Superior Herbacious Perennials
for the High Plains
Colorado State University maintains perennial trial gardens at the W. D. Holley Plant
Environmental Research Center (PERC) in Fort Collins, Colorado. The main objective of
these gardens is to determine which herbacious perennials are best suited for growing in
the Rocky Mountain area.
Growth, cultural, and landscape characteristics of these plants have been observed
annually, resulting in a database for evaluating their suitability for use in High Plains
The following are some of the perennials that have shown to be superior performers for
the High Plains:
(click on thumbnails for larger pictures)
||Astrantia major 'Margery Fish' - Margery
This particular variety of masterwort reaches its peak bloom in
August (shown here in July). With its extra long collar of pink bracts surrounding the
petals, it makes a wonderful cut flower for bouquets or drying. Reaching about 2 to 3 feet
in height, Margery Fish does best in full sun or part shade and prefers well-drained
||Calamagrostis x acutiflora 'Overdam' -
Variegated Feather Reed Grass
This is an erect, clumping cool season grass with
variegated medium-green foliage with cream stripes. Variegated Feather Reed Grass grows
vertically and makes a natural screen. The flowers are held erect in slender spikes, then
tighten into narrow seed heads. This cultivar is non-invasive.
||Sidalcea 'Party Girl' - Prairie Mallow or
Checker Mallow or False Mallow
This plant is handsome in leaf or in flower. The
leaves are shiny and either rounded or palmately lobed. The erect flowering stems reach
four feet high and flowers are borne in terminal racemes and resemble miniature hollyhock
flowers. 'Party Girl' has silky pink petals and a white central eye.
||Lavatera thuringiaca -Tree Mallow
is a shrubby two to four foot tall plant, closely related to hollyhocks and mallow. The
saucer-shaped pink blooms have five showy petals. They are borne in the leaf axils and on
loose, terminal racemes. This plant is easy to grow and prefers full sun and well-drained
||Miscanthus floridulus 'Giganteus' - Giant
Chinese Silver Grass
This species is certainly the giant of the Miscanthus.
It grows 12 to 15 feet high. Excellent as a screen or background plant for smaller
grasses. Flower plume develops in mid-September and provides a super winter effect. Stems
will persist until spring or later unless cut down.
||Acanthus longifolius - Bear's Breeches
unusual, statuesque plant, Bear's Breeches may grow 3 feet by 3 feet. Leaves are deep
green and lobed, with deep sinuses. Flower stems appear abouve the leaves and bear purple
and white flowers, surrounded by sharp, spiny bracts - a truly unique bloom. These
plants require sun or part shade and should be placed in an area of the garden less prone
to drying. Flower buds are less hardy than the leaves and after a particularly cold
winter, leaves may appear but no blooms. They are worth the risk!
||Coreopsis verticillata - Threadleaf
Threadleaf Coreopsis is covered by golden-yellow daisy-like flowers
midsummer. These low maintenance plants perform best in sunny, well-drained sites of low
to moderate fertility. Flower are good for cutting and the plant is drought
||Heliopsis helianthoides var. scabra
'Incomparabilis' - False Sunflower
Its name translates literally as
"sun-like" but Heliopsis is smaller, shrubbier and ealier to bloom than true
sunflowers. "Scabra" means rough and refers to the sand-papery feel of the stems
and leaves. False Sunflower requires full sun and good drainage and will bloom from
mid-summer into early fall. It is a great backbone plant for the border and the blooms
make excellent cut flowers.
||Lysimachia cilata purpurea - Purple Fringed
This is definitely one of the more stunning loosestrfes. It has
purple foliage offset by bright yellow flowers.
||Eupatorium maculatum - Joe-Pye Weed
striking plant has erect, pink-spotted stems and whorl-toothed leaves. The pikish-purple
flowers, in late summer, are held in large terminal clusters. The plant matures to 4 to 6
feet in height and 1 to 2 feet wide.
||Phlomis russeliana - Sticky
This member of the mint family has woolly medium-green leaves and square stems with whorls
of pale yellow, hooded flowers. Attractive seed heads make this a good winter-interest
plant. Sticky Jerusalem Sage prefers full sun and does well in poor soils. It makes an
escellent cut or dried flower.
||Prunella grandiflora - Large
Large Selfheal is a member of the mint family. It spreads into an excellent ground cover
by creeping stems. The purple flowers are two-lipped and held in whorled spikes and
attract bees and other beneficial insects. Prefers full sun to part shade and is not
||Pulmonaria spp. - Bethlehem
This early spring bloomer is a clump forming perennial known for its' spotted or mottled
foliage. The funnel-shaped flowers appear in nodding clusters. Lungwort can tolerate
variable habitats including dry shade. There are several cultivars available:
P. saccharata 'Mrs. Moon': pink buds open to blue flowers that
mature to lilac
P. saccharata 'Roy Davidson': sky blue flowers that fade to
P. officinalis 'Sissinghurst White': pale pink buds open to
pure white flowers
Photos: Judy Sedbrook
Information courtesy of Dr. James Klett, principle investigator, and Vale Skiff,
Curator, PERC Perennial garden.
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