Joe’s Journal, Winter Edition: Planting Trees into the Landscape Garden, part I

In this two part series, I’ll get into what kinds of trees you should consider for your landscape and garden. You may not necessarily plant trees yourself, and most likely will have a landscape nursery create a planting plan for you. Even so, you ought to have an appreciation of the basics of landscape gardening. Being informed about the plant’s different needs, like sun/shade requirements and spacing, will ensure you have a healthier landscape!

Let’s start with ten trees to consider for planting, which will make up our planting palette:

  • American elm
  • Corkscrew willow
  • Crabapple
  • Eastern white pine
  • Freeman maple
  • Green Giant arborvitae
  • Sugar maple
  • Swamp white oak
  • Weeping European beech
  • Weeping willow

The plantings you are most likely to be familiar with are planting a shade tree as a specimen plant, and hedge and border plantings. These are typical of the residential landscape today, but there are many options to consider besides replicating how a plant looks in its natural environment.

Consider for examples, themed gardens such as the Asian Garden, Butterfly Garden, Cottage Garden, Cutting Garden, the Edible Garden, the English Garden, the Native Garden, the Pollinator Garden, the Shade Garden, the Water Garden and the Winter Garden!

Specimen Tree Planting

Let’s start with the very basics: the specimen tree and the hedge. Specimen trees are featured in a lawn with plenty of room to develop its full form. If you are fortunate to live in the central and eastern US, then you might consider the Sugar maple (Acer saccharum), for fall color alone. It develops brilliant shades of red, burgundy, orange, and yellow in the fall. Give this tree room to grow. It can get 50 to 120 feet tall with a dense, spreading crown of 30 to 60 ft. It needs a site with full sun (for best fall color), good drainage and soils with plenty of organic matter. It grows best in soils with a pH of between 6.0 and 8.0.  However, if short on space, consider planting a crabapple.

Sugar maple
Sugar maple

Crabapples typically grow 15 to 26 feet in height, with a spread of 10 to 20 feet. Crabapples are grown for their spring bloom. Flowers are pink, purple lavender, red/burgundy or white. They are prone to pests and disease, including caterpillars that feed on foliage and scab that can defoliate the tree by summer. Select a cultivar that is apple scab resistant to avoid annual spraying. Although it attracts caterpillars that feed on the foliage, it will also attract songbirds that feed on caterpillars.

Fig. 2 Flowering crabapple (2)

If you are on a lowland, wet site, consider the American elm (Ulmus americana) or the Swamp white oak (Quercus bicolor). The American elm is an iconic native tree that will grow 60 to 80 feet in height with a 30 to 60 feet spread. The beauty of the tree is its form: it has either arching, erect, spreading, or a vase-shaped habit. It is a fast-growing tree, but the native species is susceptible to Dutch elm disease (DED), a vascular wilt that all but decimated the tree. It is also susceptible to phloem necrosis, incited by a phytoplasma, which is also lethal. Fortunately, this disease occurs rarely. DED resistant cultivars include: Delaware #2, Jefferson, Liberty, New Harmony, Princeton, and Valley Forge.

Princeton elm
Princeton elm

Swamp white oak is a native, medium sized tree growing 50-60 feet high and wide. With age, it develops a broad, oval crown. The species epithet (‘bicolor’) refers to both its bark and leaf. The leaves of the tree have rounded lobes much like white oak, but glossy green above, and silver-white below. The bark is exfoliating, peeling, gray to dark brown. The leaves turn copper, gold or red/burgundy in the fall. If space is limiting, then you may consider the corkscrew willow (Salix babylonica var. tortuosa).

Swamp white oak
Swamp white oak

Corkscrew willow grows best in full sun in moist soils. It will grow 20 to 40 feet in height with a width of 15 to 25 feet. It has interesting contorted branches that are often cut for dried arrangements. It is susceptible to branch cankers. It is a short-lived tree, but easily propagated by cuttings.

Corkscrew willow
Corkscrew willow

The Hedge or Border Planting

Both deciduous and evergreen trees may be used in the border for privacy screening. The advantage of an evergreen hedge is that it provides privacy year-round. The two species considered here are the Green Giant arborvitae (Thuja standishii x plicata), a hybrid evergreen, and the eastern white pine (Pinus strobus), a native tree.

The Green Giant arborvitae is a large, woody evergreen in the Cypress family. It is best planted in moist soil, in full sun to part shade. It is resistant to most diseases, periodic droughts, and deer. However, it is intolerant to salt spray, including winter deicing salt. It forms a dense, columnar-pyramidal habit. It is a fast-growing tree and can grow 3-4 feet per year with a spread of 12-18 feet. The dark green glossy scale-like needles occur in sprays that give the tree textural interest in the landscape. It is a good alternative to Leyland cypress in the southeast. Give it plenty of room to grow, spacing 12-14 ft. apart. The Green Giant arborvitae attracts songbirds, resists deer, drought, insects, and wind.

Green giant arborvitae
Green giant arborvitae

The Eastern white pine is native to central and eastern US. An evergreen conifer, it will get to 50-80 feet tall with a spread of 20-40 feet. It is tolerant of a wide range of soil conditions, but prefers full sun to part shade in moist, well drained and fertile soils. It grows best in cool and humid climates. White pine is intolerant of pollutants, including sulfur dioxide, ozone, and alkaline soils. Needles are soft, bluish-green, and fragrant. It is susceptible to several diseases and pests, including:

  • Blights
  • Canker
  • Rusts
  • White pine weevil
  • Bark beetles
  • White pine shoot borer
  • Zimmerman moth larvae
  • Pine sawfly
  • Scale
  • Aphids.

It is a wildlife food source! It forms a conical, pyramidal, oval tree when mature, but lends itself to shearing. Its rapid growth rate makes it a good choice for a privacy screen. Space 24 to 60 feet apart. It is resistant to deer and rabbits.

Eastern white pine
Eastern white pine

Next time we will consider trees to plant in the Asian Garden, Butterfly Garden, Cottage Garden, Cutting Garden, the Edible Garden, the English Garden, the Native Garden, the Pollinator Garden, the Shade Garden, the Water Garden, and the Winter Garden!