Lawns and Lawn Care
A lawn is It is an area of grass or mostly grass. It is mown, instead of allowing the plants to reach their full height. It is maintained for the benefit of people.
Lawns through history European in origin Scythed or cropped by animals Reel lawn mower Rotary mowers 40 hour work week Fertilizers and pesticides
Turf Facts of Concern In a recent study, half of households failed to read instructions on fertilizers and lawn pesticides Turf is the most fertilized plant in the world Between 1994 and 2004, an average of 75,884 people were injured using lawn mowers 50-70% of water is used to irrigate home landscapes
And some positive lawn facts Soil erosion and dust control Reduces runoff and enhances ground water recharge CO2 sink Temperature moderation Lowers fire hazard Withstands use
Sustainable Lawn Maintenance
Mowing Frequency Height Clipping Management Equipment
Mowing Frequency Don t do it based on a set schdule depends on growth rate of grass, environmental conditions, personal objectives, and cultivar May vary from twice a week to once every two weeks
Cutting Height Root mass is proportional to cutting height Lower cutting height leads to open turf and more weed, disease and insect depending on cultivar
Cutting Height
Cutting Height
0.5 1.0 1.5
.5 1.5
0.5 1.0 2.0
Clippings and Fertilization Grass blades are very nitrogen rich. Leave clippings to replace one fertilization a year.
Fertilization
Balanced NPK Unfertilized Balanced NPK + Fe
Weeds 1. Maintain a healthy vigorous turf. 2. Remove weeds manually. 3. Spot treat with herbicide 4. Pre-emergents for annual weeds only if really necessary
Lawn Establishment
What grass do I plant? Perennial Rye Fine blade Full sun Green year-round Not best for heavy use area Not shade tolerant
What grass do I plant? Fescue Turf Type Wider blade Full sun, but some shade tolerance Deeper rooted than rye Tolerates use well Somewhat shade tolerant
What grass do I plant? Rye & Fescue Mixture Sold as sun/shade mixture Full sun, but some shade tolerance Blends usually about 65% fescue and 35% perennial rye Somewhat shade tolerant
What grass do I plant? Kentucky Bluegrass not recommended in western Oregon except perhaps as part of a blend Warm season grasses should be avoided zoysia, bermuda, bahia, etc.
>Site Preparation - Till & Grade - No Till >Seeding/Sodding >Mulch >Fertilizer >Post Planting Care
Standard site conditions in Oregon
not even for sod
1 3 Till in amendments & fertilizer 2
A Quality Seed Bed Seeded and raked Seeded not raked
OSU mulch trials No Mulch Mulched Mulches hold seed in place. Speed germination Improve stand Uniformity.
Mulch type and depth affect development No mulch Lite Sawdust Hvy Sawdust Lite Compost Hvy Compost 17 days after planting
Deep mulch inhibits emergence of small seed
Mulch roller applying a light mulch
Straw
Searching for the optimum seed rate for P rye 2 lb 4 lb 6 lb
8 lb 10 lb 12 lb
6-8 lbs produces good dense turf Don t gain much above 10 lbs 8 lb 4 lb 4 lb seems to be practical minimum rate 20 lb 2 lb
Plant development is affected by seeding rate 20 lbs at 30 days after planting 6 lbs at 30 days
Establishment Fertilizer Trials Fertilizer response at 2 wks NPK 2 lb/1000 No Fertilizer
Establishment Fertilizer Trials Dark plots all received N +/- P & K P & K alone were equal to unfertilized plots
Site prep for sod is identical to prep for seed Green side up, seams tight together
Note crown bases for each plant
Ryegrass sod relies on netting to increase tensile strength
Irrigation should be applied to sodded lawns soon after planting to speed root development and to avoid foliar desiccation.
Seeding summary: >Optimum times= Aug 15 Sept 15 and May 1 June 15 >Mid summer is a bad time use treated seed or sod >Late fall plantings tend to be weedy and too soft to mow >Mulch is useful in cool weather/may cause damping off in hot weather. >Increase seed rate to replace mulch >Increase seed rate in late fall >Decrease seed rate in hot weather >Fertilize with N at planting and again 4-6 wks later
Full Sun Shade
Reduced tillering in shade
Reduced rooting in shade
In a situation that is generally shaded from surrounding trees, the added impact of dense seasonal shade from deciduous trees makes it almost impossible to grow functional turf.
The end result is complete loss of turf by the end of the growing season.
Debris accumulation under conifer trees causes thinning
Notice the amount of debris from Ponderosa pine needles that accumulates beneath the trees. This plus shade makes for a difficult site to grow grass.
Tree root competition for water
Often turf loss under trees is caused by root competition instead of shade.
Poor turf here has more to do with debris accumulation and drought stress than it does with shade.
Reduced wear tolerance in shade
Poor air movement increases disease
Leafspot
Fusarium patch
Before a nearby tree was uprooted in a storm, it was impossible to grow turf at this entrance to the rose garden.
Once the tree was gone the turf grew much better.
Good drainage, good air movement, and several hours of light each day make it possible to grow turf in otherwise shady areas.
With proper care even shady lawns can perform well. As rule mow on the high side, irrigate carefully avoiding excess moisture, and fertilize sparingly. Also adjust your expectations and accept the reality that turf in shade will rarely look as good as turf in full sun.
Sun flecks throughout the day can often provide enough light to sustain reasonably good lawns even if the site seems generally too shady.
Sometimes the best solution is to get rid of the lawn and develop a landscape filled with plants that grow well in the shade.
Western Oregon Lawns Regardless of what you plant all lawns go through a succession process resulting in the best adapted plants for that site
Factors in succession Plants that grow well fall, winter, & spring dominate turf over time
Bentgrass
Velvetgrass
Poa trivialis
Annual bluegrass
Common Climax Species Agrostis sp. Bentgrasses Poa trivialis Rough Bluegrass Poa annua Annual Bluegrass Holcus lanatus Velvetgrass Vulpia myuros Rat s Tail Fescue Various moss species Numerous dicot species
General Qualities of Climax grasses Look better at lower mowing heights Color is generally lighter green Generally require less fertilizer Most have limited drought resistance All form long lived soil seed bank Generally strong competitors
Early stages of encroachment (yr 2)
Enlarging patches of bentgrass (yr 3)
Bentgrass patches expanding (yr 3-4)
Encroaching grasses dominating (yr 5+)
10 yr old climax lawn in Seattle
60+ yr old climax lawn in Seattle
Source of encroaching grasses Contaminated seed eg. Poa trivialis in perennial rye Persistent soil seed bank eg. Poa trivialis Poa annua Bentgrasses Holcus
Potential transition end points Perennial Ryegrass High N Low N N responsive grasses dominate Low N responsive plants dominate Annual Bluegrass Climax Bentgrass, moss, clover Climax
Why does low N ryegrass get out competed? Brown Blight Rust Low N diseases cause turf thinning. Red thread
Why does low N ryegrass get out competed? Poor winter growth/loss of density
Why do bent & clover thrive in low N ryegrass? Ryegrass growth is weak while clover can fix its own N. Bentgrass has low N requirement.
Low N, Irrigated turf Bentgrass/Poa trivialis/clover climax
Potential transition end points Perennial Ryegrass High N Low N N responsive grasses dominate Low N responsive plants dominate Annual Bluegrass Climax Bentgrass, moss, clover Climax
Why does annual bluegrass dominate under high N? Fusarium patch Leafspot Turf thinning from high N diseases
Why does annual bluegrass dominate under high N? Turf thinning from Aggressive high N diseases winter growth
High N, irrigated Annual bluegrass climax
Summer drought impact Perennial Ryegrass Stand thins as ryegrass goes dormant. Some plants die. Drought tolerant dicots invade. Ryegrass stand thins to clumps. Weeds germinate in fall. Dominant grasses: Dryland bent Velvetgrass Rat s Tail fescue Dominant dicots: Clover False dandelion Common yarrow Mousear chickweed
Perennial rye clumping out Climax bent lawn in fall Bent rhizomes recovering Climax bent lawn in spring
White clover English daisy Black medic False dandelion Mousear Chickweed