Plant sets seed Plant flowers

Common Summer Annual Weeds J. Derr J. Neal J. Neal J. Neal

Life cycle of a biennial weed Plant dies Seedling Seed Second Season First Season Plant sets seed Plant flowers Over-winters as a rosette

Bull Thistle Queens Ann’s Lace Mullein Common Biennials J. DiTomaso R. Uva J. Neal

Life cycle of a perennial weed Roots/ rhizomes spread Seedling Seed Plant Over-winters Plant Flowers Plant sets Seed New plant

Some common perennial weeds R. Uva J. Neal R. Uva J. Neal J. Neal

Perennial Weeds Reproduce By: Seeds Tubers Bulbs Rhizomes Stolons

Types of Perennial Weeds Simple perennials Creeping perennials Rhizomes Stolons Creeping roots that produce shoots Tuberous perennials Bulbous perennials

Tap root or hardy fibrous root system Simple Perennials Spread by seed Tap root or hardy fibrous root system Examples: dandelion, plantain, dogfennel, pokeweed Tap root

Creeping Perennials Reproduce and spread by Stolon 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. Rhizome

Tuberous 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. Neal

Bulbous Perennials Persist through the dormant season as a bulb Wild garlic and wild onion produce bulblets, aerial bulblets, and seeds R. Uva

Weeds Are Also Classified By: Cotyledons (Seed leaves) Dicot (two seed leaves) Monocot (one seed leaf)

Monocots One seed leaf when plant emerges Long narrow leaves Parallel veins

Monocots -- Examples Grasses Onions Garlic Sedges Rushes Lilies Dayflower

Grasses Rounded or flattened stems and nodes Have fibrous root systems Some have fibrous roots, rhizomes or stolons for reproduction Growing point is below surface

Grasses are identified by: seedhead blade Grasses are identified by: sheath ligule auricles midrib collar stolon bud leaf crown rhizome

Vernation or Leaf Bud Rolled in the bud Folded in the bud

Ligules Absent Membranous Hairy The Scotts Co. The Scotts Co.

Ligules Absent Membranous Hairy

Auricle Absent Present Clasping The Scotts Co. The Scotts Co.

Seedheads Panicle Branched spike Spike The Scotts Co. The Scotts Co.

Seedheads Panicle Branched spike Spike

Grass-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.) A. Senesac 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 J. Neal

Yellow Nutsedge (Cyperus esculentus) R. Uva 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 J. Neal

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. Neal Forms tubers in “chains” J. Neal

Yellow vs. Purple – Leaf tips Yellow nutsedge leaf tips taper to a long, narrow point Purple nutsedge leaf tips are pointed but not tapered Yellow Purple J. Neal

Yellow vs. Purple -- Flowers Purple Nutsedge J. Neal Yellow Nutsedge J. Derr Purple or reddish brown turning black Yellow fading to tan

Wild Garlic (Allium vineale) R. Uva Wild Garlic (Allium vineale) Bulbous perennial Strong scent Reproduces by bulblets, rarely by seed Emerges in the winter and dies back in late spring or early summer J. Neal Aerial bulblets

Dicots or Broadleaf weeds Two seed leaves (cotyledons) Leaves have netted veins Largest group of weeds Often with bright showy flowers Exposed growing points

Unique Characteristics Growth Habit Leaf Orientation, Shape, Etc. How to ID Dicots Flowers Unique Characteristics Growth Habit Leaf Orientation, Shape, Etc.

Unique Characteristics R. Uva Unique Characteristics Look for: Thorns or spines Square or winged stems Compound leaves Whorled leaves Milky sap

Growth Habits J. Neal J. Neal Upright Spreading

Leaf Orientation Opposite Whorled Alternate Rosette

Simple Verses Compound Leaves R. Uva J. Derr Pinnate Palmate Simple Compound

Other Ways to Identify Cont. Leaf shape Leaf margin Toothed,entire,lobed, or deeply cut Petiole length Hair on leaves or other parts

Leaf Shapes, tips & bases

Shallow lobes or toothed Leaf Margins Deeply lobed Entire Shallow lobes or toothed J. Ditomaso R. Uva

Hairs – present or absent, & where? J. Neal J. DiTomaso Mouseear chickweed -- Hairs on stem & leaves Common chickweed -- Hairs absent

Tell Me What You See?

Broad, nearly entire leaves 5 veins Flowers on spikes Tell Me What You See? Rosette Broad, nearly entire leaves 5 veins Flowers on spikes Broadleaf plantain

Tell Me What You See? L. Clark

Tell Me What You See? Alternate leaves L. Clark Alternate leaves Deeply divided (dissected) leaves. Twice lobed.