CSU announces top perennial picks from trial garden

By JoAn Bjarko
North Forty News

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Gardeners who have trouble choosing among the hundreds of varieties available at greenhouses and from seed packets can narrow down their choices simply by turning to local experts.

Such guidance is much appreciated with local growing conditions characterized by high altitude, intense solar radiation, drying winds, severe hailstorms, large fluctuations between day and night temperatures and a season-long need for irrigation. With these considerations in mind, professionals select plants best suited to the High Plains and Rocky Mountain Region through the annual flower and herbaceous perennial trials at Colorado State University.

Each year, the annual trial consists of more than 1,000 different cultivars of bedding plants. In addition, the garden has a pansy/cool-season crop overwintering trial, as well as a new two-year perennial trial program designed to test newer cultivars that have been introduced in the past three years or less.

The Annual Trial Flower Garden is located at the intersection of Remington and Lake streets in Fort Collins. The perennial beds are across the street in front of the CSU Center for the Arts. Gardens will be at peak bloom in midsummer, a great time to visit and make personal selections for the following year.

James Klett, CSU professor and Extension landscape horticulture specialist, has provided the following information on the perennial winners of the 2009 trials. We will higlight the annual trials in the June issue.

• Anemone 'Little Princess' (Little Princess Windflower) from Blooms of Bressingham. This compact windflower forms a neat mound and offers exceptional late-season color. Flowers are a delicate pink blended with white and with prominent gold stamens. Perfect for a lightly shaded border or containers. Prefers moist but well-drained sites.
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• Aster 'Vibrant Dome' (Vibrant Dome New England Aster) from Blooms of Bressingham. When in bloom, this plant is covered with vibrant lavender-pink flowers. Deserving of a prominent place in any sunny border, growth habit is round and very uniform when used as a mass display. Mildew and deer resistant, it does best in fertile, well-drained soil.
• Euphorbia 'Bonfire' (Bonfire Spurge) from Blooms of Bressingham. New growth is a mixture of purple, orange, red and chartreuse giving a fiery appearance. Leaves quickly turn maroon with undergrowth dark green. Chartreuse flowers and bracts make an impressive combination with the dark foliage. Flowers are self-cleaning and deadheading was never required. Reliably hardy for this area. Nice fall color as well.
• Geranium 'Blue Sunrise' (Blue Sunrise Cranesbill) from Blooms of Bressingham. New leaves have hints of orange upon emergence but turn a startling chartreuse color. This dynamic foliage is a great contrast for the blue-violet flowers throughout most of the growing season. Plant vigor is impressive and it will need extra space.
• Heuchera 'Blackout' (Blackout Coral Bells) from Center Greenhouse. Impressively black foliage is the main drawing point. Besides the nice dark color it is also very glossy and does not scorch or fade even in full sun. The flowers are ivory colored and prolific but may obscure the foliage. Tolerates variable conditions well. It will even handle the heat better than many other coral bells.
• Hibiscus 'Summer Storm' (Summer Storm Rose Mallow) from Walter's Gardens. This vigorous hibiscus variety has beautiful deep purple foliage as it emerges and eventually all but veins and leaf petioles turn green. Large dark pink flowers with magenta eyes are prevalent for a long period. It is late to emerge in the spring but worth the wait. Does best with plenty of water.
• Pennisetum 'Piglet' (Piglet Fountain Grass) from Gulley Greenhouse. This fountain grass caught people's attention at peak flowering due to small yellow anthers that gave it a golden glow from a distance. Tawny plumes arch above medium green foliage in late summer. Perfect in the foreground of any bed especially when used with other late bloomers. Small enough to be used in containers. Prefers moderate moisture. Deer resistant.
• Pulmonaria 'Gaelic Spring' (Gaelic Spring Lungwort) from Proven Winners. Mounds of lime green dappled leaves emphasize pink flowers that emerge from purple buds. Perfect for shady borders but did surprisingly well in full sun. Very easy to grow.
• Rudbeckia 'Early Bird Gold' (Early Bird Gold Coneflower) from Center Greenhouse. Unlike other black-eyed Susans, this variety is day-length neutral. This allows it to produce its golden, daisy-like flowers earlier in the season, and it will continue to bloom longer than other Rudbeckias. Flowering was prolific. Plants had excellent winter survival after one winter and were very uniform. Benefits from deadheading. Moderate to low water needs.
• Salvia 'Pink Friesland' (Pink Friesland Meadow Sage) from Center Greenhouse. This compact produces a profusion of reddish pink flower spikes throughout most of the season, especially if spent blooms are removed. Attracts bees, butterflies and hummingbirds. Excellent for any sunny border or container. Should be drought tolerant.
• Saxifraga x arendsii 'Touran Scarlet' (Touran Scarlet Rockfoil) from Gulley Greenhouse. This early bloomer produces red blooms above compact, evergreen foliage. Plants are attractive even without flowers. It is so beautiful with a unique texture that people want to touch it. Perfect for lightly shaded rock gardens but did great in full sun. Average to lower water needs. Supposedly rabbit and deer resistant.
• Silene 'Rolly's Favorite' (Rolly's Favorite Rose Campion) from Skagit Gardens. Soft pink blooms with white centers form atop upright stems graced with oval, dark green leaves. Flowers are prolific and plants have a long bloom time. Requires deadheading for best appearance and some secondary blooming. Requires well-drained soil.
• Veronica spicata 'Tickled Pink' (Tickled Pink Spike Speedwell) from Eason Horticultural Resources. Produces large showy inflorescences of pink flowers. Selected for longer-lasting flowers. Uniform flowering and growth habit made a very impressive overall appearance.

The trial garden is open daily to the public, free of charge. The perennial trials are displayed year-round. Pansies are planted in the fall and are on display through early spring. The entire garden is planted with annuals from late May through October.

Visitors are encouraged to take note of the new varieties being grown and to observe and study the different growth habits, tolerances and visual characteristics of the many different varieties that have been put on display.