2007 Annual Report

Horticulture Section

Dickinson Research Extension Center
1041 State Avenue
Dickinson, ND 58601

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Perennial Flower Performance
Sun vs. Shade

Jerry Larson and Frank Kukta
North Dakota State University Dickinson Research Extension Center


Landscape diversity is becoming increasingly important in local home yards, and other landscapes. The use of perennial flowers is much more popular in these diverse plantings that require planning design and appropriate plant selection. One of the first considerations is the preference of a sun or shady location, which included planting information. This can be difficult to determine because planting recommendations can range from sun to full shade for the same perennial. This situation resulted in the development of a DREC Project to evaluate performance of some perennials under Southwest North Dakota weather conditions.

This 2 year study will evaluate performance of 32 varieties of common perennial flowers in both sun and shade locations. Each variety was replicated twice. Plant characteristics to be evaluated will include: plant establishment, bloom periods, quality and overall bloom value, plant vigor, winter survival and related growth factors. Determining plant hardiness is the first factor to consider in selecting perennials. In order to determine this, the need for a least 2years of data is required. The main objective of this project is to report findings to interested gardeners. Hopefully this will result in increased interest in the use of perennial plants in home landscapes. Refer to Table #1 , for a list of varieties included in this study.


All perennials were planted in 4 X 8 ft. raised beds, with four plants per bed. The soil was amended with a 50-50- mix of top soil and high quality compost material (leaves and grass clippings compost) obtained from the Dickinson Landfill. Plants were fertilized on a monthly basis using ‘Miracle Gro' foliar applications. Weeds were controlled by hand-weeding on a as needed basis and in 2006 Preen granules were added twice during the growing season. Observation evaluations were conducted on a week – bi-weekly basis. Written evaluations were conducted twice during the first year and once in 2006.


The sunny location is located on the south end of the DREC garden. This site receives full sun during the day, with shade in early evening. The shade location is next to the north picnic grounds area. This received full shade until the ice storm of October 10, 2005. Following the storm a lot of trees had to be removed resulting in more sunny conditions. The planting dates were: Sun-June 24, 2005, and shade- June 27, 2005. Perennials at both locations were dead-headed as needed to encourage additional blooming. The plants were not cut-back in the fall to help catch added snow for winter protection.

Initially the sun location was hand-watered. A drip-irrigation system was added in mid-July to provide for more efficient use. The shade location was watered through the use of an automatic sprinkler system in each raised bed.


Year one sun location observation:

•  Plant survival was good 97%. However several perennials suffered from transplant shock, resulting in leaf scorch, browning and wilting of leaves and poor growth. This may effect winter survival.

•  Varieties showing the most stress with a (vigor rating) of 0 to 2 were: ‘Sun Ray' Lily- dead,

•  ‘Black Barlow' Columbine, ‘Aurea' Bellflower, ‘Matrona' Stonecrop, ‘Palace Purple' Coral Bells, ‘Happy Returns' Daylily, ‘Vision' Geranium, ‘White Clips' Bellflower, ‘Raspberry Wine' Bee Balm, ‘Garden View' Geranium and Lupine.

•  Varieties performing the best with a (vigor rating) of 4 to 5 were: ‘Varigata' Goldenrod, ‘Fireworks' Goldenrod, ‘Alexander' Yellow Loosestrife, ‘Prairie Dusk' Beard Tongue, ‘Brookside' Geranium, ‘Golden Pygmy' Leopard's Bane, ‘Garden Queen' Globeflower, ‘Frosted Violet' Coral Bells, ‘Spring Delight' Phlox, ‘Vera Jameson' Stonecrop, Soapwort, ‘Caesar's Brother' Siberian Iris, ‘Thriller' Lady's Mantle, ‘Huskers Red' Beardtongue, ‘Matrona' Stonecrop, and' Johnson's Blue' Geranium.

•  Insect pressure was very light with basically no damage. However some mite activity was documented.

•  Powdery Mildew was documented on ‘Raspberry Wine' Bee Balm. This indicates that environmental conditions and variety susceptibility are factors with mildew infections.


•  Overall plant survival was 97%. However many perennials were lacking vigor going into winter.

•  Disease was more prevalent in the shade location. Powdery mildew and leaf spot diseases were present the most. The effect of disease on winter plant survival will be evaluated in the spring of-2006.

•  Animal damage did occur in the shade location. Deer damage included clipping off the ends of plants and trampling damage.

•  Hardiness and winter survival will be evaluated in the spring of 2006.

•  Varieties showing the most stress with a vigor rating 0-2 were: ‘Sun Ray' Lily dead, ‘ Happy Returns' Daylily, ‘Prairie Dusk' Beardtongue, ‘Garden View' Bee Balm, ‘Golden Pygmy' Leopards Bane, ‘Giles Van Hees' Speedwell, ‘Spring Delight' Phlox, Soapwort, Lupine, ‘Aurea' Bellflower, ‘White Clips' Bellflower, ‘Woodside' Columbine, and ‘Chicago Heirloom' Daylily.

•  Top performing with a vigor rating of 4-5 were: Flag Iris, ‘Alexander', Yellow Loosestrife, ‘Matrona' Stonecrop, ‘Fireworks' Goldenrod, ‘Caesar's Brother' Siberian Iris, ‘Garden Queen' Globeflower, ‘Palace Purple' Coral Bell, ‘Vera Jameson' Stonecrop and ‘Husker Red' Beardtongue. See Table # 2 for year one evaluation data summary form.


The second year evaluation was conducted by Jerry Larson, DREC Horticulture Specialist, on June 16, 2006. Evaluation emphasis was for: Winter survival, plant vigor, foliage characteristics, and ornamental value rating along with relative comments.

Winter survival was comparable-sunny site 44% and shade site survival was 56%. Several factors may have contributed to this low survival. The use of raised beds provides for less root protection, snowfall was limited, extended periods of cold winter weather, freezing and thawing in the spring, and in some cases the perennial flowers were in a reduced vigor condition going into winter. No mulch was used which may have helped survival.

Varieties that performed well at both locations with all plants surviving were: Flag Iris, ‘Caesar's Brother' ‘Siberian Iris', ‘Lavender Flame' Speedwell, ‘Sun Ray' Lily and ‘Golden Queen' Globeflower. Perennials with no survival included: ‘Vision' Geranium, Soapwort, ‘Babyface' Phlox and ‘Raspberry Wine' Bee Balm. Varieties doing better in the sunny site were: ‘Prairie Dusk' Beardtongue, ‘Frosted Violet' Coral Bells and ‘Giles Van Hees' Speedwell. Plants preferring shade were: ‘Matrona' Stonecrop, ‘Happy Returns' Daylily, and ‘Black Barlow' Columbine. Refer to Table #3 for year 2 evaluation data.


This study documented that certain perennials perform differently in Shade vs Sun locations, while other do well in both sunny and shade sites. Overall, transplant shock was more common in sunny sites. This additional stress delayed plant development. Plants in the shade appeared to be in a more vigorous condition the first year. However winter survival was comparable at the two sites. The main concern in shade is the potential for disease. Winter survival for 2007 will be evaluated.




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