Perennials Trial Report

North Carolina State University
Raleigh, North Carolina
2020–2021

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

2019

Must Have Perennials
Terra Nova Nurseries

2020

Must Have Perennials
Sakata Seed America
Terra Nova Nurseries

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

• BASF, 26 Davis Drive, Research Triangle Park, NC 27709
• Sun Gro Horticulture, 4731 Homestead Place, Matthews, NC 28104

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. During our winters we can experience wide and rapid fluctuations in temperatures. Irrigation is required all season.

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:

• 2019 entries on April 23, 2019
• 2020 entreis on May 22, 2020

Entries that Did Not Survive

Died 2019

Aquilegia caerulea (Kirigami Rose and Pink)
Aquilegia caerulea (Kirigami Red and White)
Aquilegia caerulea (Kirigam iLight Blue and White)
Aquilegia caerulea (Kirigami Deep Blue and White)
Aquilegia caerulea (Kirigami Yellow)
Coreopsis (Satin and Lace Red Tapestry)
Iberis (Snowdrift)
Saxifraga ×arendsii (Alpino Early Magic Salmon)
Saxifraga ×arendsii (Alpino Early Rose)

Died 2020

Echinacea (Puff Vanilla)
Geum (Pretticoats Peach)
Geum (Tempo Yellow)
Helichrysum (Red Jewel)
Iberis sempervirens (Snow Cone Forte)
Leucanthemum maximum (Birdy)

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

The growing conditions during summer 2020 were excellent for growing plants. We experienced a cooler, wetter spring/early summer with a mild summer followed by a cooler and wetter late-summer which prolonged our growing season. We experienced impacts from multiple hurricanes throughout the growing season.

Our greatest daily amount of rainfall, 3.61", occurred on August 4, the second greatest was 3.47" on with September 1. Both rainfall totals are associated with hurricane occurrences.

We did not have any 100°F days. We had 55, 90°F+ days with the warmest being 96°F occurring three times, July 20, 27, and again on July 28.  We had a long stretch of mostly 90°+ days that occurred from June 21 through August 13 (only eight days in that period below 90°F and they were in the upper 80s).

Our "meteorological winter" (December–February) had above normal temperatures. The first freezing event occurred on November 19 with a low temperature of 30°F.   Our coldest temperature, 21°F, occurred on January 29. The longest stretch with freezing temperatures occurred early in the winter, from December 15 through December 19. Of particular note is the prolonged cold in January 2021- 16 days below freezing, 10 days hovering near freezing, and only 5 days in the low 40s.

Our greatest one-day rainfall during the winter months was 3.32” recorded on November 13.  We had no snow. 

Seed and Plant Material Sources

Must Have Perennials, 115 Third Street SE, Barberton, OH 44203
Sakata Seed America, 18095 Serene Drive, Morgan Hill, CA 95037
Terra Nova Nurseries, 10051 S. Macksburg Road, Canby, OR 97013

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

Trial Results

Perennials Planted in 2019

Echinacea 'TNECHCMY'
Cara Mia Yellow coneflower

Company

Terra Nova Nurseries

Year Planted

2019

Height

21"

Spread

27"

Number Planted

8

Survival

0%

Comments
Uniform, compact plant habit; double flowers are a bright yellow color; flowered from June through September; attracts butterflies and other pollinators.

Echinacea 'TNECHKW'
Kismet White coneflower

Company

Terra Nova Nurseries

Year Planted

2019

Height

10.5"

Spread

21"

Number Planted

8

Survival

62.5%

Comments
Compact and upright habit; white flowers with a golden-yellow eye; sturdy stems make for excellent cut flowers; flowered from June through September; attracts butterflies and other pollinators.

Geum 'TNGEUPP'
Pretticoats Peach garden avens

Company

Terra Nova Nurseries

Year Planted

2019

Height

5"

Spread

13"

Number Planted

7

Survival

0%

Comments
Compact habit; attractive large-leafed green foliage; semi-double peach colored flowers with ruffled petals; all plants dead by August 2020.

Geum 'Tngeuty'
Tempo Yellow garden avens

Company

Terra Nova Nurseries

Year Planted

2019

Number Planted

7

Survival

0%

Comments
Compact habit; large-leafed green foliage; clear yellow colored flowers; all plants dead by August 2020.

Heuchera 'TNHEULS'
Lemon Supreme coral bells

Company

Terra Nova Nurseries

Year Planted

2019

Height

5.5"

Spread

7"

Number Planted

7

Survival

0%

Comments
Compact, mounding habit; attractive yellow foliage that's good for brightening up any dark area in your garden!

Lychnis flos-cuculi 'Petit Henri'
ragged robin

Company

Must Have Perennials

Year Planted

2019

Height

2"

Spread

22"

Number Planted

6

Survival

83.3%

Comments
Uniform; compact green mounded plants; attractive small, fluffy, white, fringed-flowers are held well above the foliage; reliable, early spring flowering- flowered until the first of June!

Sedum telephium 'TNSEDDM'
Double Martini stonecrop

Company

Terra Nova Nurseries

Year Planted

2019

Height

17.5"

Spread

33"

Number Planted

12

Survival

83.3%

Comments
Compact, upright habit; green foliage with red tinged stems- more intense in the colder months; flowered from August to October.

Veronica 'TNVERB'
Venture Blue speedwell

Company

Terra Nova Nurseries

Year Planted

2019

Height

7"

Spread

36"

Number Planted

12

Survival

58.3%

Comments
Compact habit; tight, ground-hugging mounds with attractive, narrow-spiked, long-tapered blue flowers; flowered from June through September; easy to grow and low maintenance; great garden performance!

Dendranthema 'Autumn Spice Igloo'
garden mum

Company

Must Have Perennials

Year Planted

2019

Height

21"

Spread

36"

Number Planted

6

Survival

66.7%

Comments
Uniform, rounded mounds that require no pinching; Burnt-orange daisy-like flowers completely cover the green foliage; stunning when in bloom- mass plantings are a showstopper; flowered from August through October; low maintenance.

Dendranthema 'Brilliant Igloo'
garden mum

Company

Must Have Perennials

Year Planted

2019

Height

23.5"

Spread

36"

Number Planted

6

Survival

83.3%

Comments
Uniform, rounded mounds that require no pinching; Bright yellow daisy-like flowers completely cover the green foliage; stunning when in bloom- mass plantings are a showstopper in the garden!; flowered from August through October; low maintenance.

Perennials Planted in 2020

Buddleja 'Butterfly Gold'
butterfly bush

Company

Must Have Perennials

Year Planted

2020

Height

8.5"

Spread

12"

Number Planted

9

Survival

0%

Comments
Attractive bright-yellow and green variegated foliage; compact habit; purple flower spikes.

Delosperma 'Mountain Dew'
ice plant

Company

Must Have Perennials

Year Planted

2020

Height

3"

Spread

3.75"

Number Planted

9

Survival

33.3%

Comments
Ground-hugging succulent with prolific flowering from September through October; large clear-yellow, up-facing flowers with a white eye; low maintenance; shows great promise in tolerating/thriving in our heat and humidity.

Echinacea
Lovely Lolly coneflower

Company

Must Have Perennials

Year Planted

2020

Height

11"

Spread

15"

Number Planted

9

Survival

0%

Comments
Dark pink pompom-like flowers (with deep purple stems) flowering from July to October.

Heuchera ‘Steel City’
hybrid coral bells

Company

Must Have Perennials

Year Planted

2020

Height

4"

Spread

9"

Number Planted

12

Survival

66.7%

Comments
Beautiful, blue-green foliage; delicate pink flowers born above the foliage; the foliage discolored during the heat in late summer- ours are In full sun.

Leucanthemum ×superbum 'LEUZ0007'
Sunshine Freak! Shasta daisy

Company

Must Have Perennials

Year Planted

2020

Height

1.5"

Spread

3"

Number Planted

9

Survival

44.4%

Comments
Compact, well branched with dark green foliage; large daisy-like flowers that change from creamy light yellow to whiter; no pinching required.

Primula ×polyantha
Lighthouse Pink

Company

Sakata Seed America

Year Planted

2020

Height

4"

Spread

6"

Number Planted

7

Survival

85.7%

Comments
Compact, uniform habit; pink flower color; adds color to the garden in early spring- flowered until early May.

Primula ×polyantha
Lighthouse Rose

Company

Sakata Seed America

Year Planted

2020

Height

4"

Spread

5.5"

Number Planted

7

Survival

85.7%

Comments
Compact, uniform habit; rose flower color; adds color to the garden in early spring- flowered until early May.

Primula ×polyantha
Lighthouse White

Company

Sakata Seed America

Year Planted

2020

Height

3.5"

Spread

7"

Number Planted

7

Survival

85.7%

Comments
Compact, uniform habit; white flower color; adds color to the garden in early spring- flowered until early May.

Primula ×polyantha
Lighthouse Yellow

Company

Sakata Seed America

Year Planted

2020

Height

4.5"

Spread

7"

Number Planted

7

Survival

85.7%

Comments
Compact, uniform habit; yellow flower color; adds color to the garden in early spring- flowered until early May.