Perennials Trial Report

North Carolina State University
Raleigh, North Carolina
2021–2022

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

2020

Must Have Perennials
Sakata Seed America
Terra Nova Nurseries

2021

Ball Seed Co.
Must Have Perennials
Gardenchoice
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:

• 2020 entries on May 22, 2020
• 2021 entries on May 11, 2021

Entries that Did Not Survive

Died 2020

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

Died 2021

Buddleja (Butterfly Gold)
Delosperma (Orange Crush)
Echinacea (Lovely Lolly)
Primula ×polyantha (Lighthouse Blue, L. Rose, L. Yellow)
Lysimachia congestiflora (Firefly)

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 2021 summer season growing conditions were mild. The rain at times was significant, but not record breaking (generally a result of tropical depressions or hurricanes). Our greatest daily amount of rainfall, 3.3", occurred on July 9.  

We did not have any 100° days. We had fifty 90°F+ days with the warmest being 97°F occurring on August 29. We had three long stretches of 90°+ days that occurred from May 22 through May 28, July 6 through July 17, and August 19 through August 31. August had the most 90°+ days at 18 days.  

Our winter weather started out as warm and dry then was replaced by a much cooler and wetter pattern in January then flipped back to warm and dry. We had three impactful winter storms in January (3, 16, and 21) making it one of the snowiest months in many years. Greatest snowfall was 2.7" on January 21.  The period from December 2021 to February 2022 ranks as our 15th-warmest and 33rd-driest winter since 1895 when recordkeeping started. Spring finished with a summer-like feeling as hot weather had a firm foothold in May. Our first 90-degree day of the year occurred on May 19. May ended with six days at or above 90°F.   This was our 10th-warmest spring since 1895. Spring had 31 days with high temperatures at or above 80°F.

Seed and Plant Material Sources

Ball Seed Co., 622 Town Road, W. Chicago, IL 60185
GardenChoice, 939 Helen Ruth Drive, Fort Wright, KY 41017
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 2020

Delosperma 'Mountain Dew'
ice plant

Company

Must Have Perennials

Year Planted

2020

Height

3"

Spread

14.5"

Number Planted

9

Survival

11%

Comments
Ground-hugging succulent with prolific flowering summer into fall; large clear-yellow, up-facing flowers with a white eye; low maintenance.

Heuchera 'Steel City'
coral bells

Company

Must Have Perennials

Year Planted

2020

Height

11"

Spread

19"

Number Planted

12

Survival

67%

Comments
Beautiful, blue-green foliage; a mass of delicate pink flowers born above the foliage in early spring; Mass plantings draw your attention; the foliage may discolored during the heat of late summer- ours are In full sun.

Leucanthemum ×superbum 'LEUZ0007'
Sunshine Freak! Shasta daisy

Company

Must Have Perennials

Year Planted

2020

Height

8"

Spread

12.5"

Number Planted

9

Survival

11%

Comments
Compact, well branched with dark green foliage; large daisy-like flowers that change from creamy light yellow to white; flowers from spring into early summer; love the range of flower colors that completely cover the plants; no pinching required.

Primula ×polyantha
Lighthouse Pink primrose

Company

Sakata Seed America

Year Planted

2020

Height

4"

Spread

6"

Number Planted

7

Survival

28%

Comments
Compact, uniform habit; pink flower color; adds great early color to the garden.

Perennials Planted in 2021

Artemisia gmelinii 'Balfernarc'
SunFern Arcadia Russian wormwood

Company

Ball Seed Co.

Year Planted

2021

Height

6"

Spread

13"

Number Planted

9

Survival

100%

Comments
Mounded plant habit with fern-like foliage that thrives in full sun; low maintenance; winter hardy.

Artemisia gmelinii 'Balfernlym'
SunFern Olympia Russian wormwood

Company

Ball Seed Co.

Year Planted

2021

Height

7.5"

Spread

21.5"

Number Planted

9

Survival

100%

Comments
Mounded plant habit with fern-like foliage that thrives in full sun; low maintenance; winter hardy.

Brunnera 'Alexandria'
Siberian bugloss

Company

Terra Nova Nurseries

Year Planted

2021

Height

5.5"

Spread

7.5"

Number Planted

9

Survival

33%

Comments
Light sky blue flowers above silvery heart shaped foliage that have deep green veins; flowers in early spring; brightens up a shady area; deer resistant.

Buddleja 'Balchryink'
Chrysalis Pink butterfly bush

Company

Ball Seed Co.

Year Planted

2021

Height

7.5"

Spread

13.5"

Number Planted

5

Survival

100%

Comments
Compact plants with a mounding habit; produces a profusion of pink colored flowers that bloom from early summer to early fall; great for attracting bees, butterflies, and other pollinators; low maintenance.

Buddleja 'Balchryite'
Chrysalis White butterfly bush

Company

Ball Seed Co.

Year Planted

2021

Height

12"

Spread

15"

Number Planted

5

Survival

60%

Comments
Compact plants with a mounding habit; produces a profusion of clear white colored flowers that bloom from early summer to early fall; great for attracting bees, butterflies, and other pollinators; low maintenance.

Buddleja 'Balchrylu'
Chrysalis Blue butterfly bush

Company

Ball Seed Co.

Year Planted

2021

Height

12"

Spread

18"

Number Planted

5

Survival

80%

Comments
Compact plants with a mounding habit; produces a profusion of purple-pink colored flowers that bloom from early summer to early fall; great for attracting bees, butterflies, and other pollinators; low maintenance.

Buddleja 'Balchryran'
Chrysalis Cranberry butterfly bush

Company

Ball Seed Co.

Year Planted

2021

Height

9.5"

Spread

17"

Number Planted

5

Survival

100%

Comments
Compact plants with a mounding habit; produces a profusion of beautiful ddep red/cranberry colored flowers that bloom from early summer to early fall; great for attracting bees, butterflies, and other pollinators; low maintenance.

Buddleja 'Balchryurp'
Chrysalis Purple butterfly bush

Company

Ball Seed Co.

Year Planted

2021

Height

8.5"

Spread

14"

Number Planted

5

Survival

60%

Comments
Compact plants with a mounding habit; produces a profusion of pink-purple colored flowers that bloom from early summer to early fall; great for attracting bees, butterflies, and other pollinators; low maintenance.

Coreopsis 'Baluptred'
UpTick Red tickseed

Company

Ball Seed Co.

Year Planted

2021

Height

11"

Spread

14"

Number Planted

9

Survival

100%

Comments
Mounding habit; gorgeous bicolored flower- red petals tipped in yellow; profusion osf single blossoms cover the plants from late spring then sporadically through early fall; attracts bees, butterflies, and other pollinators; low maintenance; heat tolerant; mildew resistant

Delosperma 'T18-2'
Ocean Sunset Orange Vibe ice plant

Company

Ball Seed Co.

Year Planted

2021

Height

4"

Spread

14.5"

Number Planted

9

Survival

100%

Comments
Spreading plant habit; lots of flower power- flowers are closed at night and open mid-morning; electric orange flowers with a yellow center that bloom from late spring then sporadically through early fall; great for rock gardens- eye catching flower color and drought tolerant; heat tolerant, low maintenance.

Delosperma 'T18-5'
Ocean Sunset Violet ice plant

Company

Ball Seed Co.

Year Planted

2021

Height

4.5"

Spread

11.5"

Number Planted

9

Survival

100%

Comments
Spreading plant habit; lots of flower power- flowers are closed at night and open mid-morning;vivid violet-pink flowers with a yellow center that bloom from late spring then sporadically through early fall; great for rock gardens- eye catching flower color and drought tolerant; heat tolerant, low maintenance.

Delosperma 'T18-7'
Ocean Sunset Orange Glow ice plant

Company

Ball Seed Co.

Year Planted

2021

Height

3.5"

Spread

16"

Number Planted

9

Survival

100%

Comments
Spreading plant habit; lots of flower power- flowers are closed at night and open mid-morning; brilliant pink flowers with a yellow center that bloom from late spring then sporadically through early fall; great for rock gardens- eye catching flower color and drought tolerant; heat tolerant, low maintenance.

Dianthus 'G18139'
EverBloom Watermelon Ice pink

Company

GardenChoice

Year Planted

2021

Height

4.5"

Spread

5"

Number Planted

9

Survival

100%

Comments
Tidy, mounding habit- very controled growth/spread; very compact; single, fringed flowers are bright pink with a narrow band of white; blooms from late spring then sporadically through early fall; good for use in rock gardens; deer resistant; low maintenance.

Dianthus 'G18144'
EverBloom Strawberry Tart pink

Company

GardenChoice

Year Planted

2021

Height

4.5"

Spread

7"

Number Planted

9

Survival

100%

Comments
Tidy, mounding habit- very controled growth/spread; very compact; single, fringed flowers are pink with dark pink centers; blooms from late spring then sporadically through early fall; good for use in rock gardens; deer resistant; low maintenance.

Dianthus 'G18146'
EverBloom Plum Glory pink

Company

GardenChoice

Year Planted

2021

Height

5"

Spread

6.5"

Number Planted

9

Survival

100%

Comments
Tidy, mounding habit- very controled growth/spread; very compact; single, fringed flowers are violet-pink with red eyes and edged in white; blooms from late spring then sporadically through early fall; good for use in rock gardens; deer resistant; low maintenance.

Echinacea 'Giddy Pink'
coneflower

Company

Terra Nova Nurseries

Year Planted

2021

Height

4"

Spread

4.5"

Number Planted

9

Survival

67%

Comments
Bright pink, double flowers cover the plant from late spring then sporadically through early fall; well branched; nice study stems; deer resistant; great for attracting pollinators.

Echinacea 'Moab Sunset'
coneflower

Company

Terra Nova Nurseries

Year Planted

2021

Height

13"

Spread

5.5"

Number Planted

9

Survival

44%

Comments
Compact plants with an upright habit; large, double orange colored flowers blanket the plant with color from late spring then sporadically through early fall; can use for cut flowers; deer resistant; great for attracting pollinators.

Echinacea 'TNECHDSW'
Dark Shadows Wicked coneflower

Company

Terra Nova Nurseries

Year Planted

2021

Height

7.5"

Spread

8"

Number Planted

9

Survival

22%

Comments
Very upright habit; attractive pink flowers atop green foliage bloom from late spring then sporadically through early fall; can be used for cut flowers; stunning when planted en mass; deer resistant; great for attracting pollinators.

Echinacea 'TNECHPS'
Prima Saffron coneflower

Company

Terra Nova Nurseries

Year Planted

2021

Height

8"

Spread

8"

Number Planted

9

Survival

44%

Comments
Compact plants; daisy-like flowers that are an intense, bright, clear yellow color that bloom from late spring then sporadically through summer; deer resistant; great for attracting pollinators.

Echinacea 'TNECHSDR'
Sunny Days Ruby coneflower

Company

Terra Nova Nurseries

Year Planted

2021

Height

8"

Spread

12"

Number Planted

9

Survival

100%

Comments
Upright habit, topped with very large deep red flowers that bloom from late spring then sporadically through early fall; sturdy stems support the over-sized double flowers; deer resistant; great for attracting pollinators.

Echinacea 'TNECHSS'
Sweet Sandia coneflower

Company

Terra Nova Nurseries

Year Planted

2021

Height

13.5"

Spread

8.5"

Number Planted

9

Survival

100%

Comments
Very uniform; compact plants with upright habit; produces a large number of single flowers with wide petals that bloom from late spring then sporadically through early fall; novel flower pattern- lime-green tipped flowers with a bright red center; as flower matures color shifts to all red; the unusual flower color has been a people magnet; deer resistant; great for attracting pollinators.

Glandularia canadensis 'Homestead Hot Pink'
rose verbena

Company

Ball Seed Co.

Year Planted

2021

Height

5.5"

Spread

19"

Number Planted

9

Survival

78%

Comments
Low groundcover with a spreading plant habit; lots of flower power- attractive magenta colored flowers that cloak the plants from late spring through early fall; deer resistant; attracts bees, butterflies, and other pollinators; low maintenance.

Heliopsis helianthoides 'Summer Eclipse'
false sunflower

Company

Ball Seed Co.

Year Planted

2021

Height

18"

Spread

5.5"

Number Planted

9

Survival

78%

Comments
Upright habit; daisy-like flowers with a cone-shaped brown eye; bicolor flower ranges from deep orange center edged in light orange- golden yellow to solid orange; blooms from late spring then sporadically through early fall; good for cut flowers; attracts butterflies,bees, and other pollinators.

Heuchera 'Big Top Caramel Apple'
coral bells

Company

Ball Seed Co.

Year Planted

2021

Height

7"

Spread

10.5"

Number Planted

9

Survival

100%

Comments
Large mounds of attractive, big-leafed foliage- new leaves are a reddish color turning to a yellow-caramel color; rabbit resistant; low maintenance.

Heuchera 'Black Forest Cake'
coral bells

Company

Terra Nova Nurseries

Year Planted

2021

Height

4"

Spread

5"

Number Planted

9

Survival

33%

Comments
Mounding habit; dark chocolatey foliage with bright red flowers; very attractive contrast between the bright red flowers and the dark colored foliage; blooms from early spring to early summer; low maintenance.

Heuchera 'Carnival Burgundy Blast'
coral bells

Company

Ball Seed Co.

Year Planted

2021

Height

5.5"

Spread

10"

Number Planted

9

Survival

100%

Comments
Large mounds of attractive, big-leafed burgundy-red colored foliage; rabbit resistant; low maintenance.

Heuchera 'Carnival Cinnamon Stick'
coral bells

Company

Ball Seed Co.

Year Planted

2021

Height

5"

Spread

10"

Number Planted

9

Survival

100%

Comments
Large mounds of attractive, big-leafed foliage; beautiful foliage color that is true to it's name, brings to mind cinnamon red hots; rabbit resistant; low maintenance.

Heuchera 'Ruby Tuesday'
coral bells

Company

Terra Nova Nurseries

Year Planted

2021

Height

4.5"

Spread

9"

Number Planted

9

Survival

78%

Comments
Mounding habit; ruffled foliage is a ruby color; Moderately large and very full; rabbit resistant; low maintenance.

Heuchera 'TNHEUNESI'
Northern Exposure Sienna coral bells

Company

Terra Nova Nurseries

Year Planted

2021

Height

4"

Spread

6.5"

Number Planted

9

Survival

44%

Comments
Small mounds; foliage color when it emerges is yellow with orange along the veins turning to a solid yellow in summer and then when temperatures cool off in the fall the orange color returns to the leaves; foliage burns in our intense heat and light levels- would do better in shade; rabbit resistant; low maintenance.

Kniphofia 'Citron'
Poco red-hot poker

Company

Terra Nova Nurseries

Year Planted

2021

Height

13.5"

Spread

10"

Number Planted

9

Survival

100%

Comments
Upright habit; uniformly compact; plants were loaded this year with citrus-yellow colored flower spikes; blooms from late spring then sporadically through early fall; stunning in mass plantings; rabbit resistant.

Lagerstroemia 'Cherry Delight'
GreatMyrtle crepe myrtle

Company

GardenChoice

Year Planted

2021

Height

12"

Spread

14"

Number Planted

5

Survival

100%

Comments
Compact plants; mounded habit; nice branching; prolific flowering; clusters of attractive deep cherry red colored flowers from late spring then sporadically through early fall; low maintenance.

Lagerstroemia 'Cotton Candy'
GreatMyrtle crepe myrtle

Company

GardenChoice

Year Planted

2021

Height

12.5"

Spread

15.5"

Number Planted

5

Survival

100%

Comments
Compact plants; mounded habit; nice branching; prolific flowering; clusters of attractive light pink colored flowers from late spring then sporadically through early fall; low maintenance.

Lagerstroemia 'G18147'
GreatMyrtle French Vanilla dwarf crepe myrtle

Company

GardenChoice

Year Planted

2021

Height

11"

Spread

14.5"

Number Planted

5

Survival

100%

Comments
Compact plants; mounded habit; nice branching; prolific flowering; clusters of attractive clear white colored flowers from late spring then sporadically through early fall; low maintenance.

Lagerstroemia 'Red Velvet'
GreatMyrtle crepe myrtle

Company

GardenChoice

Year Planted

2021

Height

11"

Spread

13"

Number Planted

5

Survival

100%

Comments
Compact plants; mounded habit; nice branching; the last to bloom in the GreatMyrtle series; clusters of red colored flowers from late spring then sporadically through early fall; minor issue with Japanese beetles; low maintenance.

Leucanthemum 'Mt. Hood'
Shasta daisy

Company

Terra Nova Nurseries

Year Planted

2021

Height

4.5"

Spread

12.5"

Number Planted

9

Survival

44%

Comments
Mounded habit; Large, double flowers that are clear white with a yellow center that bloom from late spring then sporadically through early summer; Extremely floriferous, flowers cover the entire plant; new flowers cover the older spent ones so the plant always has a clean appearance.

Lysimachia alfredii 'Night Light'
moneywort

Company

Ball Seed Co.

Year Planted

2021

Height

6"

Spread

11"

Number Planted

9

Survival

78%

Comments
Low growing spreading groundcover; attractive dark foliage with bright yellow flowers; blooms from late spring then sporadically through early fall; low maintenance; struggles in our bright light and heat- would do better in shade.

Monarda 'Balbeemav'
BeeMine Lavender bee balm

Company

Ball Seed Co.

Year Planted

2021

Height

12.5"

Spread

16"

Number Planted

9

Survival

100%

Comments
Upright habit; loaded with lavender colored flowers; blooms from late spring then sporadically through summer; magnet for bees, butterflies, and other pollinators; deer resistant; rabbit resistant; good resistance to mildew.

Monarda 'Balbeemed'
BeeMine Red bee balm

Company

Ball Seed Co.

Year Planted

2021

Height

11.5"

Spread

15"

Number Planted

9

Survival

100%

Comments
Upright habit; loaded with pinky-red colored flowers; blooms from late spring then sporadically through summer; magnet for bees, butterflies, and other pollinators; good resistance to mildew; deer resistant; rabbit resistant.

Monarda 'Balbeemin'
BeeMine Pink bee balm

Company

Ball Seed Co.

Year Planted

2021

Height

17"

Spread

21.5"

Number Planted

9

Survival

100%

Comments
Upright habit; loaded with deep pink colored flowers; blooms from late spring then sporadically through summer; lost most of it's foliage- not as strong a resistance to powdery mildew as the other two in the Bee Mine series; deer resistant; rabbit resistant; magnet for bees, butterflies, and other pollinators.

Nepeta subsessilis 'Balprelurp'
Prelude Purple short-stalked catmint

Company

Ball Seed Co.

Year Planted

2021

Height

17"

Spread

20"

Number Planted

9

Survival

100%

Comments
Mounding habit; covered in small purple flowers from late spring then sporadically through early fall; attracts butterflies, bees, and other pollinators; pleasant mint fragrance to leaves.

Phlox paniculata 'Balkaposin'
Ka-Pow Soft Pink garden phlox

Company

Ball Seed Co.

Year Planted

2021

Height

9"

Spread

9.5"

Number Planted

9

Survival

100%

Comments
Upright habit; well branched; uniform plants; prolific bloomer; light pink with dark pink eyed flowers are borne by nice sturdy stems; blooms from early summer then sporadically through early fall; low maintenance; attracts butterflies, bees, and other pollinators; deer and rabbit resistant.

Phlox paniculata 'Balsukaco'
Super Ka-Pow Coral garden phlox

Company

Ball Seed Co.

Year Planted

2021

Height

6"

Spread

5"

Number Planted

9

Survival

100%

Comments
Upright habit; well branched; uniform plants; prolific bloomer; coral flowers are held up on sturdy stems; blooms from early summer then sporadically through early fall; low maintenance; attracts butterflies, bees, and other pollinators; deer and rabbit resistant.

Phlox paniculata 'Balsukalu'
Super Ka-Pow Blue garden phlox

Company

Ball Seed Co.

Year Planted

2021

Height

9.5"

Spread

11.5"

Number Planted

9

Survival

100%

Comments
Upright habit; well branched; uniform plants; prolific bloomer; light pink with dark pink eyed flowers are held up on sturdy stems; blooms from early summer then sporadically through early fall; low maintenance; attracts butterflies, bees, and other pollinators; deer and rabbit resistant.

Rudbeckia hirta 'Flame'
Minibeckia black-eyed Susan

Company

GardenChoice

Year Planted

2021

Height

23.5"

Spread

17"

Number Planted

9

Survival

22%

Comments
Mounding, compact habit; strongly upright with good branching; loaded with large, attractive semi-double flowers that are bright yellow with a red eye; blooms from late spring then sporadically through early fall; mass planting is absolutely stunning; great pollinator plants; only 1 plant still alive- we should treat it as an annual in our locale- but so worth it!

Veronica 'TNVEOVB'
Vespers Blue speedwell

Company

Terra Nova Nurseries

Year Planted

2021

Height

2.5"

Spread

7"

Number Planted

9

Survival

100%

Comments
Low growing, well controlled spreading plants; long bloom period-from late spring then sporadically through early summer; attractive deep blue flowers; deer resistant; great for attracting pollinators; low maintenance.