Perennials Trial Report

North Carolina State University
Raleigh, North Carolina
2015–2016

JC Raulston Arboretum at
North Carolina State University
Raleigh, North Carolina

Mark Weathington
Director

Bernadette Clark
Agricultural Research Technician

Department of Horticultural Science
JC Raulston Arboretum

Table of Contents

General Introductory Notes and Acknowledgements
Understanding Our Data
Climate Graphs
Plant Material Sources
Results

General Introductory Notes and Acknowledgements

The Perennials Trial are located adjacent to the Color Trials at NC State University within the JC Raulston Arboretum (JCRA) in Raleigh. The JCRA is a ten and a half acre site administered by the Department of Horticultural Science and located on 35° 47'N latitude, longitude 78° 42' W, with an elevation of 400'.

Plants to be entered into our trials are received in one of three ways—seeds, rooted cuttings/plugs or finished plants/pot. Virtually all are grown within controlled greenhouse environments prior to placement in protected outdoor structures for hardening off. Plant spacing in the trials is based on the estimated mature size of entrant that fits to a 4' × 4' area or by the number of plants sent. Each entry is evaluated for two complete calendar years, being removed after the spring flush in year three. After the plants are established, they are evaluated for hardiness and landscape performance with ratings regularly taken.

Acknowledgements

We thank the vegetative and seed companies that participate in our trials. The services we provide would not be possible without the cooperation and support of these companies. We appreciate this confidence and trust and we look forward to continuing our partnership.

Lastly, we are thankful to other departmental staff and the volunteers of the JC Raulston Arboretum who assisted in transplanting and maintaining the plants … we couldn't have done it without you all!

Participants

2014

Dümmen Orange
Syngenta Flowers
Walters Gardens, Inc.

2015

Benary
Dümmen Orange
Syngenta Flowers

We also thank the following companies for their support of material donations:

  • BASF, 26 Davis Drive, Research Triangle Park, NC 27709
  • Sun Gro Horticulture, 3723 Hogshead Road, Apopka, FL 32702

Understanding Our Data

Cultural Data

Trials are conducted in amended beds. Prior to planting, beds are fertilized with 10-10-10 granular fertilizer and tilled. All plant material is mulched with composted leaf mulch to a 2"–3" depth after planting. Pre-emergent herbicides are used at the initial planting and repeated each subsequent spring/summer season. Hand weeding is done at all other times. Later in the season, a post-emergent herbicide application along the edge of the beds was done on an as needed basis. An in-ground irrigation system delivers 1"–1.5" of water to the beds each week. Plant height and width measurements (recorded in inches) are taken during the growing season. Data was collected from a representative plant, not the largest or the smallest but an average plant. Dormant plants were cut back in the fall/early winter to clean up the area and reduce overwintering habitat for insects and diseases.

Evaluations

The purpose of our perennials trial is to evaluate the plant material under conditions unique to our location. Our summer growing conditions are typically hot temperatures with high humidity. There is little nighttime temperature relief/recovery; average summer nighttime temperatures can be in the 70s. Irrigation is required all season.

Plants were given a visual rating by the same person. The overall rating was based on plant performance and appearance, including floriferousness, plant size and shape, and freedom from insect and disease problems. The rating scale ranged from 1 (very poor) to 5 (excellent) with 0.5 unit increments possible; a 0 rating indicated that all plants of the cultivar trial died.

What do we look for?

  • General Plant Growth – healthy appearance, attractive foliage, uniform growth
  • Flowers – floriferousness, bloom duration, uniform color, does it hold up after a heavy rain
  • Pests and diseases – any visible evidence of damage: distorted or chewed foliage
  • Heat tolerance – do the flowers and plants hold up in the heat, does the flower color fade or stripe
  • Hardiness (survival) – determined (in the spring) by the number of plants that made it through or emerged after the winter

Installation Date

Most entries were planted into their permanent trial location on:

  • 2014 entries on May 13, 2014
  • 2015 entries on May 12, 2015, and October 20, 2015

Entries that Did Not Survive

Died 2014

Heuchera 'Dolce Cinnamon Curls'
Lavandula angustifolia
'Sweet Romance'
Nepeta 'Cat's Meow'
Penstemon 'Arabesque Appleblossom'
Penstemon 'Arabesque Pink'
Penstemon 'Arabesque Red'
Penstemon 'Arabesque Violet
Phlox paniculata 'Early Dark Pink'
Phlox paniculata 'Early Purple'

Died 2015

Aubrieta 'Audrey Deep Blue Shades'
Aubrieta
'Audrey Red'
Campanula
'Pearl Deep Blue'
Campanula
'Pearl White'
Dianthus 'Odessa Orange Bling Bling'
Dianthus 'Odessa Easy Pink'
Lavendula 'Blue Scent Improved'
Lavenudula 'White Scent Early'
Penstemon 'Experiemental Arabesque Magenta'
Penstemon 'Experimental Red Dwarf'
Penstemon 'Experimental Violet Dwarf'
Salvia 'Salute IceBlue'

The best way to really evaluate our trials is to come in person. The JCRA is open 365 days a year.

Average Monthly Precipitation and Temperature

Precipitation Graph - 2011-2014

Temperature Grpah- 2011-2014

Cool spring temperatures (2015) led to slightly warmer than normal summer temperatures. In June, we experienced a 16-day period of temperatures at 95°F or above. The hottest temperature (102°F) occurred on June 16. The total number of days at or above 90 was 58, roughly 38% of our growing period. It was very humid, according to the meteorologists, the most humid summer in 20 years. The heaviest rainfall, which was 2.0", occurred on June 19. Rain totals for the summer season exceeded the norm by 3.65".

The winter season (2015–2016) was hard on the plants. In October and November, the temperatures were slightly warmer than normal but December was downright warm. The average daily temperatures during December were 12° higher than our normal (55.4°F vs. 42.8°F). On November 22, the first freezing event occurred, with a low temperature of 26°F.

Our cold period began in January. Our average night temperature for December was on par with the daytime highs of January and February. Even though the temperatures were in our normal range for both January and February, the plants were not well acclimated. Our coldest night, 15°F, was on February 14. We had relief in March with the return of warmer temperatures; the average daily temperature during March was 7°F higher than normal (57.3°F vs. 50.5°F).

Our precipitation in October, November, December, and February greatly exceeded (10.4") our normal amounts. Both January and March were below average. We ended the season with an excess of 8.8".

Seed and Plant Material Sources

Benary, 267 Osprey Drive, Pell City, Alabama, 35128
Dümmen Orange, 15245 W. Telegraph Road, Santa Paula, CA 93060
Syngenta Flowers, 6899 Winchester Circle, Suite 102, Boulder, CO 80301
Walters Gardens, Inc.
, 1992 96th Avenue, Zeeland, MI 49464

Please get in touch with these companies if you have specific questions regarding individual species and cultivars.

Trial Results

Perennials Planted in 2014

Summerific Cherry Cheesecake hibiscus 

Hibiscus
Summerific Cherry Cheesecake hibiscus 

Company
Walters Gardens
Year Planted
2014
Height
42.5"
Spread
44"
Number Planted
5
Survival
80%

Comments
Large (7"–8”), attractive flowers on compact (approximately 3.5' tall) plants; the flowers have a wavy look and are white with magenta veins; bloomed from June into September


Lavandula angustifolia 'Kerlavangem'
Sweet Romance English lavender

Company
Walters Gardens
Year Planted
2014
Number Planted
9
Survival
0%

Comments
Died 2014.


Nepeta ×faassenii 'Cat's Meow'
catmint

Company
Walters Gardens
Year Planted
2014
Number Planted
9
Survival
0%

Comments
Died winter 2014.


Penstemon hartwegii
Arabesque Appleblossom beardtongue

Company
Syngenta Flowers
Year Planted
2014
Number Planted
12
Survival
0%

Comments
Died winter 2014–2015.


Penstemon hartwegii
Arabesque Pink beardtongue

Company
Syngenta Flowers
Year Planted
2014
Number Planted
12
Survival
0%

Comments
Died winter 2014–2015.


Penstemon hartwegii
Arabesque Red beardtongue

Company
Syngenta Flowers
Year Planted
2014
Number Planted
12
Survival
0%

Comments
Died winter 2014–2015.


Penstemon hartwegii
Arabesque Violet beardtongue

Company
Syngenta Flowers
Year Planted
2014
Number Planted
12
Survival
0%

Comments
Died winter 2014–2015.


Phlox
Early Dark Pink hybrid garden phlox

Company
Dümmen Orange (Bartels)
Year Planted
2014
Number Planted
9
Survival
0%

Comments
Died winter 2014–2015.


Early Pink Dark Eye hybrid garden phlox

Phlox 'Barphlearpideye'
Early Pink Dark Eye hybrid garden phlox

Company
Dümmen Orange
Year Planted
2014
Height
10"
Spread
16.5"
Number Planted
9
Survival
33%

Comments
Low maintenance; compact clumps of green foliage; showy flower heads on sturdy stalks; flowers are a light pink color with dark pink centers; great flower power; flowered June through September.


Phlox 'Barphlopanearpur'
Early Purple hybrid garden phlox

Company
Dümmen Orange (Bartels)
Year Planted
2014
Number Planted
9
Survival
0%

Comments
Died winter 2014–2015.


Perennials Planted in 2015

Aubrieta
Audrey Red rock cress

Company
Syngenta Flowers
Year Planted
2015
Number Planted
12
Survival
0%

Comments
Never established; last plant died by February.


Pearl White Carpathian harebell

Campanula carpatica
Pearl White Carpathian harebell

Company
Benary
Year Planted
2015
Height
2.5"
Spread
6"
Number Planted
12
Survival
0%

Comments
Upward facing bell-shaped flowers; flower color is a clear white; flowered from end of June to late September; compact mounding habit. Died winter 2016.


Pearl Deep Blue Carpathian harebell

Campanula carpatica
Pearl Deep Blue Carpathian harebell

Company
Benary
Year Planted
2015
Height
3"
Spread
6"
Number Planted
12
Survival
0%

Comments
Beautiful, dark blue bell-shaped flowers facing upward; petite mounding habit; flowered from June to early September. Died winter 2016.


Clockwise Deep Blue Dalmatian bellflower

Campanula portenschlagiana
Clockwise Deep Blue Dalmatian bellflower

Company
Syngenta Flowers
Year Planted
2015
Height
2.5"
Spread
5"
Number Planted
12
Survival
8%

Comments
Compact plants with dainty, green leaves; deep blue bell-shaped flowers covered the plants; bloomed from August to mid-September.


Adiamo Yellow Red tickseed

Coreopsis grandiflora
Adiamo Yellow Red tickseed

Company
Syngenta Flowers
Year Planted
2015
Height
12"
Spread
14"
Number Planted
9
Survival
44%

Comments
Flowers are a bright yellow color; flowered from June through the end of August; flowers covered plants.


Leading Lady Lauren tickseed

Coreopsis
Leading Lady Lauren tickseed

Company
Dümmen Orange
Year Planted
2015
Height
10.5"
Spread
16"
Number Planted
6
Survival
50%

Comments
Plant forms a small mound; single flowers are a clear yellow color; bloomed from June to the end of October.


Leading Lady Charlize tickseed

Coreopsis
Leading Lady Charlize tickseed

Company
Dümmen Orange
Year Planted
2015
Height
10.5"
Spread
18"
Number Planted
6
Survival
100%

Comments
Plant forms a small mound; double flowers; flowers have frilly petals; flowers are a clear yellow color; bloomed from June to the end of November.


Odessa Easy Pink carnation

Dianthus
Odessa Easy Pink carnation

Company
Dümmen Orange
Year Planted
2015
Height
10"
Spread
8.5"
Number Planted
6
Survival
0%

Comments
Mounding plant habit; fringed flowers are dark pink centers and light pink edges; flowered June through late November. Died winter 2016.


Odessa Orange Bling Bling carnation

Dianthus
Odessa Orange Bling Bling carnation

Company
Dümmen Orange
Year Planted
2015
Height
8.5"
Spread
12.5"
Number Planted
6
Survival
0%

Comments
Attractive soft orange flower color; bloomed June through late November; mounding plant habit. Died winter 2016.


Odessa Pure carnation

Dianthus
Odessa Pure carnation

Company
Dümmen Orange
Year Planted
2015
Height
6.5"
Spread
8"
Number Planted
6
Survival
83%

Comments
Mounding plant habit; attractive clear white flowers; bloomed June through mid December.


Odessa Red carnation

Dianthus
Odessa Red carnation

Company
Dümmen Orange
Year Planted
2015
Height
6"
Spread
6"
Number Planted
6
Survival
0%

Comments
Attractive deep red with light red edge flowers; bloomed June through early November; mounding plant habit. Died winter 2016.


Odessa Pierrot carnation

Dianthus
Odessa Pierrot carnation

Company
Dümmen Orange
Year Planted
2015
Height
4"
Spread
7"
Number Planted
6
Survival
50%

Comments
Interesting fringed flowers that are purple with white edge color; bloomed June through mid December; mounding plant habit.


Odessa Bling Bling carnation

Dianthus
Odessa Bling Bling carnation

Company
Dümmen Orange
Year Planted
2015
Height
6.5"
Spread
8"
Number Planted
6
Survival
0%

Comments
Very attractive, light creamy flower color; bloomed June through late November; mounding plant habit. Died winter 2016.


Kahori pink

Dianthus
Kahori pink

Company
Dümmen Orange
Year Planted
2015
Height
3"
Spread
6.5"
Number Planted
6
Survival
100%

Comments
Attractive shape, nice and tidy; mounds of gray-green foliage with beautiful pink flowers that cover the plant; bloomed from June through late November.


Prairie Splendor Rose Compact coneflower

Echinacea purpurea
Prairie Splendor Rose Compact coneflower

Company
Syngenta Flowers
Year Planted
2015
Height
9.5"
Spread
9"
Number Planted
9
Survival
50%

Comments
Compact plant habit; flowers are a rosy-pink color; bloomed early July to late October.


Iberis sempervirens
Tahoe candytufts

Company
Syngenta Flowers
Year Planted
2015
Height
2.5"
Spread
4.5"
Number Planted
12
Survival
8%

Comments
One sole survivor; small clump covered in white flowers.


Lavandula angustifolia
White Scent Early lavender

Company
Syngenta Flowers
Year Planted
2015
Number Planted
9
Survival
0%

Comments
Never established; dead by late December.


Blue Scent Early lavender

Lavandula angustifolia
Blue Scent Early lavender

Company
Syngenta Flowers
Year Planted
2015
Height
8.5"
Spread
8"
Number Planted
12
Survival
0%

Comments
Compact plants with upright stems; foliage is a silvery-green color; fragrant, blue colored flowers; bloomed June through end of November. Died winter 2016.


Penstemon hartwegii
Experimental Arabesque Red Dwarf beardtongue

Company
Syngenta Flowers
Year Planted
2015
Number Planted
12
Survival
0%

Comments
Never established; dead by January.


Penstemon hartwegii
Experimental Arabesque Violet Dwarf beardtongue

Company
Syngenta Flowers
Year Planted
2015
Number Planted
12
Survival
0%

Comments
Never established; dead by January.


Penstemon hartwegii
Experimental Arabesque Magenta beardtongue

Company
Syngenta Flowers
Year Planted
2015
Number Planted
12
Survival
0%

Comments
Never established; dead by January.


Early White garden phlox

Phlox paniculata
Early White garden phlox

Company
Dümmen Orange
Year Planted
2015
Height
10.5"
Spread
10"
Number Planted
6
Survival
83%

Comments
Low maintenance; tight compact clumps of green; great flower power; flower color is a pure, clean looking white; flowered June through September.


Early Light Pink garden phlox

Phlox paniculata
Early Light Pink garden phlox

Company
Dümmen Orange
Year Planted
2015
Height
5.5"
Spread
10"
Number Planted
6
Survival
100%

Comments
Low maintenance; tight compact clumps of green; great flower power; flower color is a pale pink with a dark purple center; bloomed June through late October.


Spring White moss phlox

Phlox subulata
Spring White moss phlox

Company
Dümmen Orange
Year Planted
2015
Height
3.5"
Spread
8"
Number Planted
6
Survival
67%

Comments
Low maintenance; tight compact clumps of green; great flower power; flower color is pure white; bloomed August to September.


Spring Purple moss phlox

Phlox subulata
Spring Purple moss phlox

Company
Dümmen Orange
Year Planted
2015
Height
2"
Spread
6.5"
Number Planted
6
Survival
100%

Comments
Low maintenance; tight compact clumps of green; great flower power; bloomed November to January; flowers are purple.


Spring Light Pink moss phlox

Phlox subulata
Spring Light Pink moss phlox

Company
Dümmen Orange
Year Planted
2015
Height
2"
Spread
10"
Number Planted
6
Survival
100%

Comments
Low maintenance; tight compact clumps of green; has not flowered.


Spring Lavender moss phlox

Phlox subulata
Spring Lavender moss phlox

Company
Dümmen Orange
Year Planted
2015
Height
2.5"
Spread
9.5"
Number Planted
6
Survival
100%

Comments
Low maintenance; tight compact mound of green needle-like foliage; flowers are light purple center; great flower power; bloomed June to September.


Spring Dark Pink moss phlox

Phlox subulata
Spring Dark Pink moss phlox

Company
Dümmen Orange
Year Planted
2015
Height
3.5"
Spread
12"
Number Planted
6
Survival
100%

Comments
Low maintenance; tight compact mound of green needle-like foliage; great flower power; flower color is a deep pink; bloomed July through late January.


Spring Blue moss phlox

Phlox subulata
Spring Blue moss phlox

Company
Dümmen Orange
Year Planted
2015
Height
2"
Spread
9"
Number Planted
6
Survival
100%

Comments
Low maintenance; tight compact mound of green needle-like foliage; great flower power; bloomed December to January; flowers are soft blue with a dark blue center.


Early Pink Dark Eye hybrid garden phlox

Phlox 'Barphlearpideye'
Early Pink Dark Eye hybrid garden phlox

Company
Dümmen Orange
Year Planted
2015
Height
5.5"
Spread
9"
Number Planted
6
Survival
83%

Comments
Low maintenance; tight compact clumps of green; great flower power; bloomed June to September; flowers are light pink with a dark pink center.


Early Purple hybrid garden phlox

Phlox 'Barphlopanearpur'
Early Purple hybrid garden phlox

Company
Dümmen Orange
Year Planted
2015
Height
8"
Spread
8.5"
Number Planted
6
Survival
67%

Comments
Low maintenance; tight compact clumps of green; great flower power; bloomed June to late October; flowers are purple with a white center.


Salute Ice Blue sage

Salvia
Salute Ice Blue sage

Company
Dümmen Orange
Year Planted
2015
Height
7.5"
Spread
14"
Number Planted
6
Survival
0%

Comments
Compact, well branched plants; attractive spikes of blue/light purple flowers; bloomed from June to September. Died winter 2016.


Salute Pink sage

Salvia
Salute Pink sage

Company
Dümmen Orange
Year Planted
2015
Height
11"
Spread
20"
Number Planted
6
Survival
17%

Comments
Compact, well branched plants; attractive spikes of pink/light purple flowers; bloomed from June to September.


Salute Deep Blue sage

Salvia
Salute Deep Blue sage

Company
Dümmen Orange
Year Planted
2015
Height
7"
Spread
14"
Number Planted
6
Survival
50%

Comments
Short, well branched plants; prolific bloomer; flowers are a dark blue color; bloomed from June to September.


Solarity stonecrop

Sedum spurium
Solarity stonecrop

Company
Syngenta Flowers
Year Planted
2015
Height
3.5"
Spread
6"
Number Planted
9
Survival
100%

Comments
Ground cover that tightly hugs the ground; green fleshy leaves turn a beautiful crimson red in the winter; no flowers.


Surrender Red  common orpine

Sedum telephium
Surrender Red common orpine

Company
Syngenta Flowers
Year Planted
2015
Height
2.5"
Spread
4.5"
Number Planted
9
Survival
56%

Comments
Very compact, well branched plants; flowers are a deep rose/red color; flowered from September to November.