Because switchgrass, Panicum virgatum, is native to almost every state in the U. S. it has a wide variation of growth habits and forms. Shown above are newer forms, from the left, Bad Hair Day, Purple Tears, Blue Fountain, and Apache Rose on Sept 17, 2020 at the Minnesota Landscape Arboretum Grass Collection.
‘New Wave’ is 5 to 5 1/2 feet tall with yellow foliage and ‘Blackhawks’ is closer to 6 feet, with dark red or purple foliage. Both of these new cultivars are more upright, at least at the Minnesota Landscape Arboretum, than other big bluestem cultivars.
Native to Minnesota and much of central U.S., purple lovegrass, Eragrostis spectabolis, is a warm season bunch grass that grows only 12-18 inches in height. Showy with red flowers as seen on July 30 at the Minnesota Landscape Arboretum.
In mid July we see the changes from cool season to warm season grasses; northern lawn grasses have flowered and if not cut, the flowers are turning brown. These flowers are past anthesis or pollen shedding and the stems will begin to senesce or die as they turn brown. Kentucky bluegrass, the European meadow grasses so prevalent in the U.S. such as orchard grass, and brome grass are cool season grasses. ‘Karl Forester’ featherreed grass is a common cool season grass, shown in the left photo below in early July just past flowering, and again in September with brown stems in the center back and extreme right of the right photo.
Warm season grasses are the reverse and are just beginning to come “out of the boot” or stem and are beginning to show their flowers and shed pollen in mid-July. From late July through September warm season grasses are in full flower and at their peak. Big and little bluestem, blue grama, prairie dropseed Indian grass and switchgrass are warm season grasses. Little bluestem Blue HeavenTM is on the right photo in the front, below the maple tree, showing its red fall color in September. Use both cool and warm season grasses in the landscape to take advantage for their diverse growth patterns.
Calamagrostis ‘Overdam’ (left) Avalanche’ (right) and are white striped forms of ‘Karl Forester’ feather reedgrass. Are the new variegated forms different?
‘Lightning Strike’ (left) and ‘Hello Spring’ (right) are new mutations of ‘Karl Forester’. Both ‘Avalanche’ and ‘Lightning Strike’ have leaves with white centers and green margins and are taller, growing 45-55 inches in height. ‘Overdam’ and ‘Hello Spring’ have foliage with green centers and white margins and are shorter, 40-45 inches in height.
‘Lightning Strike’ (left) with white center and ‘Hello Spring’ green center; showing reverse foliage variegation. Watch for all green reversions on any variegated plant; remove any green foliage as this will dominate and crowd out the desirable striped forms.
Full of flowers on June 10, 2020, Eiler’s Fescue is named after Henry Eiler, a nurseryman and botanist from Illinois. I think this is a form of Festuca ovina. Typical of cool season grasses, flowers in June followed by brown seedheads by August, this plant will change through the summer. Only 12 inches tall this was planted in 2019 with 6 plugs. Not sure how long it will live in the clay soil of the Minnesota Landscape Arboretum, but looks great now!
Pictured below are Carex montana and Carex pensylvanica ‘Straw Hat’ blooming on April 30, 2020 at the Minnesota Landscape Arboretum. Carex montana is native to Europe and Russia and has survived one winter in Minnesota. ‘Straw Hat’ is a selection of Penn sedge from Intrinsic Perennials that has many flowers. Both are low growing sedges for shade. Penn sedge has good sun tolerance but can turn brown in late summer with full sun.
Native sedges can begin to grow as soon as the snow leaves Minnesota. Shown here are Carex pedunculata, longstalk sedge, foreground and Carex grisea, wood gray sedge, back left. It’s nice to see the green color early in the spring.