Department of Crop and Soil Sciences - Cooperative Extension

Tests of commercially-available turfgrass cultivars and experimental selections are conducted annually at Penn State University to provide turfgrass managers, seed industry representatives, county extension agents, and other interested persons with information about turfgrass characteristics and performance.

In September 1990, 81 commercially available Kentucky bluegrass cultivars were established at the Joseph Valentine Turfgrass Research Center in University Park, PA. All entries were supplied by the National Turfgrass Evaluation Program, an organization established to coordinate the evaluation of turfgrass cultivars and experimental selections in many locations throughout the United States. The following is a report on the performance of Kentucky bluegrass cultivars from 1992 to 1994.

Kentucky bluegrass (Poa pratensis)

Kentucky bluegrass is a persistent and attractive turfgrass that is used in many home lawns, institutional grounds, parks, and athletic fields. This species has a medium to fine leaf texture and a medium to dark green color when properly fertilized. It produces extensive underground stems, called rhizomes, which provide good sod-forming characteristics and superior recuperative potential when compared to most other turfgrasses. Kentucky bluegrass is cold tolerant, wear tolerant, and moderately heat and drought tolerant. It makes optimum growth during the spring and fall and becomes semi-dormant under prolonged periods of heat and drought. It usually recovers quickly from dormancy with the advent of cooler temperatures and adequate soil moisture.

Kentucky bluegrass performs best when grown in well-drained soils and open, sunny areas. This grass does not tolerate poorly-drained soils or extensive shade (although a few varieties have improved shade tolerance).

Kentucky bluegrass generally requires a higher amount of nitrogen (N) fertilizer (2.0 to 4.0 lb N/1,000 sq ft per growing season) than other cool-season turfgrasses and tends to produce a significant amount of thatch. In most cases, Kentucky bluegrass should be maintained at 1.5 to 2.5 inches in height. However, during hot and humid conditions the mowing height should remain at or above 2.0 inches. The germination and establishment period for Kentucky bluegrass is slower than for most other turfgrasses, requiring up to two weeks for emergence.

Some of the more damaging diseases of Kentucky bluegrass are leaf spot, dollar spot, stripe smut, necrotic ring spot, and summer patch.

Some commercial seedlots have 'common Kentucky bluegrass' printed on the label. Common Kentucky bluegrass is a nonpedigree form consisting of many genetically different types. An upright grower, it is sensitive to low mowing heights and very susceptible to leaf spot diseases. The use of common Kentucky bluegrass may be justified where turf of high quality is not required and the height of cut will be at least two inches. Unfortunately, seed laws permit named varieties of Kentucky bluegrass to be sold as common Kentucky bluegrass. Some named varieties develop turf inferior to that of nonpedigreed Kentucky bluegrass but are extremely high seed yielders. For this reason, some seed producers grow and market named varieties as common Kentucky bluegrass.

Establishment and maintenance

Each entry was seeded in September, 1990 in 4 by 6 ft plots at a rate of 2.2 lb of seed per 1000 sq ft. The entire test area received full sunlight. Three replicate plots of each entry were used in this test. Plots were arranged in a randomized complete block design. Prior to seeding, starter fertilizer was applied at a rate of 1.0 lb of N, 0.5 lb of P205 (phosphate), and 0.5 lb K20 (potash) per 1000 sq ft. Preemergence herbicides were applied for crabgrass control in the spring of 1992,1993, and 1994. TrimecTM (2,4-D, MCPP, and dicamba) herbicide was applied in the spring of all three years to control broadleaf weeds. The test was mowed at 2.0 inches and fertilized twice each year (spring and fall) with 1 lb N/1000 sq ft per application. The test was irrigated whenever necessary to prevent wilting.

Evaluation and interpretation of results

All assessments of turfgrass performance were made on a visual basis. Care was taken to insure consistent and accurate evaluations. The following performance criteria were used to asses commercially-available Kentucky bluegrass cultivars.

Quality: Quality indicates the overall appearance of the turf and can incorporate several components including density, texture (measure of leaf width), uniformity, color, and freedom from disease and insect damage. Quality was rated using a scale of 1-9, where 9 = highest quality.

Spring green-up: Spring green-up provides an indication of how soon the turf breaks out of winter dormancy. The plots were rated for spring green-up using a scale of 1-9, with 9 = the most uniform green color.

Color: This rating reflects the inherent color of the entry, not yellowing or browning due to mower injury, drought stress, disease, etc. Color ratings are usually taken when grass is not under stress. Color was rated in the spring of 1993 and 1994 on a scale of 1-9, with 9 = the darkest green color.

Density: Density is a visual estimate of the number of plants per unit area (excluding diseased or insect-damaged patches of turf). Density was rated on a scale of 1-9, with 9 = the most dense turf.

Seedheads: Seedhead production under low mowing heights is generally considered undesirable. Seedheads were visually rated on a scale of 1 to 9 with 9 = the least number of seedheads.

Leaf spot disease: Leaf spot ratings provide an indication of a cultivar's reaction to this disease. Leaf spot disease ratings were based on a scale of 1-9 with 9 = no disease present and 1 = the entire plot severely affected.

Dollar spot disease: Dollar spot ratings provide an indication of a cultivar's reaction to this disease. Dollar spot disease ratings were based on a percentage scale (0 to 100) with 100% = the entire plot severely damaged.

Data for the above criteria are presented in Tables 1, 2, and 3. Entries are listed in order of the highest combined seasonal average quality for 1992, 1993, and 1994 to lowest seasonal average quality for the three years combined. Differences between two entries are statistically significant only if the LSD (Least Significant Difference) value, listed at the bottom of each column in Tables 1, 2, and 3, is exceeded by the numerical difference between two entries. For example, if cultivar 'A' is 3.0 units higher in quality than cultivar 'B', then this difference is only significant if the LSD value is 3.0 or less. If the LSD is greater than 3.0, then the numerical difference between the two cultivars may be due to inherent variability in the test area or some other element of chance.

Summary

Differences in performance criteria occurred among the Kentucky bluegrass entries during 1992-94. Owing to differences in growing conditions between 1992 and 1994, the performance of some cultivars varied among seasons. The 10 entries showing the best seasonal average quality over the three year test period were:

  1. Ascot
  2. Princeton 104
  3. NuStar
  4. Eclipse
  5. Preakness
  6. Unique
  7. Able I
  8. Blacksburg
  9. Midnight
  10. Glade

Cultivars showing the darkest green color were Midnight, Alpine, Noblesse, Ascot, and Able I. The lightest-green cultivars included A-34, Monopoly, Nassau, and Silvia. Dark green Kentucky bluegrasses should not be included in seed mixtures with light green cultivars if a uniform color is desired in the stand.

Some cultivars of Kentucky bluegrass produce seedheads during late spring and early summer. Seedheads are often considered undesirable and tend to detract from the appearance of the lawn. Cultivars with the greatest production of seedheads included Coventry, Unique, Buckingham, 1757, and Merit.

Most Kentucky bluegrass cultivars expressed high to moderate resistance to leaf spot and dollar spot dieases. However, some cultivars such as Kenblue, South Dakota Certified, Ronde, Cynthia, and Chelsea were severely damaged by leaf spot, resulting in considerable thinning and poor quality turf during spring and summer. Cultivars showing a high degree of dollar spot injury (>30% of the plot area affected in at least one of the three years of this trial) were Opal, Limousine, Julia, Pennpro, and Eva. Disease susceptibility and resistance in turf may vary considerably from year to year and from one location to another.

Keep in mind that the results of this test reflect cultivar performance for the management regime imposed at this site and environmental conditions in central Pennsylvania. Performance of the entries in this test may vary under different environmental conditions and management regimes.

Table 1. Seasonal average quality ratings of Kentucky bluegrass cultivars for 1992 through 1994. Trial established in September, 1990 at the Joseph Valentine Research Center, University Park, PA.
Entry Season ave.
1992
Season ave.
1993
Season ave.
1994
Combined
season ave.
1992-1994
¹LSD = least significant difference. The LSD values at the bottom of each column represent the minimum difference between any two entries necessary to be 95 percent confident that the difference is not attributable to chance.
Ascot 9.0 8.2 7.3 8.2
Princeton 104 8.0 8.0 7.9 8.0
NuStar 8.0 7.5 7.8 7.8
Eclipse 8.5 7.5 7.3 7.8
Preakness 8.5 6.8 7.7 7.7
Unique 7.7 7.1 7.9 7.6
Able I 7.8 7.7 7.3 7.6
Blacksburg 8.0 7.9 6.9 7.6
Midnight 7.8 7.3 7.3 7.5
Glade 8.2 7.2 7.1 7.5
Livingston 8.0 6.9 7.1 7.3
Alpine 7.5 8.0 6.5 7.3
Trenton 8.2 6.5 6.9 7.2
Banff 7.7 6.3 7.2 7.1
A-34 7.3 7.0 6.9 7.1
SR 2000 7.8 6.8 6.8 7.1
Eagleton 8.7 5.8 6.7 7.1
Bartita 7.3 7.3 6.5 7.0
1757 8.0 6.5 6.5 7.0
Haga 8.0 5.3 6.3 6.9
Aspen 8.0 6.2 6.4 6.9
Apex 6.7 7.4 6.5 6.9
Coventry 7.2 6.8 6.7 6.9
Challenger 6.8 6.6 7.1 6.8
Dawn 7.3 6.3 6.7 6.8
Allure 6.8 6.8 6.7 6.8
Touchdown 7.0 6.9 6.5 6.8
Liberty 7.7 6.3 6.5 6.8
Ram I 7.3 6.7 6.4 6.8
Marquis 7.5 6.6 6.3 6.8
Merit 7.5 6.6 6.3 6.8
Barblue 7.2 7.1 6.1 6.8
Fortuna 7.5 6.9 6.1 6.8
Gnome 7.5 6.8 6.1 6.8
Melba 7.0 7.7 5.8 6.8
Indigo 8.2 6.0 5.9 6.7
Washington 6.7 6.4 6.7 6.6
Georgetown 7.2 5.9 6.6 6.6
Baron 7.2 6.3 6.4 6.6
Trampas 6.7 6.8 6.4 6.6
Viva 7.5 6.1 6.3 6.6
Freedom 7.7 5.8 6.2 6.6
Noblesse 7.0 6.7 6.1 6.6
Abbey 7.5 6.2 6.1 6.6
Fairfax 7.2 6.6 6.0 6.6
SR 2100 7.7 6.4 5.6 6.6
Cobalt 7.7 6.4 5.6 6.6
Raven 7.3 6.9 5.5 6.6
Shamrock 5.7 7.2 6.5 6.5
4 Aces 7.0 6.4 6.1 6.5
Broadway 6.3 7.4 5.8 6.5
Kelly 6.8 6.5 6.0 6.4
Cannon 7.5 6.7 5.0 6.4
Caliper 6.8 5.9 6.2 6.3
Ampelia 5.8 6.7 6.3 6.2
Nassau 6.8 5.8 5.9 6.2
Estate 6.3 6.5 5.9 6.2
Miracle 7.0 5.9 5.7 6.2
Eva 5.5 7.8 5.2 6.2
Barmax 7.0 6.4 5.2 6.2
Suffolk 7.0 5.3 6.1 6.1
Barsweet 5.8 6.8 5.7 6.1
Pennpro 6.2 6.6 5.5 6.1
NuBlue 6.2 5.7 5.3 6.1
Crest 6.8 6.3 5.2 6.1
Julia 5.3 5.8 6.8 6.0
Merion 6.5 5.5 6.1 6.0
Destiny 6.8 5.7 5.5 6.0
Buckingham 7.0 5.8 5.3 6.0
Limousine 6.5 5.4 5.9 5.9
Classic 7.2 4.7 5.8 5.9
Minstrel 6.7 6.8 4.7 5.9
Cynthia 6.3 5.8 5.1 5.7
Opal 6.3 6.1 4.5 5.6
Silvia 5.8 5.2 5.3 5.4
Monopoly 6.0 4.9 4.7 5.2
Barzan 6.7 4.3 4.5 5.2
Chelsea 5.8 5.0 4.4 5.1
Ronde 5.7 3.8 4.3 4.6
South Dakota Cert. 6.3 3.3 4.2 4.6
Kenblue 5.7 3.4 3.9 4.3
LSD at 5% ¹ 1.1 1.0 1.1 ---
Table 2. Performance of Kentucky bluegrass cultivars for 1993 and 1994. Trial established in September 1990 at the Joseph Valentine Research Center, University Park, PA.
Entry Spring green-up
combined
season ave.
(1993/1994)
Color
combined
season ave.
(1993/1994)
Density
June 29
1993
Density
May 28
1994
Seedheads
combined
season ave.
(1993/1994)
Note: Refer to “Evaluation and interpretation of results” for an explanation of performance criteria ratings.
¹LSD = least significant difference. The LSD values at the bottom of each column represent the minimum difference between any two entries necessary to be 95 percent confident that the difference is not attributable to chance.
Ascot 4.7 8.0 8.0 7.3 7.2
Princeton 104 6.0 6.9 7.3 7.3 8.5
NuStar 5.0 6.4 7.7 7.0 8.0
Eclipse 5.7 6.7 7.0 6.7 8.8
Preakness 6.4 6.2 6.3 7.3 9.0
Unique 4.7 7.0 7.3 6.7 2.0
Able I 5.7 8.0 7.3 7.3 8.5
Blacksburg 4.4 6.9 7.7 7.0 8.8
Midnight 3.7 9.0 7.7 6.0 8.8
Glade 5.5 6.9 7.0 7.3 9.0
Livingston 6.2 6.2 6.7 6.7 7.3
Alpine 2.2 8.4 7.3 6.3 8.8
Trenton 6.5 4.7 7.0 8.0 6.6
Banff 6.8 4.9 7.0 8.0 7.3
A-34 6.7 3.2 7.0 7.7 9.0
SR 2000 5.4 7.4 6.0 6.7 8.3
Eagleton 6.0 5.5 5.3 4.0 9.0
Bartita 5.7 6.0 8.0 6.3 8.7
1757 6.4 6.4 7.0 6.3 3.6
Haga 6.2 4.7 6.3 6.0 6.6
Aspen 5.9 6.7 7.0 5.7 7.7
Apex 3.5 7.7 8.0 7.0 8.7
Coventry 6.2 4.7 7.3 7.7 1.0
Challenger 6.0 6.7 6.7 7.0 7.5
Dawn 6.2 5.0 6.3 6.0 5.3
Allure 5.5 4.7 7.3 7.7 9.0
Touchdown 6.0 4.4 8.0 7.7 9.0
Liberty 5.5 6.5 6.7 5.7 6.6
Ram I 5.9 6.4 7.0 5.0 9.0
Marquis 5.5 6.4 7.0 6.0 5.6
Merit 5.7 5.9 7.3 6.7 4.0
Barblue 5.7 5.5 7.7 7.0 8.7
Fortuna 4.7 6.5 6.7 5.3 8.0
Gnome 5.4 6.0 7.3 5.0 8.5
Melba 5.5 5.8 7.3 7.7 9.0
Indigo 5.3 7.4 6.3 5.7 5.6
Washington 6.7 4.5 6.3 7.3 9.0
Georgetown 5.5 4.7 7.0 5.0 5.6
Baron 4.7 5.3 6.3 7.0 7.8
Trampas 4.0 5.5 6.7 7.3 8.8
Viva 5.7 5.9 6.3 7.0 6.7
Freedom 6.2 4.5 6.7 6.7 5.1
Noblesse 4.2 8.2 7.0 5.7 8.0
Abbey 5.2 5.7 6.3 5.3 5.1
Fairfax 5.5 4.7 7.0 6.7 9.0
SR 2100 5.5 6.2 6.7 6.0 7.1
Cobalt 6.0 6.4 6.7 6.0 7.8
Raven 5.2 5.5 7.0 6.0 8.2
Shamrock 5.8 5.7 7.0 6.3 8.6
4 Aces 5.2 5.3 7.0 5.7 6.0
Broadway 2.4 6.7 7.7 6.0 8.8
Kelly 5.2 5.9 6.3 5.7 7.8
Cannon 4.9 5.4 6.3 4.3 7.3
Caliper 5.0 5.5 8.3 6.0 8.5
Ampelia 6.9 5.8 7.3 7.7 9.0
Nassau 6.0 7.4 6.7 5.7 5.3
Estate 5.5 4.0 7.0 6.7 9.0
Miracle 4.7 6.0 6.3 5.7 8.0
Eva 5.2 6.5 7.7 7.7 9.0
Barmax 5.2 4.8 6.3 7.3 8.8
Suffolk 5.3 4.7 7.0 5.3 4.2
Barsweet 4.2 5.9 7.7 6.3 6.5
Pennpro 5.7 4.7 8.7 7.1 9.0
NuBlue 5.0 5.7 6.7 6.3 9.0
Crest 5.0 6.4 7.3 4.7 6.3
Julia 5.0 5.5 8.0 8.0 8.5
Merion 5.2 5.9 6.7 6.7 6.7
Destiny 5.5 7.5 5.7 4.7 5.7
Buckingham 5.4 8.2 5.3 5.0 3.0
Limousine 4.7 5.0 9.0 8.3 9.0
Classic 5.3 4.9 6.3 5.0 5.0
Minstrel 5.5 7.2 7.0 5.7 9.0
Cynthia 5.9 6.0 8.0 5.0 9.0
Opal 4.7 7.0 7.3 6.0 8.8
Silvia 5.7 4.0 6.7 5.7 8.8
Monopoly 5.5 3.5 6.7 6.7 8.8
Barzan 2.8 5.9 2.7 3.7 4.8
Chelsea 5.3 7.5 6.0 5.7 7.3
Ronde 2.9 6.0 4.3 5.3 8.5
South Dakota Cert. 5.5 5.0 4.3 4.7 6.1
Kenblue 5.8 5.7 4.3 3.3 8.6
LSD at 5% ¹ 1.3 1.0 0.9 1.9 1.6
Table 3. Disease ratings of Kentucky bluegrass cultivars. Trial established in September 1990 at the Joseph valentine Research Center, University Park, PA.
Entry Leaf
spot
May 27
1993
% Dollar
spot
Aug 6
1992
% Dollar
spot
Aug 31
1993
% Dollar
spot
July 22
1994
Note: Refer to “Evaluation and interpretation of results” for an explanation of performance criteria ratings.
¹LSD = least significant difference. The LSD values at the bottom of each column represent the minimum difference between any two entries necessary to be 95 percent confident that the difference is not attributable to chance.
Ascot 9.0 0.0 1.7 4.0
Princeton 104 8.7 0.7 1.3 0.7
NuStar 7.7 0.0 1.0 0.7
Eclipse 9.0 1.0 1.7 2.7
Preakness 7.3 0.0 0.3 0.0
Unique 9.0 0.3 0.0 0.3
Able I 8.3 1.7 8.3 11.0
Blacksburg 8.3 0.3 4.7 7.3
Midnight 8.0 0.7 1.3 3.0
Glade 6.7 0.7 1.7 3.7
Livingston 8.0 0.3 0.3 3.0
Alpine 9.0 2.7 18.3 17.3
Trenton 8.3 0.3 1.3 2.0
Banff 8.0 0.0 1.7 0.3
A-34 7.7 1.0 1.7 0.7
SR 2000 9.0 1.0 2.3 13.0
Eagleton 5.3 0.0 1.0 0.3
Bartita 8.7 1.7 6.7 1.7
1757 9.0 0.0 0.3 1.3
Haga 8.0 0.0 1.3 4.0
Aspen 8.3 0.7 0.7 3.7
Apex 9.0 2.3 13.3 8.7
Coventry 7.3 1.3 3.3 7.0
Challenger 8.7 3.3 3.0 3.0
Dawn 8.0 0.7 3.3 1.0
Allure 7.0 2.0 9.3 15.0
Touchdown 9.0 3.0 5.0 12.3
Liberty 8.7 0.3 1.3 4.7
Ram I 8.0 0.0 9.0 11.0
Marquis 8.3 0.3 7.0 8.0
Merit 8.0 0.3 1.3 6.3
Barblue 8.7 0.7 1.7 27.3
Fortuna 8.0 0.7 1.0 6.0
Gnome 7.7 0.7 4.3 6.7
Melba 8.3 3.3 4.3 29.0
Indigo 8.3 0.0 3.7 3.7
Washington 7.3 1.0 3.7 1.3
Georgetown 8.3 1.3 0.3 3.7
Baron 8.0 0.7 0.7 1.3
Trampas 8.0 4.0 6.0 8.3
Viva 7.7 1.0 2.3 6.7
Freedom 7.7 0.0 2.0 1.3
Noblesse 8.7 0.7 1.7 7.3
Abbey 7.7 0.7 11.3 9.0
Fairfax 7.3 4.0 7.7 21.7
SR 2100 7.3 0.0 0.7 5.7
Cobalt 8.0 0.0 3.7 11.3
Raven 8.0 1.3 12.3 19.0
Shamrock 8.7 7.0 5.3 12.7
4 Aces 8.0 1.7 7.7 11.7
Broadway 8.7 12.0 6.3 20.0
Kelly 7.3 7.0 13.3 9.7
Cannon 7.3 1.0 5.3 16.0
Caliper 8.0 9.0 26.0 8.7
Ampelia 8.3 11.7 21.7 15.7
Nassau 9.0 1.3 1.7 1.3
Estate 7.7 4.7 10.3 21.7
Miracle 6.0 0.3 6.0 12.7
Eva 8.3 3.0 4.7 36.0
Barmax 7.3 1.0 0.0 11.3
Suffolk 6.3 0.0 3.7 2.0
Barsweet 6.3 20.7 15.0 5.3
Pennpro 9.0 11.0 20.0 36.0
NuBlue 7.7 2.3 20.3 11.0
Crest 8.7 3.7 11.7 10.7
Julia 8.0 31.7 28.3 10.3
Merion 8.0 2.7 16.3 10.7
Destiny 8.3 1.3 3.0 7.7
Buckingham 8.7 1.3 4.7 1.7
Limousine 7.7 2.7 40.0 30.0
Classic 8.3 0.7 0.7 2.3
Minstrel 8.7 7.0 11.3 26.0
Cynthia 4.7 6.0 7.0 12.7
Opal 8.3 7.7 20.3 73.3
Silvia 8.0 13.3 25.0 28.3
Monopoly 7.7 1.0 7.3 3.0
Barzan 5.3 0.3 1.0 0.0
Chelsea 5.0 9.3 11.0 13.0
Ronde 3.3 0.3 3.0 2.0
South Dakota Cert. 1.7 0.0 1.7 2.7
Kenblue 1.3 0.0 2.3 0.7
LSD at 5% ¹ 1.2 7.0 13.0 14.8

Prepared by Peter J. Landschoot, associate professor of turfgrass science.

Where trade names are used, no discrimination is intended and no endorsement by the Pennsylvania State University Cooperative Extension is implied.

Issued in furtherance of Cooperative Extension Work, Acts of Congress May 8 and June 30, 1914, in cooperation with the U.S. Department of Agriculture and the Pennsylvania Legislature. L.F. Hood, Director of Cooperative Extension, The Pennsylvania State University.

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