Evergreen Shrubs Part2
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Evergreen Shrubs1 Cold Pests / Diseases & Flowers5 / Fruit5 / Additional Name2 Hardiness Soil / Climate Size4 Exposure Zone3 Other Problems Foliage Features Buxus spp. 4A-9B Prefers moist, cool No serious insect or disease H: 2-5’ Full sun to Flowers – small, petaless, Introduced from Asia, sites, but will grow problems. S: 2-5’ partial shade. greenish-yellow, Europe, and northern Boxwoods on most soils Boxwood bight, caused by a insignificant, but fragrant; Africa; form is upright- regardless of pH so attractive to bees; insect oval to rounded; tolerates fungus, is a potential long as they are not Must be in pollinated. pruning and can be kept problem should this disease winter shade too wet or too dry; find its way to Minnesota. Bloom Time – spring (May). small by shearing; a mulching is number of named cultivars Buxaceae recommended. Winter injury can Foliage – broadleaf (cultivated varieties) have Boxwood Family sometimes be a problem on evergreens; leaves small, been selected based on exposed sites during severe broadly oval to elliptical, size, form, foliage winters. opposite, variously light to characteristics, and cold Deer and rabbit resistant. dark green, becoming hardiness; the species is yellowish-green to brownish- propagated by seeds and Buxus microphylla var. koreana (Korean littleleaf boxwood) and its cultivars and several cultivars resulting green in winter. stem cuttings and the from crosses between this species and Buxus sempervirens (common boxwood; also called English boxwood) Fruit – a 3-celled capsule; cultivars by stem cuttings. are the best choices for Minnesota landscapes (e.g., ‘Glencoe’ (Chicagoland Green®*), ‘Green Gem, ‘Green green becoming tan and Mound’, ‘Green Velvet’, ‘Saskatoon’, ‘Wilson’ (Northern Charm™*), and ‘Wintergreen’); common boxwood containing shiny, black is more commonly grown in warmer areas (Zones 6 and above), but isn’t reliably hardy in Minnesota. seeds; insignificant; matures in late summer (September). Juniperus spp. 3B-7B Adaptable; prefers Few pests are serious, but H: 1-20’ Full sun. “Flowers” – male and female Widely distributed Some hardy moist, well-drained Phomopsis blight S: 3-20’ strobili (cones) usually throughout the Northern Junipers to Zone 2 soils, acidic or (Phomopsis juniperovora) produced on separate trees Hemisphere and into alkaline, but will and spider mites can (dioecious; individual trees northern Africa; 13 species grow on almost any sometimes be a problem. male or female); male pollen are native to North soil so long as it is cones small, yellowish-tan, America and three to Some species (mainly well-drained. Juniperus scopulorum and catkin-like with 6-12 scales, Minnesota; the native Cupressaceae and produced at the tips of species and introduced Cypress Family Tolerant of air Juniperus virginiana) are pollution, drought, susceptible to cedar/apple/ the previous year’s species from Europe and and high pH hawthorn rust which branchlets (although not Asia are most commonly (alkaline) soils. alternates between junipers expanded, the cones are planted in Minnesota; and apples/hawthorns as visible in the fall of the typically have a single Intolerant of previous year and during the trunk, but branches close to flooding. alternate hosts (the spores produced on junipers infect winter and can be fairly the ground and can appear apples and hawthorns and showy when they open to to have multiple stems; vice versa); apples and shed their pollen in the bark reddish-brown, hawthorns that are not spring); female seed cones exfoliating (peeling) insignificant, yellow-green, vertically in strips; form is resistant can be defoliated, at the tips of the previous variable – columnar, but the junipers are year’s branchlets; wind broadly-pyramidal, generally not harmed. pollinated. rounded, spreading, and “Bloom Time” – spring prostrate; many named (May). cultivars have been selected based on form and Foliage – needle-leaf foliage and fruiting evergreens; individual characteristics; the species The junipers that are most commonly planted in Minnesota landscapes include needles live for 4-6 years; are propagated by seed and Juniperus chinensis (Chinese juniper), Juniperus communis (common juniper), needles green to bluish- the cultivars by stem Juniperus horizontalis (creeping juniper), Juniperus procumbens (Japanese garden green, opposite or in whorls cuttings and grafting. juniper), Juniperus sabina (savin juniper), Juniperus scopulorum (Rocky Mountain of three; two types of leaves juniper), and Juniperus virginiana (eastern redcedar); Juniperus communis (var. are produced – sharp, needle- depressa – ground juniper, dwarf juniper, or prostrate common juniper), Juniperus like, juvenile leaves are horizontalis, and Juniperus virginiana are native to Minnesota. produced on young plants and sometimes on vigorous shoots of older plants and overlapping, scale-like leaves are produced on older plants; foliage sometimes and variously becomes maroon to purplish-brown in the winter. “Fruit” – female cones (strobili) are berry-like, green to blue-green, waxy, and contain 1-3 seeds; mature in fall (August/ September), but never open. Pinus mugo 3A-7B Quite adaptable; Susceptible to a variety of H: 3-20’ Full sun. “Flowers” – male and female Introduced from the prefers moist, pest problems, but, with the S: 3-25’ strobili (cones) produced on mountainous areas of Mugo Pine loamy, well-drained exceptions of sawfly larvae the same tree (monoecious); central and southern soils, but will grow and scale, most are usually male pollen cones yellow; Europe; size and form are Swiss Mountain on most soils so not serious enough to female seed cones purple- highly variable – prostrate, Pine long as they are warrant control. tinged; wind pollinated. mounded, irregular, or well-drained. “Bloom Time” – spring pyramidal; several named Tolerates drought (May). cultivars have been selected based primarily on and vulnerable to Foliage – a needle-leaf Pinaceae flooding. size and form (mainly Pine Family evergreen; leaves (needles) smaller, more compact medium to dark green in Mugo pines sold by nurseries and garden centers are often seed produced and can be plants); the species and pairs, sometimes becoming quite variable in habit and mature size; as a result these plants can grow to sizes much varieties are propagated by yellowish-green in winter; larger than expected if they are not regularly pruned (sheared) to maintain their size. In seed and the cultivars by needles live for five years or addition, although not covered here, shrub forms of other species of pines (Pinus spp.), grafting. more. as well as other needle-leaf evergreens like firs (Abies spp.), hemlocks (Tsuga spp.), and spruces (Picea spp.), are also used in designed landscapes; these selections are “Fruit” – female cones often referred to as dwarf conifers. (strobili) small, green, becoming gray-brown when mature; mature and open in fall (August/September) to release the winged seeds; empty cones persistent. Rhododendron 4A-7A Most perform best Quite a few, but most are H: 3-8’ Full sun to Flowers – very showy, white Native to many parts of the spp. on organic, cool, not serious; powdery S: 3-8’ partial shade; and various shades of world, most of the species moist, but well- mildew, leaf spots, aphids, best in partial yellow, orange, pink, and grown in Minnesota are drained, acidic (low and spider mites are most shade and rose, in dense, terminal native to Asia and eastern Azaleas & pH) soils. common. especially clusters (racemes or North America; none are Rhododendrons Generally intolerant during the corymbs); fragrant; insect native to Minnesota; form winter in cold pollinated. is upright oval to rounded; of alkaline (high pH) soils and heat climates. Bloom Time – spring the genus Rhododendron and drought. (May/June). includes both deciduous Ericaceae and evergreen species Heath Family Foliage – broadleaf (azaleas tend to be evergreens; leaves light to deciduous and Rhododendron ‘P.J.M.’ (‘P.J.M.’ rhododendron), a hybrid selection resulting from a dark green, alternate. rhododendrons evergreen, cross between Rhododendron carolinianum and Rhododendron dauricum, is the but in both cases there are evergreen species that is most commonly planted in Minnesota landscapes; the Fruit – a capsule; green, exceptions; see the flowers are lavender-pink and open in May; if the growing conditions are otherwise becoming brown; deciduous shrubs list for ideal (acidic, moist, but well-drained soils), this species is hardy in Zone 3B; the insignificant; matures in fall deciduous species); the leaves have a plum-purple color during the winter; interestingly, the leaves roll up (August/September). species are propagated by longitudinally when temperatures drop below freezing. seeds and stem cuttings and the cultivars by stem cuttings and tissue culture. Taxus spp. 4A-7B Prefer moist, sandy Mites, aphids, scales, and H: 3-4’ Full sun to “Flowers” – male and female Native as an understory loam soils, but will others, but no pests of major S: 8-10’ shade, but strobili (cones) usually species in forests in Yews grow on most soils concern. requires winter produced on separate plants Europe, Asia, and North regardless of pH Browsed on by deer during shade. (dioecious; individual plants America including (acidic or alkaline) male or female); male pollen Minnesota; Taxus mid to late winter. so long as they are cones small, catkin-like, cuspidata (Japanese yew; well-drained. rounded, yellow with only a several cultivars) and Taxaceae few scales in the axils