2003 Annual Report

Horticulture Section

Dickinson Research Extension Center
1089 State Avenue
Dickinson, ND 58601

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Xeriscape Ornamental Perennial Grass Trial for Low Water Use Landscaping

Llewellyn L. Manske and Jerry C. Larson
Range Scientist, NDSU, Dickinson Research Extension Center
Extension Agent, NDSU, Extension Service, Stark-Billings County

Western North America has increasing difficulty in providing adequate quantities of clean water for domestic use. A large portion of western municipalities' water supply is used for watering lawns, gardens, and landscape plants. Traditional landscaping frequently selects Kentucky bluegrass lawns and ornamental plants that require large amounts of water to remain beautiful. Several agencies and institutions joined Denver Water and the Associated Landscape Contractors of Colorado in 1981 to develop the concept of "Xeriscape" gardening. Alternatives to traditional techniques are being examined to develop landscapes that are harmonious with the local environmental conditions and use less water. Homeowners in western North Dakota have experienced the high costs of using domestic water for traditional landscape plants and have become aware of the need for alternative landscaping plants. Grass species in this trial are being tested and examined for use as plant material in low water use landscaping.

The purpose of Xeriscape gardening, or low water use landscaping, is to conserve expensive, precious domestic water by following seven simple commonsense principles.

Low water use landscaping achieves the desired goal of conserving water, money, leisure time, and precious resources while providing healthy, beautiful landscapes that add value to property. Xeriscape gardening combines landscaping with conservation.

Methods

This multi-year trial was designed to test and evaluate native grasses and adopted horticultural grasses as low water use ornamental landscape plants in western North Dakota. Thirteen native grasses and eleven horticultural domesticated grasses (Table 1) were included in this study. The research plots are located at the Dickinson Research Extension Center. These plots are managed with minimum maintenance, little supplemental irrigation water, no fertilizer, no herbicides after plot establishment, and hand roguing of weeds when necessary. The study consisted of three replications (Table 2). The grass plants were evaluated for vigor, ornamental value, seedhead aesthetics, color, and height. Vigor, ornamental value, and seedhead aesthetics were rated on a scale of 0-5 (Table 3). Color was recorded as one of twelve colors (Table 3). Total plant height was recorded as one of three height categories (Table 3). The twenty-four grass entries were randomly placed in plots in three replications (Table 4). Two evaluators rated each grass replication during initiation, early, mid-1, mid-2, late, and post growing-season periods.

Results

Mean evaluation ratings of grass entries are shown in Tables 5-8 for early, mid-1, mid-2, and late growing-season periods for 2002, respectively. Plants on replication plots of little bluestem, buffalo grass, Indiangrass, Canada wildrye, and sweetgrass died during the first year of the trial as a result of weakened condition caused by the plants' being covered by wood chips for several days and not receiving additional attention to assist the plants' recovery. These plants were replaced in the spring of 1999. Plants that expired from environmental conditions or natural causes were not replaced. The mean values of the evaluation ratings were determined for each growing-season period. Some ratings are reported with two mean values. The first value includes data from all three replications, and the second value includes data from only the active replications.

Most of the grass entries increased in vigor and ornamental value from initiation of growing-season, through mid-, and to late-season periods (Table 5-8). Several grass entries had medium to high vigor and ornamental value ratings during the initiation of growing-season period, and one entry--sweetgrass--had seedheads present in mid May. Vigor and ornamental value decreased for most grass entries after the late growing-season period (Tables 8). Several grass entries--blue grama, little bluestem, buffalo grass, sideoats grama, big bluestem, sand bluestem, prairie sandreed, Indiangrass, switchgrass, prairie cordgrass, Canada wildrye, sweetgrass, feather reed grass, ribbon grass, blue lyme grass, red switchgrass, autumn red, Altai wildrye, and pampas grass--had medium to high vigor and ornamental value ratings during the late growing-season period (Table 8). Most of the grass entries tended to have high seedhead aesthetics value ratings during the period from head-emergence to seed-development stages (Table 5-8). Several grass entries--blue grama, little bluestem, buffalo grass, sideoats grama, big bluestem, sand bluestem, prairie sandreed, Indiangrass, switchgrass, prairie cordgrass, Canada wildrye, feather reed grass, blue lyme grass, red switchgrass, autumn red, Altai wildrye, and pampas grass--had medium or high attractiveness of seedheads after reaching full maturity and during the late growing-season period (Table 8).

A few grass entries--sand love grass, giant silver banner grass, and zebra grass--had three or more sample periods with low vigor ratings and low ornamental values (Table 5-8). Several grass entries--blue grama, little bluestem, buffalo grass, sideoats grama, big bluestem, sand bluestem, prairie sandreed, Indiangrass, switchgrass, prairie cordgrass, sweetgrass, feather reed grass, ribbon grass, autumn red, Altai wildrye, and pampas grass--had three or more sample periods with high vigor ratings and high ornamental values (Table 5-8).

Most of the grass entries had distinctive attractive shades of green during the early, mid, and late growing-season periods (Tables 5-8). Many of the grass entries completed senescence during the late and post growing-season periods, displaying attractive shades of red, purple, or yellow before turning tan (Table 8).

The height categories for the grass entries (Table 9) were determined when the plants were mature and the seedheads had reached maximum height. Some of the grass entries grew relatively tall during the growing season of 2002. The grasses with seed heads taller than 6 feet were big bluestem, sand bluestem, prairie sandreed, prairie cordgrass, and pampas grass. Mature height of a plant is important in landscape design. The trial included three short-grass, thirteen mid-grass, and eight tall-grass entries.

Discussion

This is the fifth year of a multi-year trial designed to test and evaluate grass entries for use as ornamental plants for low water use landscaping. Most of the grass entries show positive potential for use as low water use landscaping plants. A few grass entries had one or more sample periods with low ratings, but these grasses should not be dismissed as landscape plants yet because the plants may improve. Some of the other grass entries may not maintain their moderate or high value ratings for the long run under these low maintenance and low supplemental water conditions.

Low water use landscaping, which uses native and/or adopted horticultural plants, is an important alternative to traditional landscaping, which uses plants that require large amounts of supplemental domestic water to remain beautiful. The results of this trial will assist homeowners in selecting ornamental perennial grass plants for use in their low water use landscaping.

The ornamental grass research plot at the Dickinson Research Extension Center has attracted lots of public interest. It is evident that the use of ornamental grasses in southwest North Dakota is steadily increasing. Local greenhouses and nurseries document this interest through increased sales of ornamental grasses. This acceptance is also evident through a windshield survey driving through Dickinson and surrounding areas.

Acknowledgment

The authors thank Ron Smith, NDSU Extension Horticulturist, Fargo, for providing plugs of horticultural adopted grass species plant material #13 to 20, for assisting with plot establishment, and for providing consultation during the development of this research project. We thank Craig Armstrong for providing plugs of horticultural adopted grass species plant material #22 and 23 and for providing advice on plot management. We thank USDA Plant Materials Center, Bismarck, for providing plugs of native species plant material #1 to 12. We thank Mike Knutson, USDA Plant Materials Center, Bismarck, for selection, collection, and delivery of native species plant material plugs and for assistance with plot establishment. We thank Jon Stika, NRCS, Area Agronomist, Dickinson, for making arrangements for native species plant material and for assistance with plot establishment. We thank James Nelson, DREC Animal Scientist, Dickinson, for preliminary preparation of plot area and for providing and spreading wood chips. We are grateful to Sheri Schneider for assistance in production of this manuscript. We are grateful to Amy M. Kraus and Naomi J. Thorson for assistance in preparation of this manuscript.

Table 1. Experiment identification number, common name, and scientific name of grasses included in xeriscape ornamental perennial grass trial for low water use landscaping.
1Blue grama'Bad River'Bouteloua gracilis
2Little bluestem'Badlands'Schizachyrium scoparium
3Buffalo grass'Bismarck'Buchloe dactyloides
4Sideoats grama'Pierre'Bouteloua curtipendula
5Big bluestem'Bison'Andropogon gerardi
6Sand bluestem'Garden'Andropogon hallii
7Prairie sandreed'Gosher'Calamovilfa longifolia
8Indiangrass'Holt'Sorghastrum nutans
9Switchgrass'Dacotah'Panicum virgatum
10Prairie cordgrass'Red River'Spartina pectinata
11Canada wildrye'Mandan'Elymus canadensis
12SweetgrassHierochloe odorata
13Feather reed grass'Karl Foerster'Calamagrostis acutiflora
14Ribbon grass'Feesey'Phalaris arundinacea
15Blue lyme grassElymus arenarius
16Sand love grassEragrostis trichodes
17Giant silver banner grass'Robustus'Miscanthus sacchariflorus
18Zebra grass'Zebrinus'Miscanthus sinensis
19Red switchgrass'Rehbraum'Panicum virgatum
20Autumn red'Purpurascens'Miscanthus sinensis
21Altai wildryeElymus angustus
22Pampas grassMiscanthus sacchariflorus
23Blue fescueFestuca cinerea
24Green needlegrassStipa viridula

 

Table 2. Experimental plot description for xeriscape ornamental perennial grass trial for low water use landscaping.
Location: Dickinson Research Extension Center, Dickinson, ND
latitude 46 53'N, longitude 102 49'W, elevation 2,500ft.
Replications:Three; Rep #1 West, Rep #2 Middle, Rep #3 East
Randomized Block Design
Study size:18' x 36'
Plot size:3' x 3'
Perimeter border:3'
Plot arrangement:2 columns with numbers 1-12 on west side and numbers 13-24 on east side of each replication.
Grass samples:24 types x 3 reps. = 72 plants
Plug planting date:5 May 1998 holes 12" diameter, 8" deep, planted as plugs.
Soil:Morton silt loam
Mulch:Wood chips applied at 4" to 6" thickness between plants.
Herbicide treatment:Roundup applied to previously existing grass cover 30 April 1998.
No other herbicides applied.
Fertilizer treatment:No fertilizer applied.
Soil amendments:No soil amendments applied.
Water:1.0 to 1.5 gallons water applied to each plot within 3.0 hours of planting. Minimum amount of irrigation water applied during growing season.
Weed control:Wood chips used between plants to help prevent weed growth.
Weeds will be hand rogued when necessary.
Pruning:Previous year senescent growth trimmed in early spring prior to rapid growth. Fall leaves of cool-season grasses not trimmed.

Table 3. Ratings scales used in the evaluation methods of this trial.

Plant Vigor Ratings Scale

543210
robust

vigor

medium vigorlow

vigor

dead

Ornamental Value Ratings Scale

543210
high

value

medium

value

low

value

zero

value

Seedhead Aesthetic Ratings Scale

5

43210
high

attractiveness

medium

attractiveness

low

attractiveness

not

present

Color Ratings

1. Drying5. Bluegreen9. Yellow Green
2. Dark Green6. Light Blue10. Light Red
3. Green7. Dark Blue11. Purple
4. Light Green8. Gold yellow12. Tan

Height Ratings Categories

Short grass
0.5 to 2.0 feet
Mid grass
2.0 to 3.0 feet
Tall grass
3.0 to 7.0 feet

 

Table 4. Location of grass entries in xeriscape ornamental perennial grass trial for low water use landscaping.

Rep. #1 West

Rep. #2 MiddleRep. #3 East
1

Blue

grama

3

Buffalo

grass

23

Blue

fescue

8

Indiangrass

18

Zebra

grass

16

Sand

love grass

4

Sideoats

grama

12

Sweetgrass

11

Canada

wildrye

9

Switchgrass

21

Altai

wildrye

20

Autumn

red

14

Ribbon

grass

15

Blue

lyme grass

24

Green

needlegrass

7

Prairie

sandreed

6

Sand

bluestem

23

Blue

fescue

2

Little

bluestem

11

Canada

wildrye

17

Giant silver

banner grass

14

Ribbon

grass

3

Buffalo

grass

5

Big

bluestem

5

Big

bluestem

6

Sand

bluestem

4

Sideoats

grama

22

Pampas

grass

19

Red

switchgrass

2

Little

bluestem

7

Prairie

sandreed

8

Indiangrass

16

Sand

love grass

10

Prairie

cordgrass

22

Pampas

grass

17

Giant silver

banner grass

13

Feather

reed grass

16

Sand

love grass

2

Little

bluestem

19

Red

switchgrass

10

Prairie

cordgrass

13

Feather

reed grass

9

Switchgrass

10

Prairie

cordgrass

12

Sweetgrass

5

Big

bluestem

8

Indiangrass

4

Sideoats

grama

17

Giant silver

banner grass

18

Zebra

grass

15

Blue

lyme grass

21

Altai

wildrye

1

Blue

grama

15

Blue

lyme grass

19

Red

switchgrass

20

Autumn

red

13

Feather

reed grass

1

Blue

grama

7

Prairie

sandreed

12

Sweetgrass

21

Altai

wildrye

23

Blue

fescue

18

Zebra

grass

3

Buffalo

grass

9

Switchgrass

11

Canada

wildrye

22

Pampas

grass

24

Green

needlegrass

20

Autumn

red

6

Sand

bluestem

24

Green

needlegrass

14

Ribbon

grass

 

Table 5. Mean evaluation ratings of grass entries in xeriscape ornamental perennial grass trial during the early growing-season period, mid June 2002.

Vigor Ornamental
Value
Seedhead
aesthetics
Color
12.72.7 0Green
23.53.5 0Green
34.35.05.0Gray Green
44.04.0 0Green
5 4.74.7 0Lt Green
64.04.0 0Green
73.73.7 0Dk Green
84.04.0 0Green
94.74.7 0Green
104.04.0 0Dk Green
114.04.03.0Green
125.05.05.0Yellow Green
135.05.00Dk Green
145.05.00Lt Green with Cream
152.72.74.0Blue
1600 0
1700 0
1800 0
192.32.3 0Green
204.74.7 0Green
214.74.34.5Blue
225.05.0 0Lt Green
232.02.02.3Blue
245.05.04.0Green

Split values: includes 3 reps./only active reps.
Evaluation
vigor: Low 16, 17, 18, 23
High 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 20, 21, 22
Ornamental value: Low 16, 17, 18, 23
High 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 20, 21, 22

Table 6. Mean evaluation ratings of grass entries in xeriscape ornamental perennial grass trial during the mid-1 growing-season period, mid July 2002.

Vigor Ornamental
Value
Seedhead
aesthetics
Color
13.03.00Green
24.04.04.0Green
34.34.74.0Gray Green
44.04.04.0Lt Green
5 5.05.05.0Green
65.05.05.0Bluegreen
74.34.04.3Bluegreen
84.04.30Green
95.05.05.0Green
105.05.00Dk Green
113.33.34.7Green
125.05.03.0Yellow Green
135.05.05.0Dk Green
144.75.04.0Lt Green with Cream
153.73.31.3Blue
16000
17000
18000
193.33.31.3Green
205.05.00Green
215.05.05.0Blue
225.05.00Lt Green
231.31.31.3Blue
245.05.05.0Green

Split values: includes 3 reps./only active reps.
Evaluation
vigor: Low 16, 17, 18, 23
High 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 19, 20, 21, 22
Ornamental value: Low 16, 17, 18, 23
High 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 19, 20, 21, 22

Table 7. Mean evaluation ratings of grass entries in xeriscape ornamental perennial grass trial during the mid-2 growing-season period, mid August 2002.

Vigor Ornamental
Value
Seedhead
aesthetics
Color
12.73.04.0Green with Tan
24.04.05.0Green and Red
34.34.03.5Gray Green with Tan
43.53.52.5Lt Green
5 5.05.05.0Green and Red
64.75.05.0Bluegreen
74.34.35.0Green
84.34.75.0Green
95.05.05.0Green and Yellow
105.05.05.0Dk Green
113.03.03.0Green
125.05.03.0Yellow Green
135.0 5.05.0Dk Green
145.05.00Lt Green with Cream and Pink
153.33.03.5Blue
16000
17000
18000
193.33.34.7Green and Red
205.05.00Green and Red
214.74.74.0Bluegreen
225.05.00Lt Green
231.01.00Blue
245.05.04.0Green

Split values: includes 3 reps./only active reps.
Evaluation
vigor: Low 16, 17, 18, 23
High 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 19, 20, 21, 22
Ornamental value: Low 16, 17, 18, 23
High 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 19, 20, 21, 22

Table 8. Mean evaluation ratings of grass entries in xeriscape ornamental perennial grass trial during the late growing-season period, mid September 2002.

Vigor Ornamental
Value
Seedhead
aesthetics
Color
13.03.04.0Lt Green and Tan
24.04.04.5Purple and Lt Green
3 4.34.04.0Gray Green and Tan
43.53.54.0Lt Green and Tan
5 5.05.04.7Red, Orange, and Lt Green
65.05.05.0Yellow Bluegreen
74.74.35.0Yellow Green
84.75.05.0Yellow Green
95.05.05.0Yellow
105.05.05.0Yellow Green
113.33.34.0Green
124.74.71.0Yellow Green
135.05.05.0Green
145.05.02.0Lt Green with Cream
153.52.33.0Blue
16000
17000
18000
193.73.74.3Lt Green and Red
205.05.05.0Lt Green and Orange
215.05.03.3Blue
225.05.05.0Yellow, Orange, and Lt Green
232.02.00Blue
245.05.04.0Green

Split values: includes 3 reps./only active reps.
Evaluation
vigor: Low 16, 17, 18, 23
High 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 19, 20, 21, 22
Ornamental value: Low 16, 17, 18, 23
High 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 19, 20, 21, 22

Table 9. Plant height category of grass entries in xeriscape ornamental perennial grass trial.
Height Category

Code

1S
Short grass 0.5-2.0 ft.
2M
Mid grass 2.0-3.0 ft.
3S
Short grass 0.5-2.0 ft.
4M
Mid grass 2.0-3.0 ft.
5T
Tall grass 3.0-7.0 ft.
6T
Tall grass 3.0-7.0 ft.
7T
Tall grass 3.0-7.0 ft.
8T
Tall grass 3.0-7.0 ft.
9T
Tall grass 3.0-7.0 ft.
10T
Tall grass 3.0-7.0 ft.
11M
Mid grass 2.0-3.0 ft.
12M
Mid grass 2.0-3.0 ft.
13M
Mid grass 2.0-3.0 ft.
14M
Mid grass 2.0-3.0 ft.
15M
Mid grass 2.0-3.0 ft.
16M
Mid grass 2.0-3.0 ft.
17T
Tall grass 3.0-7.0 ft.
18M
Mid grass 2.0-3.0 ft.
19M
Mid grass 2.0-3.0 ft.
20M
Mid grass 2.0-3.0 ft.
21M
Mid grass 2.0-3.0 ft.
22T
Tall grass 3.0-7.0 ft.
23S
Short grass 0.5-2.0 ft.
24M
Mid grass 2.0-3.0 ft.

Reference Literature

Barondeau, D., R. Smith, J. Larson, C. Miller, J. Dohrmann, T. Becker, R. Gaebe, B. Schmidt, J. Buckley, and L. Manske. 1997. Xeriscape plant selection. NDSU Extension Service, Fargo, ND. 22 min. Video tape.

Denver Botanic Gardens. No date. Water-smart gardening. Brochure. Denver Parks and Recreation Department, Denver, CO.

Denver Water. 1996. Xeriscape plant guide. American Water Works Association. Fulcrum Publishing, Denver, CO.

Denver Water. No date. Discover xeriscape. Pamphlet. Xeriscape Colorado Inc., Denver, CO.

Denver Water. No date. Efficient irrigation systems at work. Pamphlet. Office of Water Conservation, Denver, CO.

Hill, L., and N. Hill. 1995. Lawns, grasses and ground covers. Rodale Press, Emmaus, PA.

Plant Materials Center. 1997. Native grasses for prairie landscaping in the Northern Great Plains. Brochure. USDA Natural Resources Conservation Service, Bismarck, ND.

 

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