“Top Performer” Perennials from the 2018 CSU Perennial Tial

Posted by Dr. Jim Klett, Department of Horticulture and Landscape Architecture

The results are in and we are excited to announce the 2018 "Top Performer" Perennials! Winners of the "Top Performer" award are selected by a different process than the "Best Of" Annual winners. Since individual perennials often peak at different times of the year, evaluators meet and review photos taken every two weeks during the growing season for the entire trial period of two winters and three growing seasons. Data tabulated by the student coordinator throughout the season is also taken into consideration during the process. The evaluators are members from the Perennial Trial Garden sub-committee which is made up of professionals from the local Green Industry as well as staff from Colorado State University. A perennial entry is only considered for the "Top Performer" award if it has maintained superior performance in the ground for two winters and three growing seasons.

Geum ‘RUSTICO™ Orange’ from Terra Nova^® Nurseries

(Geum x ‘TNGEURO’^PP28238)

Flowers were a beautiful bright orange and very prolific but the foliage was equally impressive if not more so and some evaluators commented the plant “looked so good that it didn’t even need the flowers”.    Plants had a great dark green foliage that kept a fresh look all through the season and made a good contrast for the colorful blooms.  The growth habit was very controlled and had a very uniform appearance.  It would make a great choice for mass plantings.

 

 

 

Phlox Flame® New Improved Purple from Dummen Orange^®

(Phlox paniculata Flame^® New Improved Purple)

Abundant purple flowers made a solid canopy of color at peak bloom and also rated higher than other phlox for an impressively long bloom period.  Plants had a very uniform growth habit with dark green foliage.  A small splash of white at the base of each petal added a bit of “sparkle” to each flower as it matured.  Blooms also were noted to have an attractive color even as they faded late in season.  Plants had superior resistance to powdery mildew.

 

 

KISMET™ Raspberry Coneflower from Terra Nova^® Nurseries

(Echinacea 'TNECHKR'^PP28768)

Prolific flowers formed a solid canopy of blooms over the plants and even had an attractive rustic look as it faded from peak bloom.  Dark green foliage kept the plant attractive even at times when the flowers were not present.  Plants had a very uniform growth habit and good branching.  The KISMET™ series also features colors of orange, red and yellow.

 

Gaillardia ‘SpinTop Yellow Touch’ from Dummen Orange^®
(Gaillardia aristata ‘SpinTop Yellow Touch)
Plants were unique with a relatively small, compact mounded growth habit but packed a lot of flower power on the top of each one.  Flowers were very showy and predominately red but had an edge of yellow around the tip of each blossom.  Plants had attractive green foliage that complemented the bloom color.  Cold hardiness was also very impressive as the survival rate was very good for a Gaillardia.  Additional entries in the ‘SpinTop’ series seemed to have superior cold hardiness as well.

 

 

Delosperma ‘Alan’s Apricot’ from Plant Select

(Delosperma ‘Alan’s Apricot’^PPAF)

Flowers made this a standout for both the unique color and continual blooming through the season.  At peak bloom plants are just a carpet of Apricot colored flowers. Plants are very uniform, have great vigor and have better cold hardiness than most Delosperma .  Good for low water plantings but will also tolerate extra water in areas that often kills other Delosperma.  This is a great low maintenance plant.

 

Colorado State University Announces 2017 “Top Performing Perennials”

Posted by James E. Klett, 

Department of Horticulture and Landscape Architecture, Colorado State University

The following six perennials were recently selected by the Perennial Trial Garden sub-committee as being superior after 3 years of growth and winters.  Plan to utilize these in your designs and home gardens in 2018. I think you will be happy with the results.

Kahori® Border Pink from Bartels

(Dianthus ‘Kahori’)

Noted as an impressive advancement in breeding, evaluators described this as the new standard for Dianthus.  The vibrant pink flowers cover the plants at peak bloom and create a mat of stunning color.  This entry is superior for an extremely long period of bloom and exceptional uniformity.  It has proven to be reliably winter hardy and would look great in a rock garden or crevice garden.  It looks great in ground beds and would make a beautiful border, but is a great choice to use in containers since it is always in bloom.  This selection remains very compact and has great heat tolerance during the peak of summer temperatures.  It was very attractive even during its first year in the garden and has only gotten better each year since it was planted.

Winterbells® Helleborus from Hilverdakooij

(Helleborus Interspecific 'JWLS')

This winner was selected in part for its unique ability to bloom over the entire spring and summer.  It adds a touch of elegance to the garden with delicate nodding bells, glossy dark green foliage and a very attractive dense, compact growth habit.  Narrow, graceful foliage can be evergreen if planted in a protected location and is relatively low maintenance.  The subtly beautiful bell shaped flowers provide a long season of interest as they emerge a dusty pink, becoming pale yellow, white, and then light green by summer.  Besides making a great groundcover, the flowers are useful for cut flower production throughout the year.

 

 PHENOMENAL™ Lavender from Cultivaris

(Lavandula x intermedia ‘Niko’^PP24193)

The abundant, tall graceful flower stalks are held high above the foliage for maximum display.  Besides being very uniform, all plants had excellent cold hardiness.  It was noted that they would do best if grown on the drier side to avoid lodging of the flower stalks.  Pollinators are very attracted to this plant and it has a high oil content that makes is very attractive to commercial production as well as providing the classic lavender fragrance to the garden.

 

Flame® Blue Phlox from Bartels

(Phlox paniculata Flame^® Blue)

Abundant blue and white flowers are held upright on sturdy stems that never lodged despite overhead irrigation used in the garden.  Flower color is a subtle blue that is strongest in early summer and again late in the season as the temperature cools.  It was a relatively early bloomer starting in mid-July and could continue through October if deadheaded.  Self-branching plants had a very full and uniform growth habit as well as superior resistance to powdery mildew.

 

 

Ronica™ Dark Pink Veronica from Danziger

(Veronica Ronica™ Dark Pink)

Big, fat and sassy flower spikes put on an eye-catching show of vibrant pink flowers.  Plants keep a very formal appearance with great uniformity and glossy emerald green foliage that really sets off the pink flowers.  Bloom period was very long especially if deadheaded.  Had superior resistance to powdery mildew compared to other entries growing in the trial.  Growth habit was very full and dense.

 

Class of 2016 - “Too Good to Wait” Award

The Perennial Trial Garden Sub-committee likes to award the ‘Top Performer’ designation to superior plants that have been in the ground 2 winters and 3 growing seasons. This category is to acknowledge an upcoming plant that has been in the ground one winter and two growing seasons and shows excellent performance thus far in the trial. The following plant impressed the Perennial Trial Garden Sub-committee so much that they designated the category name: “Too Good to Wait Performer”.

 

KISMET™ Intense Orange Coneflower from Terra Nova Nurseries

(Echinacea 'TNECHKIO'^PPAF)

The sheer mass of vibrant flowers draws people all the way from across the street.  Prolific flowers form a solid canopy of blooms over the plants which makes this variety a great choice for the home gardener or landscaper looking for a showstopper.  The intense orange color almost seems to glow at its peak.  Flower color fades to an attractive shade of pale yellow to maintain a long season of bloom.  Foliage is also very unique and attractive early in the season.  Plants have a very uniform growth habit and good branching.  The KISMET™ series also features colors of raspberry, red and yellow.

Helleborus for Colorado

Posted by Jim Klett – CSU Professor and Extension Landscape Horticulturist

In our 2 winter, 3 growing season perennial trials at Colorado State University we have been trialing numerous species of Helleborus for five years.  I have been extremely impressed with their performance and hardiness and adaptability in our trials.  The common name is lenten rose and they generally grow 15-18 inches in size and 15-20 inches or more in width.  Plants are evergreen but sometimes the foliage can get battered by late winter.  If this happens, prune off the dead leaves at this time to make room for new growth and flowering.  Some gardeners mow the old foliage off of large plantings of the lenten rose for complete renewal.

The flowers start blooming in mid to late February with rose or cream speckled flowers and bloom for a long time.  The sepals are attractive for a long time after blooming.  Helleborus can reseed heavily by the hundreds under certain conditions.  Usually the seedlings are located at the base of parent plant and can flower in about the third spring.  This can create a nice effect in a natural setting.

Helleborus generally prefer a more moist organic well-draining alkaline soil.  We have them planted in partial to full shade and they have performed excellent.  They will tolerate some drier conditions in the summer.  Plants are long lived and once established, division is seldom.

We have planted many varieties of the Gold Collection® series from Skagit Gardens.  Two that appear outstanding include:  Maestro Hellebore (Helleborus x  ballardiae ‘COSEH890’).  Plant has shiny dark green foliage appearing almost black at times toward the end of the season.  Flower petals emerge a deep pink with white and mature to a creamy white with shades of dusty rose on the backside.  Flowers covered the plant from side to side and was very prolific.  Plants were compact and with good vigor.

Maestro Hellebore in mid-March

Maestro Hellebore in mid-March

Flower fades to a dusty rose color in mid-April 

Merlin Hellebore (Helleborus x ballardiae ‘COSEH810^{USPP #22350}) flowers on this Hellebore emerged with pink color that is brighter than most and then matured to shades of dusty rose.  Blooms were held above foliage creating an impressive display.  Plants were more compact with long lasting dark green foliage and very low maintenance.

Merlin Hellebore with a deep pink color in mid-March

Merlin Hellebore flower color matures to a dusty rose in mid-April

Merlin Hellebore with dense, compact growth habit in mid-April

Hellebores are a great perennial for late winter early spring flower color that are evergreen and low maintenance.  If you do not have some in your garden try some and enjoy the early spring flower color and nice green foliage throughout the rest of the year.

2014 “Top Performer” Perennials from the CSU Trial Gardens

Posted by: Jim Klett, Extension Specialist

The results of the 2014 “Top Performer” perennial trials have been chosen.  A perennial entry is only considered for the “Top Performer” award if it has been in the ground for two winters and three growing seasons although the “Too Good to Wait” award is used for an entry the evaluation committee is confident is superior even after one winter and two growing seasons. For a full list, visit: www.flowertrials.colostate.edu 

The 2014 “Top Performers” include:

Blue Boa Agastache from Terra Nova® Nurseries

(Agastache x hybrida 'Blue Boa'^PP24050)

 Non-stop flower power resulted in a season long splash of bright lavender color that covered the plant in blooms from top to bottom.  Excellent vigor and a relatively large growth habit would make this a good choice for the back of a perennial border that needs color.  Besides all the beauty, this plant is also recommended for its drought tolerance and ability to attract bees and butterflies.  Planted in 2012.

Leilani Coneflower from Terra Nova® Nurseries

(Echinacea spp. 'Lelani' ^PP23526)

Tall, vigorous plants "wowed!" visitors with the prolific display of "warm, buttery yellow" flowers.  Blooming occurred over a long period and the plants maintained superior controlled vigor for good uniformity and overall appearance.  Planted in 2012.

Profusion Coneflower from Eason Horticultural Resources

(Echinacea purpurea 'Profusion')

Flowers had a unique appearance and overall shape due to many petals with a nice shape and a large, dark center.  The dark stems also complemented the flower petals and dark center.  Plants were compact but flowering was very profuse.  The light lavender petals also faded nicely into a "antique" lavender color that was also very attractive and extended the bloom time.  Planted in 2012.

Georgia Plum Coral Bells from Terra Nova® Nurseries

(Heuchera x hybrida 'Georgia Plum'^PP24507)

Plum colored foliage was impressive all season and did not show any signs of fading.  Besides the plum color, foliage also had a nice silver sheen for good color impact throughout the growing season.  Plants were very uniform and had excellent growth habit.  Predominantly grown for the foliage, the light pink/plum flowers were few but still attractive.  Planted in 2012.

Midnight Marvel Hibiscus from Walters Gardens/ Proven Winners®

(Hibiscus x hybrida 'Midnight Marvel'^PP24079)

The flowers and foliage made a spectacular combination.   Dark bronze foliage made a perfect backdrop to the beautiful red flowers.   Many flowers came into bloom together and created a good visual impact.  Plants were vigorous but maintained a nice size without getting too large.  Planted in 2012.

 

 "Too Good to Wait" Winners

 Electric Avenue Coreopsis from Creek Hill/Eason

(Coreopsis verticillata 'Mayo Clinic Flower of Hope'^PPAF or 'Electric Avenue')

Bright yellow flowers were very showy and flowering was solid all season.  Plants were vigorous, uniform and maintained good stature from spring to fall.  Fine textured foliage and a nice flower shape contributed to a very pleasing overall affect.  This is good plant for attracting bees.   

  

Beyond Blue Fescue from Skagit Gardens

(Festuca glauca 'Casca11' ^{PP #23307} )

This fescue is considered to have the best "blue" color out there!  Plants  maintain a nice "ball" shape and do not open in the middle.  Flower stems fade and disappear amongst the foliage for a superior appearance.  This is an improved variety over older ones for foliage color.

Sunrosa™ Red Rose from Suntory® Flowers

(Rosa x hybrid Sunrosa™ Red)

Constant red flowers and impressive growth habit make this plant attractive all season.  Glossy dark green foliage had no signs of chlorosis or disease.  Red flowers bloomed steadily from mid-June through October.  Small foliage and a dwarf compact growth habit make this a good choice for the smaller or mid-size landscapes. 

Perennial ‘Top Performers’: Information from the CSU Two-Year Perennial Trial

By: Jim Klett, Professor and Extension Landscape Horticulturist, Department of Horticulture and L.A., Colorado State University

Now since it is officially spring, industry professionals and gardeners are thinking of growing and planting perennials. I hope you will consider these ‘Top Performers’ from the CSU Trials. These perennials were planted in 2010 and researched for 3 growing seasons and 2 winter periods.  For more information on the perennial trials, visit our website. 



Buzz™ Butterfly Bush

Buddleia davidii ‘buzz™’ ^PPAF series, (Buzz™ Butterfly Bush Series) – This entire series was noted for excellent flower production and dense growth. Range of colors in series was Blue Violet, Ivory, Pink Purple, Violet and Magenta. These more compact Butterfly Bushes work well as a mixed border plant.

Gold Collection® Lenten Rose

Helleborus x ballardiae ‘Gold Collection®’ series, (Gold Collection® Lenten Rose series) – The plants were noted for early blooms (March) with flowers facing upright and dark glossy green foliage year round. These plants make a great groundcover for a shady area. Flower color varies from a pink blush with yellow interior to pink blush on chartreuse petals.



Fireball Bee Balm

Monarda ‘Fireball’ ^{PP #14,235}, (Fireball Bee Balm) – Plants are prolific bloomers in July with wine colored blooms on sturdy stems with no lodging, even with overhead irrigation. They have superior mildew resistance and great for the back of perennial border.

Phlox paniculata ‘Classic Cassis’ ^PPAF, (Classic Cassis Perennial Phlox) – Plant has a long bloom time with big bold flowers. Flowers are a bright pink color with hints of mauve which start in June and continue well into August. Plants have good clean green foliage throughout the season.



Pina Colada Perennial Phlox

Phlox paniculata ‘Pina Colada’ ^PP#19968, (Pina Colada Perennial Phlox) – Pure white flowers are impressive against the dark green foliage from June into September. Growth habit is compact and spent flowers drop off the flower panicles that give plant a clean look throughout the season.

These five perennials are a must for producers, retailers and gardeners for the 2013 growing season.