Colorado Nursery & Greenhouse Association members Diana Reavis and Ross Shrigley perused plant lists to pick out a few outstanding choices for Colorado and New Mexico. Reavis of Eason Horticultural Resources was assigned the task of selecting from past Perennial Plants of the Year® (PPOY) from the Perennial Plant Association. Shrigley of Plant Select® was tasked with making his selections from his nonprofit’s recommendation lists. These 12 plants are suited to our states’ USDA Plant Hardiness Zones and offer a variety of colors for landscapes.
Ornamental allium (Allium ‘Millenium’)
Summer allium have been used extensively in the Midwest and Eastern regions for years, but Millenium (PPOY 2018, CSU perennial trial top pick) is particularly outstanding in our region for its highly ornamental masses of rose-purple blooms that start late June and go through the fall. The shiny green foliage has a tidy habit, unlike other allium. Millenium is pest and disease free, deer resistant, very adaptable to our soils, and a bee and butterfly magnet!
Origin: Mark McDonough
Propagation: division
Zones: 3 or 4-9
Height: 10”-15” reaching 18” with flowers
Use: as a middle of the border perennial, cut-flower garden, or large landscape sweeps
Availability: usually readily available; purchase as large plugs, bareroot or finished
Beardtongue ‘Husker Red’ (Penstemon digitalis ‘Husker Red’)
Beardtongue ‘Husker Red’ (PPOY 1996) was selected for its rich bronze-red foliage that contrasts with the abundant blush white flowers on 20 or more stems. Its upright airy structure adds an architectural presence in the garden. Reliably tough and hardy from the steppes to the slopes along the Rocky Mountains.
Origin: Dr. Dale Lindgren of the University of Nebraska
Propagation: best by division or stem cuttings; can be by seed, but must cull out green seedlings to maintain the integrity of the true selection
Zones: 3-8
Height/width: 30”/15”
Uses: in masses in the back of a perennial border or as a specimen
Availability: usually easy to find as plugs, bareroot, seeds, or finished
CLEAR CREEK® golden yellowhorn (Xanthoceras sorbifolium ‘Psgan’)
Clear Creek® golden yellowhorn makes a beautiful multistem ornamental tree with clusters of white flowers that can exhibit yellow and strawberry red centers in April to May. Glossy green pinnately compound leaves persist all summer.
Origin: Plant Select via Green Acres Nursery
Propagation: seed or root cuttings
Zones: 5-8
Height/width: 18’-22’/10’-15’
Uses: ornamental tree or large open-form shrub
Availability: low due to a large taproot, which makes it challenging to grow in a pot or transplant from a tree field
CORAL CANYON® twinspur (Diascia integerrima ‘P009S’)
Coral Canyon twinspur is a very heat-tolerant, water-smart plant with coral-pink oval flowers that bloom from June to October.
Origin: Plant Select via Panayoti Kelaidis
Propagation: vegetative cuttings or division
Zones: 4b-8
Height/width: 12”-18”/10”-16”
Uses: perennial gardens, rock gardens and protected patio containers
Availability: low to moderate depending on the region
Golden storksbill (Erodium chrysanthemum)
Golden storksbill is a wonderful, low-maintenance, water-wise plant that can be planted just about anywhere in a garden or landscape. The one-inch soft pale yellow flowers bloom from May to October above a mound of lacey textured foliage that offers elegant fall color.
Origin: Plant Select via Denver Botanic Gardens
Propagation: vegetative cuttings, divisions
Zones: 4-9
Height/width: 8”-10”/10”-25”
Uses: perennial gardens, rock gardens or to soften shrub beds
Availability: low to moderate depending on the region
Lenten Rose (Helleborus x hybridus)
The extremely adaptable and deer-resistant hellebores (PPOY 2005, CSU perennial trials top pick) were once underused in our region, but are gaining in popularity. These evergreen perennials have long-lasting, nodding blooms in a wide range of colors, from white through the deepest purples and reds. The foliage makes for great dry (not xeric) shade groundcover and the bracts of the flowers remain for months.
Origin: many breeders and named varieties
Propagation: seed or tissue culture
Zones: 4-9 (perhaps 3 with snow cover)
Height/width: 18”-24”/24-30”
Uses: ground cover in the shade, in masses under trees in more fertile soil
Availability: much easier to find in recent years; production is long, so order early as larger plugs or finished plants
Moonbeam coreopsis (Coreopsis ‘Moonbeam’ Tickseed)
Moonbeam (PPOY 1992) is reliably hardy – an oldie but a goodie. It is highly tolerant of the Rocky Mountain region soils and precipitation levels. Creamy yellow daisy-like flowers borne atop thread-like foliage in such profusion as to cover the plant. Blooms throughout summer and into fall.
Origin: unknown, though thought to be an interspecific hybrid of verticillata through either natural or humanmade cross
Propagation: division or vegetative cuttings
Zones: 4-8 (sometimes Zone 3 with adequate snow cover)
Height & width: 18”-24”
Use: good in perennial borders or in landscape sweeps contrasting with bold foliage of other perennials and woody plants
Availability: not usually an issue; purchase as plugs, liners, finished, or bareroot
Moroccan pincushion flower (Pterocephalus depressus)
The Moroccan pincushion flower is one of the most intriguing Plant Select selections. It has beautiful, textured, evergreen greyish leaves and pincushion-like, dusty-rose-colored flowers that bloom in June and July with attractive silvery seed heads.
Origin: Plant Select via Denver Botanic Gardens
Propagation: vegetative cuttings or division
Zones: 4-8
Height 3″ Width 10-15″
Uses: groundcover, rock garden, border plant for pathways and flagstone patios
Availability: moderate, propagation takes longer than other groundcovers
Panchito manzanita (Arctostaphylos x coloradensis ‘Panchito’)
Panchito Manzanita embodies a mountainous landscape feel for the plains of the Front Range. Tiny, waxy, white, urn-shaped flowers are very appealing and bloom from late February to April.
Origin: Plant Select via Betsy Baldwin
Propagation: hardwood cuttings
Zones: 4b-8
Height/width: 10”-24”/36”-60”
Uses: shrub beds or larger rock gardens
Availability: wide, since Calif. and Ore. growers have begun to propagate it successfully
PLATINUM® sage (Salvia daghestanica)
PLATINUM® sage is a knockout beauty in the sunny, dry garden. The deep blue flowers contrast with an electric intensity against silver foliage, which blooms from late May to July.
Origin: Plant Select via Denver Botanic Gardens
Propagation: vegetative cuttings, divisions or seed
Zones: 5-10
Height 8”-12”/12”-18”
Uses: groundcover uses, pathway edges and rock gardens
Availability: moderate
Russian sage (Perovskia atriplicifolia)
Many superior cultivars have emerged in the years since 1995 when Russian sage was the PPOY, all with the same great attributes for use in the Rocky Mountain region. Silver stems with toothed sage-scented grayish foliage are the undercarriage for small light lavender flowers arranged in whorls along the stems. This plant is very well suited to the region for its drought tolerance, hardiness and ease of growing.
Origin: The common variety in the U.S. is a hybrid between P. atriplicifolia and P. abrotanoides.
Propagation: seed, vegetative cuttings or division
Zones: 3-8
Height & width: 48”
Use: treat as a perennial sub-shrub in the landscape or back of border.
Availability: generally easy to find and many cultivars to choose from, as plugs, liners, finished plants, or bareroot
Little Bluestem (Schizachryrium scoparium ‘The Blues’)
Little Bluestem (PPOY 2022) is a steppe region native, well adapted to our poor soils and dry conditions. ‘The Blues’ is a particularly nice cultivar that has a nice upright habit along with lovely, blue-gray foliage that turns purple in the fall, remaining statuesque against a backdrop of snow. Little Bluestem also provides seeds for the birds through the seasons.
Origin: selected at Mt. Cuba research center
Propagation: division for cultivars or seed for straight species
Zones: 3-8
Height/width: 24”-36”/15”-18”
Uses: great in the mixed xeric garden or in landscape sweeps
Availability: can be tight, order early as large plugs, bareroot or finished plants
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