Alternatives to Invasive Shrubs

Transcription

1 Alternatives to Invasive Shrubs Many invasive shrubs have been planted over the years as landscape plants in yards. Unfortunately, many of them have escaped the yards and spread all over the landscape. Removing these invaders and using better, non-invasive alternatives is the proper way to proceed with our landscape. Please see the list below for invasive shrubs, which can all be searched online for photos. Better alternatives are listed on the following pages. Credit to Laura G. Jull, Ph.D., UW-Madison: The Wisconsin Arborist newsletters from fall and winter Invasive Shrubs: WI DNR classifications: P= Prohibited R= Restricted *Considered invasive by Midwest Invasive Plant Network (MIPN) but not in DNR NR-40 list Berberis koreana: Korean Barberry and hybrids of it- R Berberis thunbergia: common barberry- P Caragana arborescens: Siberian pea-shrub- R Cytisus scoparius: Scotch-broom- R Elaeagnus angustifolia: Russian olive- R Elaeagnus umbellate: autumn olive- R Euonymous alatus: Burning bush- R Fallopia bohmica: Bohemian knotweed- P Fallopia japonica: Japanese knotweed- R Fallopia japonica var. compacta: Dwarf Japanese knotweed- R Fallopia sachalinensis: giant knotweed- P Frangula alnus: glossy buckthorn- R *Lespedeza bicolor: shrubby lespedeza *Ligustrum amurense: Amur privet *Ligustrum obtusifolium: border privet *Ligustrum vulgare: European privet Lonicera bella: Bells s honeysuckle- R Lonicera maackii: Amur honeysuckle- P/R Lonicera morrowii: Morrow s honeysuckle- R Lonicera tatarica: Tartarian honeysuckle- R *Lonicera xylosteum: European fly honeysuckle Rhamnus cathartica: common buckthorn- R Rhodotypos scandens: black jetbead- R Robinia hispida: rose acacia, bristly locust- R Rosa multiflora: multiflora rose- R Rubus bifrons: Himalayan blackberry- P Rubus phoenicolasius: wineberry- P *Sorbaria sorbifolia: Ural flase-spirea *Spiraea japonica: Japanese spirea *Tamarix chinensis: salt-cedar, tamarisk *Viburnum opulus: European cranberrybush viburnum

2 Alternative Shrubs: Listed below are ornamental deciduous and evergreen shrubs which can replace invasive and overused shrub species in urban areas, parks, lawns, and landscapes. There are so many to choose from so they are limited by category to four alternative shrubs. There is a hardiness zone map at the end of this list. 1) Shrubs with purple to red leaves: Instead of the invasive purple leaf Japanese barberry and its hybrids, use some of the below shrubs for color throughout the growing season. Cotinus coggygria: smokebush; large flowering shrub; tall and wide with upright branches, small yellow flowers turn smoky pink to purple due to hairs on flower stalks that resemble puffs of smoke; flower puffs last most of summer; adaptable to most soils and ph; needs full sun for purple leaved cultivars; drought tolerant and deer resistant; resistant to Japanese beetles; susceptible to Verticillium wilt; hardy to zone 4a-5. NCC01 Winecraft Black new cultivar; semi-dwarf growing only 5-6 tall, purplish-black leaves darken during summer; hardy to zone 4b Figure 1 Smokebush -Royal Purple cultivar Nordine most cold hardy purple-leaved cultivar; purple new leaves with bluish-green older leaves, zone 4a Royal purple dark purple leaves with purple to pink flowers; 8-10 tall and wide. Hardy to zone 5. Physocarpus opulifolius: eastern ninebark; native to Wisconsin; grows 3-10 tall and wide depending on cultivar; creamy white to pinkish white flower in late spring; red, dry fruit in cluster in summer fade to brown; reddish brown bark in papery strips; adaptable to most soils and ph; needs full sun and good air circulation for purple leaved cultivars to retain color and to reduce conditions favourable for powdery mildew; can get fireblight; Japanese beetle resistant; drought and heat tolerant once established; zone 3a. ARTBOE401 Red Robe yellow-orange spring leaves age to burgundy-red; 6-8 tall, 7-9 wide; upright form. Center Glow yellow-green new leaves turn bright red; susceptible to powdery mildew; 8-10 tall and wide Figure 2 Eastern Ninebark Diablo cultivar

3 Donna May Little Devil dwarf form; 3-4 tall and wide; small burgundy leaves; pinkish white flowers; Jefam: Amber Jubilee orange, yellow, and gold leaves; rounded upright form; purple fall color; full sun Minall2 : Black Jack black-purple leaves; dense and round; 4 tall and wide Mindia: Coppertina copper new leaves turn reddish in summer; 6-8 tall and wide; very susceptible to powdery mildew Monlo : Diabolo vigorous; reddish purple large leaves; purple stems; gets large; gets powdery mildew Podaras 1 : Gumdrop Burgundy Candy : deep burgundy leaves; 3-5 tall and wide, reddish fall color; powdery mildew resistant Seward : Summer Wine : Deeply cut purple leaves; 5-6 tall; reddish fall color; powdery mildew resistant SMNPOBLR : Ginger Wine : orange-red and bright burgundy leaves in summer; compact, upright form; 5-6 tall and wide; powdery mildew resistant SMPOTW : Tiny Wine : dwarf form; 3-4 tall and wide; smaller, dark bronze-maroon leaves; blooms up and down the stem with pinkish white flowers; powdery mildew resistant Tuilad : Lady in Red : large, pink flowers; burgundy fruit; bright red spring leaves turn glossy chestnut red in summer; compact form; 4-6 tall and wide. Sambucus nigra: European elderberry; Fast growing, suckering, arching branches; creamy white to pinkish white flowers in summer; purplish black fruit in clusters in late summer; entire plant poisonous except for ripe fruit juice; adaptable to most ph and soils, except heavy clay; full sun to retain color; wet soil and drought tolerant; needs renewal pruning; resistant to Japanese beetles; hardy to zone 4b-5a Effel01 : Black Tower : 6-8 tall 3-4 wide. New growth is green turning dark burgundy. Eva : Black Lace : lacy, dark purple, fine textured leaves; large pink flowers in summer; black fruit in fall; 6-10 tall and wide. Gerda : Black Beauty : dark purple Figure 3 Sambucus nigra 'Gerda': Black Beauty cultivar leaves; large pink flowers in summer; black fruit in fall; 6-8 tall, 3-4 wide. SNR1292 : Strait-Laced : upright form with curving stems; 6-8 tall; fine textured leaves.

4 Weigela hybrids: 3-6 wide and tall; twiggy, dense to rounded form; showy, tubular flowers in late spring, easy to grow and adaptable to most soils and ph; drought tolerant; intolerant to wet soils and poor drainage; needs full sun for purple cultivars to retain color. Figure 4 Weigela spp. Midnight Wine cultivar Alexandra : Wine and Roses 4-5 tall and wide; hot pink flowers. Bokraspiwi : Spilled Wine dark red, wavy leaves; spreading form 2-3 tall and 3 wide; hot pink flowers; zone 5 Bramwell : Fine Wine dark burgundy, smaller leaves; compact, mounded form; small pink flowers; hardy to zone 5. Elvera : Midnight Wine : smallest cultivar; dwarf; low mounding form; rarely flowers; hardy to zone 5 Tango : compact form; purple leaves red flowers with yellow throats; most cold hardy; hardy to zone 4. 2) Shrubs for narrow, hedges: Instead of tall hedge buckthorn, choose these shrubs for a narrow to tall hedge that can be sheared. Buxux Green Mountain : Green Mountain boxwood; upright,pyramidal form tall, 3 wide; dark evergreen leaves stay green all winter; can be sheared into a formal hedge; requires a rich, loamy, moist, well-drained soil; intolerant to heavy clay, compact soil, and droughts; full sun to full shade; avoid exposure to winter burn; Japanese beetle and deer resistant. Zone 5a. Figure 5 Buxus ' Green Mountain' Boxwood Cotoneaster acutifolius var. lucidus: Hedge cotoneaster; upright to rounded spreading form; 6-10 tall and wide, can be sheared into formal hedge; small pinkish-white flowers in late spring; shiny black fruit if not sheared; turns reddish orange in fall; if soil is well drained, is drought, urban and salt tolerant; can get fireblight; hardy to zone 3a. Figure 6 Cotoneaster acutifolius var. lucidus

5 Taxus media: Anglo-Japanese yew; soft, flat, dark evergreen leaves can be sheared into formal hedge; dioecious; choose male cultivars to avoid poisonous fruit, requires a sandy loam, well-drained soil. Intolerant to heavy clays, road salt, compacted soil, and poor drainage; full sun to full shade; can winterburn in full sun; Japanese beetle resistant. Beanpole : narrow, upright, columnar form; 10 tall 2 wide; female plant; may winterburn Citation : tall and narrow; dark leaves. Hicksii : tall becoming wide with age; susceptible to winterburn; male and female clones exist. Viridis : Tall and narrow; male plant; winterburn resistant; wide, dark green leaves. Figure 7 Taxus media: Anglo-Japanese yew 'beanpole' cultivar Thuja occidentalis: Northern white cedar; can be sheared into a formal hedge; dense, narrow, dark green, evergreen leaves; full sun to partial shade; very susceptible to deer browsing; resistant to Japanese beetles; hardy to zone 3a. Figure 8 Thuja occidentalis: Northern white cedar Art Boe : North Pole Tall, narrow, tall form, resistant to winterburn. Brabrant : Upright, narrow form; bright green leaves. Degroot s Spire : narrow, columnar form; fine textures, scalloped to fern-like, dark green leaves; resistant to winterburn. Hetz wintergreen : pyramidal, narrow form, with a central leader; fast growing. Holmstrup : formal, dense, narrow to conical shape; slow grower; vertical foliage through winter. Nigra : dark green arborvitae; narrow and dense form; tall; resists winterburn. Rushmore : compact and narrow;dark green leaves through winter; resists winterburn. Smaragd : emerald arborvitae; narrow, dense, tight, compact, columnar form; vertical leaves through winter; winterburn resistant; only hardy to zone 4a. SMTOBP : Skywalker : narrow, conical form; tall and 3 wide; evergreen leaves; resists winterburn.

6 3) Shrubs with showy, fragrant flowers: Instead of using invasive shrub honeysuckles (Lonicera bella, L. maackii, L. morrowii, L. tatarica), choose these plants for spring or summer, fragrant flowers. Abelia mosanensis: Korean abelia, fragrant abelia; rounded to spreading form with arching branches, fast grower; glossy, clean leaves; rose-pink to white fragrant flowers open in midspring; orange-red fall color; requires a rich loamy soil; slightly acidic to neutral ph; full sun to partial shade; Japanese beetle and deer resistant; hardy to zone 4b. SMNAMDS : Sweet Emotion : orange-red fall color. Figure 9 Abelia mosanensis: Korean abelia or fragrant abelia Clethra alnifolia: summersweet clethra, sweet pepperbush; upright, oval to rounded form; suckering; slow grower; very fragrant; summer white or pink flowers in a spike; yellow golden fall color; requires, rich loamy, fertile, moist, slightly acidic soil high in organic matter; full sun to partial shade; tolerates wet soil; deer resistant; susceptible to Japanese beetles; hardy to zone 4b. Caleb : Vanilla Spice : white flowers on longer spikes. Crystalina : Sugartina : Improvement over hummingbird cultivar. Hummingbird : white flowers; golden brown fall color. Ruby Spice : reddish fragrant flower do not fade to white; yellow fall color; slightly taller. Figure 10 Clethra alnifolia: summersweet clethra 'Vanilla Spice' cultivar Sixteen candles : white fragrant flowers, dark green glossy leaves. September Beauty : upright form; flowers later; glossy leaves.

7 Syringa spp.: (Lilacs) Thousands of species and cultivars available; most grow very large in the landscape; full sun only; requires well-drained soil; all are resistant to Japanese beetles. Syringa Josée : rounded dwarf form; non-suckering;4-5 tall, 5-6 wide; flowers can re-bloom in summer; resists powdery mildew; heat tolerant; hardy to zone 4. Syringa meyeri Palibin : 5-6 tall and wide; fragrant; pale purple flowers; powdery mildew resistant; non-suckering; hardy to zone 4a. Syringa pubescens sunsp. patula Miss Kim : 5-8 tall and 6-8 wide; fragrant; non-suckering; pale purple flowers; resists powdery mildew; hardy to zone 4a. Syringa Red Pixie : Rounded with horizontal branches 4-6 tall and wide; non-suckering; dark red to magenta flowers fade to light pink; powdery mildew resistant; hardy to zone 4. Syringa vulgaris: common lilac; intensely fragrant; most get too large, below is dwarf culture. Elsdancer : (Tiny Dancer ) dwarf plant only 4-5 tall and wide; heat tolerant; powdery mildew resistant; fragrant purple-lavender flowers; hardy to zone 3. Figure 11 Syringa vulgaris: common lilac Viburnum carlesii: Koreanspice viburnum; compact, mounded, dense form; slow growing; very fragrant white flowers open in May; reddish-burgundy fall color; requires a rich loamy, fertile, moist, welldrained soil; ph adaptable; intolerant to road salt; full sun to partial shade; resists Japanese beetle; hardy to zone 4. Compactum : compact, dwarf form; 4-5 tall and wide; dark green leaves. J.N. Select : Spiced Bouquet : Glossy, dark green leaves; 5-6 tall and wide; wine-red fall color. J.N. Select A : Spice Island : better branching; compact round form; wine-red fall color. J.N. Select S : Sugar and Spice : produces lots of small flowers; 6-8 tall and wide; wine-red fall color. SMVCB : Spice Baby : compact, rounded form; tall and 4 wide. Spiro : Spice Girl : deep reddish-pink flowers; 5-7 tall and wide. Figure 12 Viburnum carlesii 'Compactum' cultivar

8 4) Shrubs with beautiful fruit: Instead of using the invasive privets (Ligustrum amurense, L. obtusifolium, L. vulgare), barberry (Berberis spp.), or shrub honeysuckles (Lonicera spp.), choose these plants for showy fruits. Callicarpa dichotoma: Purple beautyberry; mounded form with arching branches; 3-4 tall and wide; small pinkish lavender flowers in summer; bright, metallic, long-lasting, violet fruit fall; yellow to purple fall color; adaptable to most well drained soil and ph; drought and urban tolerant; intolerant to wet soil; resistant to Japanese beetles; full sun only; hardy to zone 5a; may dieback to ground in winter, but still flowers and fruits later that year. Figure 13 Callicarpa dichotoma Early Amethyst and Issai : produce bright purple fruit that appear earlier than the species. Cotoneaster apiculatus: cranberry cotoneaster; mounded, wide spreading; stiff, horizontal to arching branches; 2-3 tall, 4-6 wide; slower grower; small, glossy, dark green leaves; reddish-purple fall color; tiny pink flowers in spring; persistent red fruit into late fall; moderate salt tolerance; full sun only; susceptible to rabbit and vole injury under branches; can get fireblight; resistant to Japanese beetles; hardy to zone 4b. Figure 14 Cotoneaster apiculatus Ilex verticillata: winterberry or Michigan holly; native to WI; form and size varies with cultivar; suckering, can form colonies; 6-9 tall and wide; slow grower; tiny white flowers in spring; very showy bright red, orange, or yellow fruit in early fall to winter; requires male pollinator plant nearby; requires moist, rich, loamy, slightly acidic soil high in organic matter; intolerant to high ph; Japanese beetle and deer resistant; hardy to zone 3b; many cultivars.

9 Afterglow : female plant; dense form; reddish-orange fruit; use Jim Dandy as male pollinator. Winter Gold : female plant; gold fruit; 6-8 tall; use Southern Gentleman as male pollinator. Red Sprite : female plant; dwarf; large, bright red fruit; 3-4 tall and wide. Use Jim Dandy as male pollinator. Jim Dandy : Pollinator for early flowering cultivars Southern Gentlemen : Pollinator for later flowering cultivars. Figure 15 Ilex verticillata 'Red Sprite' Viburnum cassinoides: withe-rod viburnum, or northern wild raisin; native to WI; 5-6 tall and wide; dense, compact, rounded form; dark green, glossy leaves; orange-red to crimson-purple fall color; showy, creamy white, flat-topped flower clusters in late June to early July; green fruit turn bright pink in Sept., then bright blue, and finally to black; grows best in rich, loamy, fertile, well-drained soil; intolerant to drought, road salt, and urban conditions; tolerant to wet soil; full sun to partial shade; resistant to Japanese beetles; hardy to zone 3b. Requires another cultivar for pollination and fruit set. Figure 16 Viburnum cassinoides J.N. Select : Freedom : 5 tall and wide; maroon red fall color; compact form. KLM B : Buccaneer : 4-6 tall, 4-7 wide, rounded form; orange fall color. KLM C : Challenger : 5-8 tall and wide; rounded form; orange fall color. SMNVCDD : Lil Diddy : 1-2 tall, 2 wide; dwarf, compacted form; reddish fall color. 5) Shrubs with good fall color: Instead of using the invasive burningbush (Euonymus alatus), use these plants for showy fall color in addition to several plants listed above. Aronia melanocarpa: black chokeberry; native to WI; upright to rounded form; suckering, can form large colonies;5-8 tall and 6-10 wide; wide, glossy, dark green leaves; orange fall color; showy white flower clusters in mid spring; glossy, black, edible but bitter fruit in pendulous clusters in late summer to winter; fruit high in Vitamin C; adaptable to most soils and ph;

10 tolerant to wet soil, drought, and road salt; full sun to partial shade; can get leaf spot and Japanese beetles; hardy to zone 3b. Autumn Magic : 4-5 tall, 3-4 wide; upright, compact form; suckering; reddish purple fall color. Morton : Iroquois Beauty : 3-4 tall, 4-5 wide; compact, rounded form; suckering; opens with age. UCONNAM165 : Low Mound Hedger: wide; 1-2 tall, 2 wide; used as tall ground cover; red-orange fall color. UCONNAM166 : Low Scape Hedger: 3-5 tall, 2-3 wide; used as a hedge; bright orange fall cover; no fruit as is a triploid plant. Viking : 5-7 tall, 5-6 wide; flowers earlier than species; large black fruit. Figure 17 Aronia melanocarpa 'Viking' cultivar Fothergilla spp.: All Fothergillas have outstanding, late, yellow-orange to bright red fall color; showy, long-lasting, white honey-scented flowers in mid spring; requires a rich, loamy, moist, well-drained soil high in organic matter; acidic ph; full sun to partial shade; intolerant to drought, high ph, road salt, heavy clay, compacted soil; prone to rabbit damage; resistant to Japanese beetles; hardy to zone 4. Fothergilla gardenii: dwarf form; slow grower, dense form. Figure 18 Fothergilla 'Blue Mist' cultivar Blue mist : blue green leaves; weak grower; not as cold hardy; yellow-orange fall color. KLMtwo : Beaver Creek : compact, uniform, rounded form; red-orange fall color. Windy City : blue-green leaves; rounded form; gold to red fall color. Fothergilla X intermedia Mt. Airy : upright form 5-6 tall; dark blue green leaves; large flowers; red fall color. Blue Shadow : very showy; dusty blue to silvery blue leaves; red-orange fall color.

11 Rhus aromatic Gro-low : Gro-low fragrant sumac; native to WI;straight species grows 4-6 tall and 6-8 wide; gro-low only gets 2-3 tall and 6 wide; wide-spreading; tall groundcover; glosser, dark green leaves; orange, red to purple fall color; small yellow flowers at branch tips in early spring; male cultivar with few or no fruit; drought, urban, road salt, and heat tolerant; full sun only; can get verticillium wilt; resistant to Japanese beetles; hardy to zone 3b. Figure 19 Rhus aromatica 'Gro-low' fragrant sumac Viburnum prunifolium: blackhaw viburnum; native to WI; large shrub to small tree; rounded form with horizontal branches; suckering; reddish-purple to maroon fall color; showy, creamy white flower cluster in late spring; edible fruit in early fall; requires cross pollination for good fruit set; grows best in rich, fertile, loamy, moist, well-drained soil; full sun to partial shade; moderate drought and road salt tolerance; less susceptible to powdery mildew than nannyberry viburnum (Viburnum lentago); resistant to Japanese beetles; hardy to zone 3b. MckRouge : Forest Rouge : more uniform habit; oval to upright form; tall and wide; reddish purple fall color; needs another cultivar for pollination and fruit set. Summer Magic : compact form; 6-10 tall;green leaves with reddish tips; maroon fall color; needs another cultivar for pollination. Figure 20 Viburnum prunifolium 'MckRouge' cultivar

12 Figure 21 USDA plant hardiness zone map