The University of Minnesota conducted a six-year (1987-1993) winter hardiness study of 165 ornamental grasses in zone 4a (minimum annual temperatures -20 to -30 degrees F).   This study is important because 95% of the United States is at or above this USDA hardiness zone!

The listing below of the results of the study are published with permission from the University of Minnesota.  Copies of this very informative booklet, Ornamental Grasses for Cold Climates, North Central Regional Extension Publication 573, can be obtained by contacting one of the following:

The study reported it's findings in three categories:

Recommended for Cold Climates Including USDA Zone 4

Marginally Hardy in USDA Zone 4

Not Recommended as Perennials for USDA Zone 4a

Recommended for Cold Climates Including USDA Zone 4a

• Acorus calamus, sweet flag
  
• Acorus calamus 'Variegatus', variegated sweet flag
  
• Alopecurus pratensis 'Aureus', yellow foxtail
  
• Arrhenatherum elatius 'Variegatum', bulbous oatgrass
  
• Bouteloua curtipendula, side oats gramma
  
• Calamagrostis x acutiflora 'Karl Foerster', Feather reedgrass
  
• Calamagrostis x acutiflora 'Stricta', Feather reedgrass (syn. 'K F')
  
• Calamagrostis brachytricha, fall blooming reedgrass
  
• Carex digitata, finger sedge
  
• Carex flaca, blue sedge
  
• Carex flava, yellow sedge
  
• Carex grayi, Grays sedge
  
• Carex montana, mountain sedge
  
• Carex muskingumensis, palm sedge
  
• Carex nigra, black flowering sedge
  
• Carex speciosa 'Velebit Humilis', velvet sedge
  
• Carex umbrosa, umbrosa sedge
  
• Deschampsia caespitosa, tufted hairgrass
  
• Deschampsia caespitosa 'Bronzeschleier', bronze veil hairgrass
  
• Deschampsia caespitosa 'Fairy's Joke', fairy's hoke hairgrass
  
• Deschampsia caespitosa 'Goldgehaenge', gold pendant hairgrass
  
• Deschampsia caespitosa 'Scottland', Scotland hairgrass
  
• Festuca amethystina 'Bronzeglanz', bronzeluster fescue
  
• Festuca amethystina 'Klose', klose fescue
  
• Festuca amethystina 'Superba', supurba fescue
  
• Festuca cinerea 'Blaufink', blue finch fescue
  
• Festuca cinerea 'Blauglut', blue ember fescue
  
• Festuca cinerea 'Blausilber', blue silver fescue
  
• Festuca cinerea 'Daeumling', tom thumb fescue
  
• Festuca cinerea 'Elijah Blue', blue fescue
  
• Festuca cinerea 'Fruehlingsblau', spring blue fescue
  
• Festuca cinerea 'Harz', harz blue fescue
  
• Festuca cinerea 'Meerblau', ocean blue fescue
  
• Festuca cinerea 'Sea Urchin', sea urchin blue fescue
  
• Festuca cinerea 'Solling', solling blue fescue
  
• Festuca cinerea 'Superba', supurba blue fescue
  
• Festuca muelleri, Muellers fescue
  
• Festuca tenuifolia, fine-leaved fescue
  
• Hakonechloa macra, hakonegrass
  
• Helictotrichon sempervirens, blue oatgrass
  
• Hystrix patula, bottlebrush
  
• Juncus effusus, common rush
  
• Koeleria brevia, blue hairgrass
  
• Leymus arenarius, blue lymegrass (syn. Elymus arenarius)
  
• Elymus arenarius, blue lymegrass (syn. Leymus arenarius)
  
• Leymus racemosus, giant blue rye (syn. Elymus racemosus)
  
• Elymus racemosus, giant blue rye (syn. Leymus racemosus)
  
• Luzula sylvatica, greater woodrush
  
• Miscanthus floridulus, giant miscanthus
  
• Miscanthus oligostachyus, small Japanese silvergrass
  
• Miscanthus sacchariflorus, Chinese silvergrass
  
• Miscanthus sinensis 'Purpurascens', red flam miscanthus
  
• Miscanthus sinensis 'Silberfedher', silverfeather miscanthus
  
• Molinia caerulea 'Heidebraut', heather bride moorrass
  
• Molinia caerulea 'Moorhexe', moorwitch moorgrass
  
• Molinia caerulea ssp. arundinacea, tall moorgrass
  
• Molinia caerulea ssp. arundinacea 'Bergfreund', mountain friend tall moorgrass
  
• Molinia caerulea ssp. arundinacea 'Skyracer', skyracer tall moorgrass
  
• Molinia caerulea ssp. arundinacea 'Staefa', stafa tall moorgrass
  
• Molinia caerulea ssp. arundinacea 'Transparent', transparent tall moorgrass
  
• Molinia caerulea ssp. arundinacea 'Windspiel', windplay tall moorgrass
  
• Panicum clandestinum, deerstongue grass
  
• Panicum virgatum, switchgrass
  
• Panicum virgatum 'Haense Herms', red switchgrass
  
• Panicum virgatum 'Rehbraun', red-brown switchgrass
  
• Panicum virgatum 'Rotstrahlbusch', red-rays switchgrass
  
• Panicum virgatum 'Squaw', swuaw switchgrass
  
• Panicum virgatum 'Strictum', tall switchgrass
  
• Panicum virgatum 'Warrior', warrior switchgrass
  
• Pennisetum flaccidum, meadow pennisetum
  
• Pennisetum incomptum, meadow pennisetum
  
• Phalaris arundinacea 'Picta', ribbongrass
  
• Phalaris arundinacea var. luteo-picta, yellow ribbongrass
  
• Phararis arundinacea 'Feseys Form', Feeseys form ribbongrass
  
• Schizachyrium scoparium, little bluestem
  
• Andropogon scoparius, little bluestem
  
• Sesleria caerulea, blue moorrass
  
• Sesleria heufeliana, green moorgrass
  
• Sesleria nitida, gray moorgrass
  
• Sorghastrum nutans, Indian grass
  
• Spartina pectinata, cordgrass
  
• Spartina pectinata 'Aureo-Marginata', variegated cordgrass
  
• Spodiopogon sibericus, silver spikegrass
  
• Sporobolus heterolepsis, prairie dropseed
  
• Stripa extremorientalis, eastern feathergrass
  
• Themeda triandra 'Japonica', Japanese themeda

• Carex sylvatica, forest sedge
  
• Carex x "The Beatles', mop-head sedge
  
• Festuca amethystina 'April Green', April green fescue
  
• Festuca cinerea 'Silberreiher', silver heron fescue
  
• Festuca mairei, atlas fescue
  
• Festuca pallens, pallens fescue
  
• Festuca pseudeskia, Sierra Nevada fescue
  
• Festuca vallesiaca 'Glaucantha', wallis fescue
  
• Koeleria glauca, blue June grass
  
• Luzula purpurea, purple woodrush
  
• Luzula sylatica 'Hohe Tatra', high tatra mountain rush
  
• Miscanthus sinensis, Japanese silvergrass
  
• Miscanthus sinensis 'Autumn Light', autumn light miscanthus
  
• Miscanthus sinensis 'Condensatus', purple blooming Japanese silvergrass
  
• Miscanthus sinensis 'Gracillimus', maidengrass
  
• Miscanthus sinensis 'Graziella', graziella miscanthus
  
• Miscanthus sinensis 'Malepartus', malepartus miscanthus
  
• Miscanthus sinensis 'Morning ight', morning light miscanthus
  
• Miscanthus sinensis 'November Sunset', November sunset miscanthus
  
• Miscanthus sinensis 'Sarabande', sarabande miscanthus
  
• Miscanthus sinensis 'Silberpfeil', Silverarrow miscanthus
  
• Miscanthus sinensis 'Strictus', porcupine grass
  
• Miscanthus sinensis 'Variegatus', variegated miscanthus
  
• Miscanthus sinensis 'Zebrinus', zebragrass
  
• Molinia caerulea 'Strahlenquelle', fountain spray moorgrass
  
• Pennisetum alopecuroides, fountain grass
  
• Pennisetum alopecuroides 'Hameln', hamlen dwarf fountain grass
  
• Pennisetum alopecuroides 'Weserbergland', weserbergland dwarf fountain grass
  
• Pennisetum orientale, oriental fountain grass
  
• Poa caesia, alpine bluegrass
  
• Poa chaixii, forest bluegrass
  
• Sesleria autumnalis, autumn moorgrass
  
• Stipa gigantea, giant feathergrass
  
• Stipa pennata, feathergrass

• Arundo donax, giant reed
  
• Arundo donax 'Variegata', variegated giant reed
  
• Arundo plinii, dwarf reed
  
• Briza media, quaking grass
  
• Carex buchananii, leatherleaf sedge
  
• Carex comans, New Zealand sedge
  
• Carex flagelifera, weeping brown New Zealand sedge
  
• Carex morrowi 'Old Gold', yellow variegated sedge
  
• Carex morrowi 'Variegata', variegated sedge
  
• Carex ornithopoda, birdsfoot sedge
  
• Carex ornithopoda 'Variegata', variegated birdsfoot sedge
  
• Carex pendula, drooping sedge
  
• Carex pilulifera 'Tinney's Princess', silver striped sedge
  
• Carex plantaginea, plantain leaved sedge
  
• Chasmanthium latifolium, northern seaoats
  
• Dactylis glomerata 'Variegata', Variegated orchardgrass
  
• Eragrostis trichodes, lovegrass
  
• Erianthus ravennae, hardy pampasgrass
  
• Erianthus contortus, bent-awn pluegrass
  
• Festuca alpestris 'Aureola', alpine fescue
  
• Festuca elegans, elegans fescue
  
• Festuca gautieri, bearskin fescue
  
• Festuca gigantea, giant fescue
  
• Festuca glacialis, glacier fescue
  
• Festuca rupicaprina, fescue
  
• Hakonechloa macra aurea, golden hakonechloa
  
• Holcus lanatus, velvetgrass
  
• Imperata cylindrica 'Red Baron', Japanese bloodgrass
  
• Luzula nivea, snowy woodrush
  
• Melica ciliata, hairy mellic
  
• Millium effusum, wood millet
  
• Millium effusum 'Aureum', golden wood millet
  
• Miscanthus sinensis 'Yaku Jima', Yaku Jima miscanthus
  
• Miscanthus transmorrisonensis, evergreen miscanthus
  
• Molinia caerulea 'Variegata', variegated moorgrass
  
• Pennisetum alopecuroides 'Moudry'/'Viridescens', black flowering fountaingrass
  
• Pao alpina 'Vivipara', alpine bluegrass
  
• Saccharum ravennae, plumegrass
  
• Scizachyrium scoparium 'Cimarron', little bluestem
  
• Stipa barbata, feathergrass
  
• Stipa capillata, feathergrass