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					                                                                                                                Trees, Shrubs

MU Guide

                        Selecting Landscape Plants:
                            Needled Evergreens
                                                  Christopher J. Starbuck
                                                 Department of Horticulture

       Needled evergreens, often known as narrow-leaved
  evergreens or conifers, are planted primarily because of
  their evergreen foliage. But the many sizes, shapes and
  colors available also contribute to their popularity (see
  Figure 1).
       Conifers range in size from prostrate plants growing
  only a few inches tall to large trees. Shapes include flat,
  groundcover types, horizontal spreaders, upright pyra-
  midal forms, and even weeping and contorted shapes.
  Foliage color ranges from a gold and cream variegation
  to all shades of green, gray-green and blue-green.
       Poorly drained soil, planting too deeply and winter
  drying are the most common causes of damage or death
  of needled evergreens. Most are killed easily by water
  standing at their roots. They must be planted in well-         Figure 1. Needled evergreens come in many shapes and sizes.
  drained soil. A raised bed may be the solution for
  planting on excessively wet sites. See MU publication          Metal or plastic containers must be removed before
  G 6955, Improving Lawn and Landscape Soils, for more           planting.
  details.                                                            Fertilizing at planting time may injure new roots. Do
       Plant an evergreen with the ball of soil an inch or       not fertilize evergreens until they have had at least one
  two higher than it grew in the nursery. Dig the planting       growing season to become established. Plants that have
  hole at least 1 foot wider in diameter than the soil ball.     good color and are making satisfactory growth probably
  After the plant has been put in position, backfill around      don’t need fertilizer. Plants weakened by insects, dis-
  it with good topsoil. If good topsoil is not available,        eases, poor drainage or infertile soil may respond to fer-
  mix 25 percent peatmoss, compost or similar organic            tilizer. If fertilizer is necessary, it should be applied
  material with the existing soil to provide a suitable          between mid-October and mid-March.
  substitute.                                                         The conifers commonly grown in Missouri can be
       Winter drying is a problem of all evergreens. The         divided into the nine groups described in the following
  evergreen foliage may lose moisture in the winter when         sections.
  cold or frozen soils make it difficult for roots to replace
  moisture as fast as it is lost. If the summer or fall has      Pine
  been dry, thoroughly soak the area around the plants in             The pines can be easily
  late November so the plants go into winter with an ade-        distinguished from other
  quate moisture supply to help prevent the problem. Less        evergreens because their
  winter-hardy evergreens should be planted in areas pro-        needle-like leaves are pro-
  tected from winter sun and wind to prevent winter              duced in bundles of two to
  damage and ensure their survival.                              five needles. Pines are used
       Evergreens are sold either balled-and-burlapped or        for screens, windbreaks and
  in containers. The burlap may be left on the ball for          mass plantings or are
  planting. Loosen the burlap from around the trunk and          planted as specimen trees.
  tuck it under the sides of the ball. Be especially careful     They need full sunlight to
  to remove any string or wire wrapped around the stem.          develop properly.

  $.75                                                      G 6815                                Printed on recycled paper
                                                                  Figure 4. Mugo pine

Figure 2. Austrian pine.        Figure 3. Scotch pine.

      Many species of pine can be grown in Missouri.              called pine wilt. It is also commonly affected by pine
However, the five species described in the following sec-         needle scale and needle blights.
tion are the ones most commonly grown as ornamentals.                  Japanese black pine (Pinus thunbergi). Japanese
Four of these species grow to be large trees. The other           black pine produces its stiff, dark green, 3- to 5-inch-long
(mugo pine) is a shrub.                                           needles in bundles of two. Its large, grayish white ter-
      White pine (Pinus strobus). The delicate, soft, light       minal buds help distinguish it from most other pines.
bluish-green foliage of the white pine makes an attrac-                The popularity of Japanese black pine has increased
tive evergreen tree. It is easily recognized because it is        during the past few years, primarily because of its
the only commonly grown five-needled pine. White                  informal growth habit. This irregular growth habit
pine is easily transplanted and fast growing. Since it will       makes it a good accent or specimen plant for use in
become a large tree, it needs adequate room to develop            informal landscapes but does not make it well suited for
properly.                                                         mass plantings. In Japan, forests of this pine species have
      On favorable sites, white pine sometimes grows too          been susceptible to pine wilt disease.
fast to retain its dense foliage. This can be avoided by               Mugo pine (Pinus mugo). Mugo pine is a shrub with
pruning the tree to increase its density. However, in             a dense, rounded growth habit (Figure 4). It is an excel-
pruning white pine, note that needles are not produced            lent small evergreen shrub. Plants of Mugo pine show
evenly along the stem but are clustered near the tip.             a wide variation in shape and vigor. The compact types
When the tip is cut back, some needles must be left on            with many stems are the most desirable. Because of its
the remaining portion or the twig will die back to last           variability, it is more desirable when grown as a single
year’s growth. For further information on pruning, see            plant rather than in masses. Pruning may be necessary
MU publication G 6870, Pruning Ornamental Shrubs.                 to maintain its desirable growth habit. Mugo pine is sus-
      White pine is sensitive to air pollution. Therefore it      ceptible to pine needle scale.
is not a good choice for planting in city conditions.
      Austrian pine (Pinus nigra). The long, stiff needles        Spruce
of Austrian pine are produced in bundles of two. They                  The needle-like foliage of the spruces is four-angled
are a deep, dark green color that makes the plant excel-          in cross section, not flat as with most conifers that pro-
lent to use as a background for small trees with colorful         duce their needles singly.
flowers or ornamental fruit. Austrian pine develops into          Spruces can be recognized
a large tree and needs adequate room for growth (Figure           by the persistent leaf bases
2). It is relatively resistant to air pollutants and will grow    that remain on the twigs
on a wide range of soil types. However, it is susceptible         after the needles have fallen.
to a serious fungal tip blight disease.                                Spruces are native to
      Scotch pine (Pinus sylvestris). Scotch pines can be         cool climates and therefore
recognized by their short, twisted needles that are pro-          are poorly adapted for
duced in bundles of two. They are commonly grown for              growing in most of
Christmas trees (Figure 3). Young trees have a symmet-            Missouri. They should be
rical pyramidal shape, but they develop an open pic-              planted only on well-
turesque growth habit as they mature. Mature speci-               drained soils. Young trees
mens develop a reddish orange flaking bark on upper               are attractive with their
branches. Scotch pines are susceptible to a fatal disease         dense foliage and symmet-

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Figure 5. Colorado blue         Figure 6. Hemlock.                Figure 7. Upright yew.        Figure 8. Arborvitae.

rical growth habit. The four spruces described in the fol-        commonly grown in Missouri.
lowing section are the ones most commonly available in                  Concolor or white fir (Abies concolor). The concolor
the nursery trade.                                                fir is similar to blue spruce in foliage color and general
     Norway spruce (Picea abies). Norway spruce is one            form of the tree. It is adapted to the northern one-third
of the fastest growing of all the spruces. As the tree            of the state. Because of its greater insect and disease
grows older, the side branches become horizontal with             resistance, it may be preferable to blue spruce. We do not
a slight upturn at the tip. Secondary branches hang               generally recommend it for
downward from the main branches, giving the tree a                other regions of the state.
graceful appearance. The large cones (4 to 6 inches long),              Douglas fir (Pseudo-
largest of any of the spruces, are an added attraction in         tsuga Menziesi). Douglas fir
years when they are produced.                                     is not a true fir. It belongs to
     Black Hills spruce (Picea glauca densata). Black Hills       an entirely different genus.
spruce, a slow-growing, compact cultivar, is one of the           A Douglas fir can be most
hardiest of the spruces. Its dense green to bluish green          easily recognized by its long
foliage is its most ornamental character.                         pointed buds and its unique
     Dwarf Alberta spruce (Picea glauca ‘Conica’). The            cones that have a forked,
dwarf Alberta spruce is a miniature conical shaped tree.          papery bract sticking out
It grows very slowly and seldom needs pruning. The                from between the scales.
bright green, dense foliage makes it attractive. Its max-         The flat needles are grooved
imum size under Missouri conditions seldom exceeds 4              on the upper surface with a
to 5 feet. Alberta spruce is primarily a novelty specimen         white band on either side of
plant and seldom is used in basic landscaping. The plant          a      prominent         midrib
is commonly affected by mites, especially when planted            beneath. Douglas fir is not
under eaves, where they are sheltered from rainfall.              adapted to Missouri condi-
     Colorado blue spruce (Picea pungens). The blue               tions except in deep, well-
spruce is one of the strongest accent plants we have              drained soils.
(Figure 5). Because of its stiff growth habit and unusual
color, it stands out wherever it is planted. Placing this tree    Hemlock
in a landscape is difficult because it is so dominant. It is           Hemlock can be recog-
best used as a single specimen for accent. A blue spruce          nized by its short, flat nee-
grows slower than green types and usually commands                dles with narrow white
a higher price. It is one of the most difficult conifers to       stripes on the underside. Its
grow in our soils and climate. It is susceptible to several       small cones are only about
fungal diseaes.                                                   one-half inch long. Only one
                                                                  species of hemlock is com-
Fir                                                               monly grown in Missouri
    The flat needles of firs leave a round, flat scar when        (Figure 6).
they fall from the twig. The cones of firs are borne in an             Canada hemlock (Tsuga canadensis). Hemlock is one
erect position, while those of most other conifers hang           of the most graceful and beautiful of the needled ever-
downward. Concolor fir, described below, is the only fir          green trees, but it needs moist, well-drained soil to

                                                             G 6815                                                     Page 3
develop properly. It prefers partial shade and should be
                                                                Table 1. Approximate mature height of some commonly grown

protected from the wind. It is easy to transplant but
                                                                cultivars of yew.

requires a good soil. Hemlock will withstand close
shearing and is one of the better needled evergreens for
                                                                       Upright cultivars

growing as a hedge.
                                                                          Capitata . . . . . . . . . . . . . . . . . 6 to 8 feet
                                                                          Hicks . . . . . . . . . . . . . . . . . . . 6 to 10 feet
                                                                       Globe-shaped or rounded cultivars
                                                                          Browni . . . . . . . . . . . . . . . . . . 4 to 6 feet
Chamaecyparis, false cypress
    Chamaecyparis, or false cypresses, are variable
                                                                          Halloran . . . . . . . . . . . . . . . . . 3 to 5 feet

evergreens. Both tree and shrub forms are available in
                                                                       Spreading cultivars

a wide variety of foliage colors. They are native to moist
                                                                          Densiformis . . . . . . . . . . . . . . 3 to 4 feet

climates and therefore are not well adapted to Missouri
                                                                          Wardi . . . . . . . . . . . . . . . . . . . 4 to 6 feet

conditions.                                                     Japanese yew (Taxus cuspidata) is the hardiest. Most
    Chamaecyparis should be planted in protected loca-          ornamental cultivars grown in Missouri are forms of the
tions and in limited quantities on a trial basis rather than    intermediate yew (Taxus x media), also known as
as extensive permanent plantings. We do not recom-              Anglojap yew, which is a hybrid of the two species men-
mend them for general landscape use.                            tioned above.
                                                                    The many cultivars of yew can be divided into three
Cedrus — the true cedars                                        groups: upright, globe-shaped and spreading. Upright
     Cedrus, or true cedars, make outstanding landscape         yews are usually less than half as wide as they are tall.
plants where they are hardy. In Missouri, they should           Globe-shaped or rounded ones are about the same
be planted only in protected locations, except in the           width as height. Spreading yews are two to three times
southern third of the state. The needle-like evergreen          as wide as they are tall. Some of the most commonly
foliage of true cedars usually is produced in bunches           grown cultivars are listed in Table 1.
near the terminals of branches. Cones of true cedars are
borne upright on the upper side of branches.                    Arborvitae
     Because the hardier forms of cedrus are relatively              Arborvitae has flat-
slow growing and somewhat difficult to transplant, they         tened, scale-like needles
are not commonly available in nurseries.                        with rounded edges (Figure
                                                                8). Its seed is produced in
Yew                                                             small cones. It is an easily
     Yews are the most popular evergreens being planted         propagated, fast-growing
in Missouri (Figure 7). Their                                   plant that is commonly sold
flattened, needle-like leaves                                   in the spring of the year at
are the darkest green and                                       discount prices. Arborvitae
the most ornamental of all                                      can be injured seriously by
the needled evergreen                                           late spring frosts and by
shrubs. Their fleshy red                                        winter drying. It tends to be
fruit, ability to grow in                                       a relatively short-lived
shade and lack of serious                                       plant.
insect or disease pests also
contribute to their popu-                                       Juniper
larity. Seeds and foliage are                                        Junipers have sharp,
toxic to humans and live-                                       pointed, scale-like foliage.
stock.                                                          Their fruit is a fleshy blue
     The sexes are separate in yews. Male flowers are           berry. The sexes are sepa-
produced on one plant and the female flowers on                 rate, and only female plants
another. Only female plants produce the attractive              produce berries.
berries, but both sexes need to be present to ensure fruit           Junipers are among the
production. One male plant is generally sufficient to pol-      best adapted and hence the
linate six to eight female plants.                              most commonly grown
     Yews will withstand almost any exposure and will           evergreens in Missouri.
grow in any reasonably good garden soil that has good           They withstand hot, dry,
drainage. They prefer a shaded or partially shaded              poor soils better than other
planting site with a moist, well-drained soil. Direct sun-      evergreens. Junipers need
light and strong winds may injure the foliage in winter.        full sun for best develop-
     Among the yews grown as ornamentals, the English           ment. None of the junipers
yew (Taxus baccata) is the most ornamental, but the             will grow on wet, poorly

                                                           G 6815                                                                    Page 4
Figure 9. Creeping juniper.                                            Figure 10. Pfitzer juniper.

drained soil or in heavy shade.                                        approximate sizes of some of the most commonly grown
    There are hundreds of cultivars of juniper from                    cultivars of spreading juniper are shown in Table 3. Most
which to choose; they come in all sizes and shapes. The
color varies from yellow-green to green, blue-green,                   Table 3. The approximate sizes and foliage colors of some

gray-green or silver. Because so many cultivars of
                                                                       spreading cultivars of junipers.

juniper have been grown, many of the names have                                                      Height      Spread            Foliage color
become confused. For landscape purposes we can
                                                                           Cultivar                  (feet)       (feet)

divided them into three major groups: prostrate,                           Compact Pfitzer              3             6                 green

spreading, and upright. The cultivars described here are
                                                                           Blue Pfitzer                 3             6                 blue

the ones most commonly available.
                                                                           Armstrong                    4             6                 blue-green

    The prostrate, or creeping junipers (Figure 9), are
                                                                           Hetz                         8             8                 light blue

low-growing plants used primarily as ground covers.
                                                                           Arcadia                      2             5                 green
                                                                           Old Gold                     3             5                 yellow-green
They seldom grow over 18 inches high and will spread
over a large area. The foliage of many prostrate junipers              spreading junipers retain the same foliage color year-
changes color during winter. The summer and winter                     round.
                                                                           Most upright junipers are actually grown as shrubs.
Table 2. The approximate sizes and foliage colors of some              Unless they are heavily sheared, they will quickly out-
                                                                       grow their intended use. To develop their natural
common prostrate junipers.

                                                                       beauty, they need to be planted where they have plenty
                                                                       of room to grow. The foliage color of most upright
                   Height Spread       Summer        Winter
 Cultivar         (inches) (feet)       color        color
 Andorra              18      5 to 8   light green   plum
 Bar Harbor           10      6 to 8   gray green    slate             Table 4. Foliage colors of some common cultivars of upright
 Blue Chip             8      5 to 8   blue          blue              junipers.
 Blue Rug              6      6 to 8   blue          blue
                                                                           Cultivar                                         Foliage color
 Procumbens           10      6 to 8   blue-green    blue-green
 San Jose             10      6 to 7   gray-green    gray-green            Blue Heaven . . . . . . . . . . . . . . . .powder blue
 Sargent (green)      10      6 to 7   green         green                 Burki . . . . . . . . . . . . . . . . . . . . . .blue
 Sargent (blue)       18      6 to 7   blue          blue                  Canaertii . . . . . . . . . . . . . . . . . . .blue-green
 Turquoise spreader    6      6 to 8   green         green                 Keteleeri . . . . . . . . . . . . . . . . . . .green
                                                                           Wichita Blue . . . . . . . . . . . . . . . . .light blue

foliage colors and sizes of some common prostrate
                                                                           Skyrocket . . . . . . . . . . . . . . . . . . .green

juniper cultivars are given in Table 2.                                junipers does not change with the seasons. Colors of
     Spreading junipers (see Figure 10) can be divided                 some of the most common cultivars are given in Table 4.
into two groups. The first group has a horizontal growth                   Many cultivars of juniper are available in nurseries,
habit that gives the plant a flat-topped appearance.                   and new ones are always being developed. The lists in
Branches on the second type have an arching pattern of                 Tables 2, 3 and 4 are just a few of the more commonly
growth that makes a more vase-shaped plant. The                        available cultivars. You will find many others; some may

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Page 6                                                                  G 6815                                                 Reviewed and reprinted 4/03/7M

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