100 Cold Hardy Trees Shrubs And Perennial For Kittitas Count

100 Cold Hardy Trees,Perennials, and Shrubs forKittitas CountyPrepared By Hilary Foss, Master Gardener CoordinatorPatrice Andersen, Master GardenerMary Vathauer, Master Gardener

100 Cold Hardy Trees, Perennials, and Shrubs for Kittitas CountyGardeners in Kittitas County face unique challenges. Cold winters and hot, dry summers, and lots of wind create a tough gardening climate. Additionally, ourcounty contains a wide range of eco-systems, with varying soils, soil pH, rainfall, and plant communities.At higher elevations such as Cle Elum (1,930 feet), the average growing season is 90 to 120 days with last frosts in late May (approximately May 24th) and first frosts inthe middle of September (approximately September 11th). Cle Elum receives about 22” of rain on average. At lower elevations such as Ellensburg, conditions are muchdrier and frost-free days are longer. The average growing season in Ellensburg is about 120 days with last frosts in early May (May 11th) and first frosts around the end ofSeptember (approximately September 25th). Kittitas County is rated at USDA Zone 5 (-20 F. minimum).Our tough climate with varying conditions can be baffling to first time gardeners, who are new to the area. A frequent question at our Master Gardener plant diagnosticclinic is “What can I grow here in Kittitas County?” This brochure is designed to help answer that question, listing trees, shrubs, and perennials that are suitable for thisarea.Table of Contents10 Hardy Shade Trees .2-3Commonly Used Trees that Pose Landscape Problems . 45 Hardy Evergreen Trees . 515 Hardy Shrubs .6-825 Hardy Perennials .9- 1210 Hardy Ground Covers .13-1410 Hardy Bulbs .15-165 Hardy Berries . 1710 Hardy Fruit Trees .18-1910 Hardy Climbers/Vines .20-215 Hardy Grasses . 22WSU EXTENSION KITTITAS COUNTY MASTER GARDENERS100 Cold Hardy Trees, Perennials, and Shrubs for Kittitas CountyPage 1

10 Hardy Shade Trees for Kittitas CountyGardeners often ask, “What shade trees can I grow in here in Kittitas County?” With our hot, often windy summers, care must be taken in choosing tree varieties that willtake our arid summer conditions. Of equal importance, shade trees must also be disease and insect resistant, and beautiful. While no tree is entirely immune to pest anddisease problems, some are resistant. Listed below are some of the hardiest and most disease and insect resistant varieties for our area.CommonNameBotanicalNameTreeHeightTree � to50’ tallBroad conical tree with five to sevenlobed, star-shaped, dark-green leaves,which turn red in the fall.Sun/partsun.May develop chlorosis in highpH soils.USDA Zone 5(-20 F.minimum)HackberryCeltisoccidentalis25’ to50’ tallFull sun topart shade.Deep rooting. Very hardy towind, heat, alkaline soil,pollution. Watch for aphids.USDA Zone 2(-45 s var.f. inermis35’ to70’ tallGood substitute for elm but smaller ¬ susceptible to Dutch Elm Disease.Rounded crown. Bright green, ovalleaves to 5”. Branches spreading &sometimes pendulous.Fast growing with upright trunk andspreading, arching branches. Providesnice, filtered shade. Leaves dividedinto many oval leaflets to 1-1/2” long.Poor to averagesoil, droughttolerant. Canwithstandcompacted soilVery soil and siteadaptable. Willtolerate somearidity.Good desert tree. Does bestwith sharply defined wintersand hot summers. Hardy.USDA Zone 2(-45 is’35’ to40’ tallFast growing with leaves divided intorounded leaflets. Clusters of sweetpea-shaped magenta flowers. Showy.Hardy.Full sun.Prefers moist, rich,alkaline soil, butwill toleratedrought, pollutionand salt.Adaptable to allsoil types. Needsno water onceestablished.All zones.JapaneseZelkovasyn.SawtoothZelkovaZelkova serrata40’ to60’ tallSmooth, gray bark like that of beech.Leaves to 3-1/2” long with saw-toothmargins. Colorful fall foliage.Full sun.Var. ‘Purple Robe’ has darkerflowers and blooms two weeksearlier and for longer period.Drawbacks include brittlewood and aggressive roots.Good substitute for insectplagued elm. Tolerant of windand drought.WSU EXTENSION KITTITAS COUNTY MASTER GARDENERS100 Cold Hardy Trees, Perennials, and Shrubs for Kittitas CountyFull sun.Page 2Prefers deep, moistsoil. Water deeplyto encourage deeprooting.USDA Zone 5(-20 F. orslightly colderextremes)

10 Hardy Shade Trees for Kittitas County - continuedCommonNameBotanicalNameTreeHeightTree USDAZoneKentuckyCoffee TreeGymnocladusdioica50’ to60’ tallFull sun.Adaptable to widerange of soils. Littlewater onceestablished.Hardy to heat, cold andpoor soil once established.Some litter created byseedpods and fallen leaves.USDA Zone 4(-30 F.minimum)LindenTiliaamericanaT. cordataT. tomentosaTo 60’To 50’To 50’Good tree for large areas. Leaves to 3’divided into leaflets to 3”, pinkishchanging to dark green, yellow in fall.Small flowers followed by 6-10’ pods.Bold winter display.Dense, compactly crowned. Small,fragrant flowers in drooping clusters,which are produced in midsummer.Full sun.Linden will toleratedry, heavy soils.Linden needs regularwatering.USDA Zone 4(-30 F.minimum)MaidenhairTreeGinkgo biloba35’ to50’ tallFull sun.MountainAsh(European)Sorbusaucuparia20’ to40’ tallNarrow to spreading or umbrellashaped. Graceful with broad, fanshaped leaves resembling themaidenhair fern, which turn gold infall and practically glow when backlitby the sun.Sharply rising branches. Dense, ovalto round crown. Leaves have 9-15leaflets to 2” long. Good autumncolor. Clusters of tiny, white flowersin spring followed by red, berrylikefruit.Water in dry seasonwhen tree is new, untilestablished when treehas grown 10’ to 20’tall. Prefers sandy,deep, moist soil.Needs good drainage.Moderate water onceestablished.T.cordata best as shadetree and has yellowflowers.T. tomentosa is heat anddrought tolerant and haswhite flowers.Plant only male trees.Females produce messy,smelly fruit. Maidenhairtree is resistant to insectsand root rot fungus.Sycamore(LondonPlane Tree)Platanusacerifolia syn.P. hispanica40’ to80’ tallLarge tree with maple-like leaves andinteresting exfoliating bark. Goodwinter interest. P. occidentalis(American Sycamore) is very hardyand has whiter bark.Full sun.WSU EXTENSION KITTITAS COUNTY MASTER GARDENERS100 Cold Hardy Trees, Perennials, and Shrubs for Kittitas CountyFull sun orlight shade.Page 3Prefers well-drainedsoil but will toleratemost soil conditions.USDA Zone 4(-30 F.minimum)Moderate to rapid growth.May grow much larger.Hardy to cold, wind, lowhumidity, and extremeheat.USDA Zone 2(-45 F.minimum)Needs lots of room.Cultivar ‘Blood-good’resists anthracnose fungaldisease.USDA Zone 5(-20 F.minimum)

Commonly Used Trees that Pose Landscape ProblemsEllensburg has many large, beautiful shade trees, which we all admire. Many times, home gardeners would like to grow these trees in their own yards and landscapes.Unfortunately many of these trees, although beautiful, aren’t good choices because of susceptibility to certain disease and insect problems. A list of these trees and theirproblems are as follows:Name of TreeBirch – BetulaspeciesInsect ProblemBronze Birch Borer,Aphids, Leaf MinersDisease ProblemNoneCommentsBirch trees like high humidity and lots of water. They are prone to bronze birchborer damage, making them poor landscape choices for our area.Crabapple –Malus speciesElm – SiberianUlmus pumilaApple Maggot, Aphids,Tent CaterpillarsElm Bark Beetles, Aphids,LeafhoppersScab, Cedar Apple Rust,Fireblight, Powdery MildewDutch Elm Disease, BacterialLeaf ScorchPlant resistant varieties such as Indian Magic, Professor Sprenger, Prairie Fire,Marry Potter, Molten Lava, or Sugar Tyme.Chinese elm (Ulmus parvifolia) is much more resistant to insect & diseaseproblems.Hawthorne –CrataegusspeciesHorse Chestnut– AesculusMaple – Silver& Red AcerspeciesOak – QuercusspeciesAphids, Borers, ScaleFungal Leaf Spot, PowderyMildew, Rust, Fireblight,Apple MaggotLeaf Blotch, Powdery MildewPlant resistant variety such as Crataegus x lavalle. Other problems withhawthorne trees are they are twiggy and have thorns.Willow – SalixspeciesGypsy MothAphids, Bladder Gall Mites,Box Elder Bugs, MealyBugs, ScaleBorer, Leaf Miner,Caterpillars, MitesAphids, Borers, Caterpillars,Leaf Beetles, ScalesAnthracnose, Leaf Scorch,Fungal Leaf Spot, PowderyMildew, Verticillium WiltOak Root Fungus, PowderyMildew, Anthracnose,Bacterial Leaf ScorchBlights, Canker, Fungal LeafGall, Willow ScabWSU EXTENSION KITTITAS COUNTY MASTER GARDENERS100 Cold Hardy Trees, Perennials, and Shrubs for Kittitas CountyHorse chestnut is somewhat susceptible to winter injury (frost cracks) and summerleaf scorch, as well as disease and insect damage.Silver maple grows quickly, which makes weak wood that breaks. Amur maple(Acer circinatum) or paperbark maple (Acer gingriseum) are better choices.Most oaks prefer acid soils and will not thrive in the alkaline soils of Eastern WA.Shingle oak (Quercus imbricarai) & Bur Oak (Q. macrocarpa) will tolerate ourhigh pH soils.Willows are prone to insect problems, willow borer damage in particular. They arealso very brittle and lose branches easily.Page 4

5 Hardy Evergreen Trees for Kittitas CountyMany gardeners like using evergreen trees in their home landscapes, because of the year round interest that these trees provide. Evergreen trees can also make goodwindbreaks or add privacy screening, which might be desirable. Some evergreen trees, especially our native species, are drought tolerant, which is useful for homelandscapes with limited water. The best choices for our area, are listed below:CommonNameBotanicalNameTreeHeightTree USDAZoneDouglasFirPsuedotsugamenziesii70’ to250’ tallFull sun orpart shade inyouth.USDA Zone 4(-30 F.minimum)Larix spp.70’ to100 ’tallAll but undrained, swampysoils. Little or nowater onceestablished.All soil types.Prefers moistconditions.Douglas Fir is a beautiful landscapetree that is hardy to wind. Resistant tooak root fungus.LarchNotable for color in spring and falland nice silhouette in winter.Dropped needles can be a mess in thefall. This tree is attractive to birds.USDA Zone 3(-40 F.minimum)LodgePole PinePinuscontorta var.latifolia80’ tallPyramidal form. Soft, medium greenneedles. Oval cones to 3” long.Older trunks divided by thick,reddish-brown ridges. Tassels of newgrowth on tips in spring.Deciduous conifer with slender,pyramidal habit, with droopingbranches. Tufts of bright green,fluffy needles. Woody, roundedcones. Needles pale green in spring,yellow to orange in fall beforedropping.Tall conical, evergreen tree withneedles in bundles of 2.Lodgepole pine has attractive, densefoliage. Nice used as a specimen tree.USDA Zone 5(-20 F.minimum)Ponderosa PinePinusponderosa50’ to150’ tallLarge, open growing conifer.Needles are dark green, 4-6” inbundles of three.Cones to 5” long. Exfoliating bark.Full sun.Poor to averagesoil, droughttolerant. Canwithstandcompacted soil.Hardy & tolerantof poor soil.Regularwatering.USDA Zone 3(-40 F.minimum)SprucePicea spp60’ to150’ tallLarge, pyramidal, cone-bearing tree.Short, stiff, blue-green needlesspreading around branches. Manykinds have dwarf varieties. Allattractive to birds.Full sun tolight shade.Signature native tree in InlandNorthwest. Can be maintained as ahedge. Susceptible to pine bark beetlein trees under stress. Prevent bykeeping trees thinned and wellwatered. Also susceptible to westerngall rust, pine needle scale and pineshoot moth.Norway Spruce (Picea abies) isextremely hardy & wind resistant.Good choice for wind breaks.Englemann Spruce (P. engelmannii)has softer needles. Colorado BlueSpruce (P. pungens) tolerates drought.Subject to Cooley spruce gall adelgid.P. pungens ‘Glauca’ (Colorado BlueSpruce) has blue-green coloring.WSU EXTENSION KITTITAS COUNTY MASTER GARDENERS100 Cold Hardy Trees, Perennials, and Shrubs for Kittitas CountyFull sun.Sun/partsun.Page 5Moist, welldrained soil.USDA Zone 2(-45 F.minimum)