Cool Season Lawns

Kansas State University

By Bob Neier, Sedgwick County Extension Agent, Horticulture Adapted from materials by Ward Upham

Turfgrasses Commonly Grown in KS

▪Cool-Season

▸Turf Type Tall Fescue - Home lawns▸Kentucky Bluegrass▸Perennial Ryegrass - golf fairways▸Creeping Bentgrass - golf greens

▸Warm-Season - xeriscape

▸Zoysiagrass▸Bermudagrass▸Buffalograss

▪Difficult to grow either warm- or cool-season grasses well

Kansas in Transition Zone

Cool-Season Grasses

▪Grow best during spring and fall, summer difficult

Tall Fescue

▪Has mini-rhizomes but basically bunch grass

Tall Fescue

Tall Fescue

▪Best adapted cool-season grass in Kansas

▪Used on home lawns, parks and athletic fields

▪Propagated by seed and sometimes by sod▸Sod doesn’t hold together well and so either mix in

bluegrass or use plastic mesh at planting▸Seed germinates quickly; everything perfect, 4 days

▪Coarse bladed grass but newer cultivars better than old ones

▪Avoid K-31; coarser, less dense, lighter color and seed tends to be contaminated with orchard grass

Tall Fescue

Best Choice for the Shade

Tall Fescue

Major Problem: Brown Patch

What About Fine-Leaf Fescues?

▪There are tall fescues with finer leaves than K-31

▪There are true fine-leaved fescues▸Chewings fescue▸Hard Fescue▸Creeping Red Fescue▸Sheeps Fescue

True Fine-Leaf Fescues

▪Have excellent shade tolerance; better than any of our commonly grown turfgrasses.

▪Have poor heat tolerance. Do not come through our summers well.

Kentucky Bluegrass

Kentucky Bluegrass

▪Spreads by rhizomes

Kentucky Bluegrass

▪Fine-bladed grass that makes attractive lawn

▪Used on athletic fields, parks, and home lawns

▪Propagated by seed or sod

▪Poor heat tolerance▸Has trouble coming through our summers without

damage▸Better adapted further north

Kentucky Bluegrass

Numerous Problems: Summer Patch Can Be Severe

Cultural Practices

▪Mowing

▪Fertilization

▪Watering

▪Aerating

Mowing: Basic Information

▪Don’t remove more than 1/3 of blade at one time

Mowing: Basic Information

▪Don’t remove more than 1/3 of blade at one time

▪Clippings don’t contribute much to thatch (zoysia may be exception)

▪If remove clippings, must add 1/4 more nitrogen to get same response

▪Higher mowing height = deeper roots and less weeds for upright growing types

When to Fertilize Cool-Season Grasses

▪September

▸Most important fertilization of year

▸Use 1 pound nitrogen per 1000 square feet

▸Quick-release OK

▪November

▸Second most important fertilization

▸Use 1 pound nitrogen per 1000 square feet

▸Quick-release OK

▪April or May

▸Optional; use 1 pound of nitrogen per 1000 square feet

▸Use fertilizer with at least 1/4 nitrogen as slow-release

Fertilization: Fertilizer Analysis

▪Sequence of three numbers that reflect the percentage of nitrogen, phosphorus and potassium respectively.

Fertilizer: Macro Nutrients

▪Nitrogen - Used for above-ground growth and good green color

▪Phosphorus - Used for root growth and formation of seeds and fruit

▪Potassium - Used for basic plant growth and helps plants withstand stress

Lawn Fertilizers Fertilizer

▪21-0-0

▪Nitrogen usually needed

▪Phosphorus (middle number) usually already high in our soils and may run off and cause algae bloom in lakes

▪Potassium usually adequate in our soils

Most are high Nitrogen, low and phosphorus and potassium

Drop Spreader

▪Relatively easy to calibrate

▪Takes more time to apply fertilizer

▪Skips extremely obvious and so need to go over area 2 times at right angles

Whirlybird Spreader

▪Difficult to calibrate

▪Can apply fertilizer relatively quickly

▪Easier to avoid skips

▪With correct method, only need to go over area once

Watering▪Look for darker “hot

spots”. Often have purplish tinge.

▪Best to allow turf to undergo some stress early in season. Makes turf more drought resistant.

▪Attempt to apply 3/4 to 1 inch of water each time you irrigate.

Proper Watering

How to Tell if You Have Enough Water

▪Use catch cans

▪Use screw driver; moisture down 6 to 8 inches

Aeration Controls Thatch

▪Up to ½ inch thatch beneficial

▸Cushions plant▸Acts as mulch

▪Over ½ inch and roots tend to stay in thatch

Benefits of Aerating

▪Thatch control

▪Better root aeration

▪Quicker water infiltration

▪Relieves compaction

▪Deeper fertilizer placement

Aerators

▪Drum type normally used on home lawns

▪Go over lawn two times

Seeding

▪Normally done in early fall for cool-season grasses▸Soil is warm so faster germination and establishment▸Less weed problems

▸5-8 lb/1000 sq.ft. For tall fescue

Establishment

▪Seeding▸Commonly used for tall fescue and Kentucky bluegrass▸Sept is best month (may seed as late as Oct 15)▸March is second best month

▪Sodding▸Commonly used for Kentucky bluegrass▸Tall fescue is sodded more now▸Best success is Sept - late October, March through late

May

Overseed if > 50% Good Grass

▪July/August

▸Spray perennials with glyphosate

▪September

▸Fertilize then plant early in September (6-8 lb/1000sqft)

▸Core aerate if compacted, then seed and vertislice

▸Vertiseed if not compacted

▸Keep soil moist

▪October

▸Fertilize one month after planting

▪November

▸Fertilize again one month later

Overseeding

▪Normally done in early fall for cool-season grasses

▪Must have good seed-soil contact

▪Methods

▸Slit seeder

Overseeding/Vertislicing

▪Either put on seed prior to slicing or

▪ with vertiseeder

Seeding/Core Aeration

▪Lightly seed each time you aerate

▪Method to thicken up slightly thin lawns

Rototil & seed if < 50% Good Grass▪July/August

▸Spray perennials with glyphosate

▸Grade soil, apply nutrients, rototill

▪September

▸Fertilize then plant early in September (6-8 lb/1000sqft)

▸Rake in grass seed

▸Keep soil moist

▪October

▸Fertilize one month after planting

▪November

▸Fertilize again one month later

Sodding of Cool-Season Grasses

▪Best done in fall (just like for seeding) but can be done any time ground not frozen

▪Problems with laying sod in summer

▸Dessication (drying out)

▸Disease

▸Heat stress

▸Water bill

▪Prepare soil just like you would for seeding on bare ground

▪Roots will peg down in 7 to 10 days under good conditions

Weed Prevention

▪Maintain a thick turf

▸Weed seeds are often small and many need sunlight and consistent moisture to germinate

▸Even if weed seeds germinate in a thick turf, competition may slow weed growth

Weed Prevention

▪Maintain a thick turf

▪Mow as high as practical

Preemergence Herbicides

▪Applied before weeds germinate

▪Must be watered in

Preemergence Herbicides

▪Must be watered in

▪Only kills weed seeds as they germinate

▪Need some time after application for activation

▪Primarily used for annual grasses such as crabgrass

Common Preemergence Herbicides

▪Barricade

▪Dimension

▪Pendimethalin

▪Team

Control of Annual Grassy Weeds

Recommendations

▪Annual grassy weeds normally controlled with preemergent herbicides

▪Timing▸Traditionally, crabgrass preventers have been applied

by April 15th in central Kansas▸Apply when redbud trees are approaching full bloom

Control of Annual Grassy Weeds

▪Crabgrass

Control of Annual Grassy Weeds

▪Crabgrass

▪Goosegrass

▪Foxtail

Control of Annual Grassy Weeds

Miscellaneous Notes

▪Crabgrass seeds begin germinating when soil temperatures rise above 60Q F, and when air temperatures rise above 65Q for five consecutive days.

▪Barricade lasts a long time but takes longer to activate

▸Apply two weeks earlier than other herbicides▸Can be applied in fall for season long control next year

▪If late with preventer, use Dimension

Postemergence Herbicides

▪Applied after weeds are up

▪Rain can reduce or eliminate effectiveness

Common Postemergence Herbicides

▪2,4-D

▪Weed-B-Gon

▪Trimec products

▪Turflon products

▪Confront

Control of Broadleaf WeedsWinter Annuals

▪Henbit

Control of Broadleaf WeedsWinter Annuals

▪Henbit

▪Chickweed

Control of Broadleaf Weeds

Winter Annuals and Perennials

▪Henbit

▪Chickweed

▪Dandelion

Control of Broadleaf Weeds

What to Use▪2,4-D: dandelion and winter annuals in the fall

▪Combination products: dandelion and winter annuals in the early spring

▸Trimec (2,4-D + MCPP + Dicamba)

▸Weed-B-Gon (2,4-D + MCPP)

▪Confront (commercial product): excellent on clover, safe on buffalograss

▪Turflon products: good on clover

Control of NutsedgeBackground Info

▪Not a grass

▪Has triangular base

▪Likes moist sites

▪Can reproduce by seed or nutlets

Control of NutsedgeHerbicides

▪MSMA, Basagran and Manage are used

▪Manage works well

Control of Bermuda in Cool-Season Turf

Bermuda greens up late and goes dormant early

Control of Bermuda in Cool-Season Turf

Steps to Control

▪Mid-July: Fertilize and water bermuda

▪First of August: Spray with Glyphosate

▪Third weed of August: Spray again with Glyphosate if any green

▪Early September: Seed

Insect Problems

Most Common Problem is “Grubs”

▪May Beetle (June Bug)

▪Southern Masked Chafer

▪Billbugs

▪Black Turfgrass Ataenius

Grub Insects, Adults

May Beetle Southern Masked Chafer

Black Turfgrass Ataenius Billbug

White GrubsMottled appearance to turf

White Grubs

White Grubs

Identification

May BeetleSouthern Masked Chafer

May Beetle

▪3-year Life Cycle

▪2nd Year Most Damaging

Southern Masked Chafer

▪Annual grub

▪Most common grub that causes damage

▪Adults don’t feed that we know of

White Grub Control

Number needed to cause visible damage

▪Southern Masked Chafer: 8-9 per square foot

▪May Beetle: 3-4 per square foot

White Grub ControlMerit Insecticide

▪Labeled for white grubs and billbugs

▪Considered a 3 month product

▪If after annual grubs, apply early to mid- July

▪If also seeking to control May Beetle grubs or billbugs, apply no earlier than mid-May

▪Causes a disruption of a grub's nervous system resulting in its death

▪Not for rescue treatments

White Grub ControlMach 2 Insecticide

▪Labeled for cutworms, sod webworms, billbugs and white grubs

▪Considered a 6 week product

▪Apply early to mid- July for white grub control

▪Accelerates a grub's development by causing it to molt prematurely

▪Feeding stops within a couple of hours of ingestion

▪Not for rescue treatments

White Grub Control

Rescue Treatments

▪Apply when see damage

▪Use convential insecticide

How to Tell if Grub Affected by Insecticide

Grub on Way OutHealthy Grub

Diseases

▪Kentucky Bluegrass - Summer Patch, Dollar Spot

▪Tall Fescue - Brown Patch

▪Bermudagrass - Spring Dead Spot

▪Zoysiagrass - Large Patch

Kentucky Bluegrass - Summer Patch

Symptoms

▪Frog-eye Pattern

Kentucky Bluegrass - Summer Patch

Control

▪By the time you see symptoms, it is too late

▪Heritage and Bayleton provided good control when applied on May 1, May 27 and June 23.

Kentucky Bluegrass - Dollar SpotSymptoms

▪Small brown spots

▪Individual leaf blades have hourglass pattern

Kentucky Bluegrass - Dollar Spot

Conditions Favoring

▪Warm, humid conditions

▪Made worse by low nitrogen fertility

Kentucky Bluegrass - Dollar Spot

Control

▪On home lawns, usually not severe enough to warrant control.

▪May wish to apply light fertilization, if appropriate.

▪Many fungicides can be used if desired including Banner or Daconil.

Tall Fescue - Brown Patch

▪Smoke ring sometimes present in early morning

Symptoms

Symptoms

Tall Fescue - Brown Patch

▪Circular patches up to several feet in diameter

Tall Fescue - Brown Patch

Conditions Favoring

▪Hot days and warm nights

▪High nitrogen fertilization

▪Wet leaf surfaces

Tall Fescue - Brown PatchControl

▪Often turf will recover without spraying

▪Preventive sprays are more effective than curative

▪First preventive spray should go down about July 1

▪Heritage, Bayleton, Banner, ProStar, and Daconil work well. Daconil best for homeowner.

▪Heritage and ProStar have been the most effective over the long term (5 weeks control with one app)

Brown Area in Otherwise Green Lawn

If No Signs of Diseases or Insects, Probably Burn

▪Female dog

▪Gas spill

▪Car exhaust

▪Dumped salt water from ice cream maker

▪Shallow soil due to underlying rock

The End