Recommended Trees and Shrubs for Outdoor Container Plantings

The most important criteria for selecting plants for outdoor containers are: (i) hardiness for site: (ii) suitability of growth habit for container size and shape; and (iii) features that give the plant particular year-round or seasonal interest or usefulness.

Trees and shrubs that are kept outdoors in containers are exposed to a wide - and rapidly changing - range of environmental extremes. In comparison to in-ground plantings, the root systems of container plants are more exposed to winter freezing - thawing cycles, hot summer temperatures, and drying out of the rootball soil. Therefore, only very hardy trees and shrubs should be used for year-round, outdoor container plantings. In addition, larger containers 18" minimum, preferably larger, provide more soil mass, water retention, and temperature insulation; therefore, provide more soil mass, water conditions for plants. 

The most suitable trees and shrubs for container plantings also have growth rates and habits that allow them to be kept reasonably "under control" and in scale with their containers and surroundings. In addition, plant features such as branch structure leaf texture and color, and seasonal flowers or fruit should all be taken into account in deciding whether the plant is appropriate for the location.

The following list is not exhaustive, but does include many of the best and most dependable trees and shrubs for container planting. Plants that prefer sun are marked with a single asterisk (*); plants that prefer shade are marked with a double asterisk (**). Most plant varieties can be planted safely in spring, summer or early fall; plants that can also be safely planted later in the fall are marked with an "F'. For a more complete description of hardy woody plants and perennials suitable for containers, please refer to Linda Yang's excellent boot, The City Gardener's Handbook (Random House 1990) (esp. Chapters 4 and 7).

The following list of suggested container plants is organized by plant category, and varieties are listed within each category by alphabetical order of botanical name:

• Weeping Blue Atlas Cedar * (Cedrus atlantica 'Glauca')
• Compact Hinoki Cypress - and dwarf varieties */** (Chaemacyparis obtusa 'Compacta')
• Juniper - all varieties * F (Juniperus)
• Spruce - dwarf and weeping varieties * F (Picea)
• Pine - dwarf and weeping varieties * F (Pinus)
• Japanese Yews */** F (Taxus cuspidata varieties)
• Hybrid Yews */** F (Taxus x media varieties)
• Arborvitae */** F (Thuja occidentalis varieties, esp. compact types)

• Newport Blue Boxwood */** (Buxus sempervirens 'Newport Blue')
• Cotoneaster * (esp. C. dammeri and C. horizontalis cvs.)
• China Girl/Boy Holly */** (Ilex cornuta hybrids)
• Blue Hollies */** (Ilex x mersevae varieties)
• Firethorn * (Pyracantha - all varieties)

• Flowering Hawthorns * F (Crataegus species)
• Magnolia * (esp. smaller hybrid varieties)
• Flowering Crabapples * F (esp. compacr Malus varieties, incl. Sargents, Red Jade)
• Flowering Pear * F (Pyrus calleryana varieties)
• Japanese Pagoda Trees * F (Styphnolobium japonicum)

• Hybrid Flowering Quince * F (Chaenomeles Hybrids)
• Shrub Dogwoods * F (Cornus alba and sericea varieties)
• Harry Lauder's Walking Stick * F (Corylus Avellana "Contorta')
• Russian Olive * F (Eleagnus angustifolia)
• Bellflower */** (Enkianthus campanulatus)
• Rose of Sharon * (Hibiscus syriacus)
• Sea Buckthorn * (Hippophae chamnoides)
• Bayberry * (Myrica pensylvanica)
• Cinquefoil * F (Pontentilla varieties)
• Spirea - esp. compact varieties * F
• Dwarf Korean Lilac * F (Syringa palibiniana) (Syringa 'Masskin')
• Fragrant Viburum * F (Viburnum x Juddii)
• Dwarf Weigela varieties * (Weigela florida cultivars)
• Yucca or Adam's Needle * (Yucca filamentosa varieties)

• Japanese Maple */** F (Acer palmatum varieties)
• Young's Weeping Birch * (Bertula pendula 'Youngii')
• Maidenhair Tree * (Ginko biloba)
• Honey Locust varieties * F ( Gleditsia triacanthos cvs.)
• Flowering Callery Pear * (Pyrus calleryana varieties)
• European Linden * F (Tilia cordata)
• Japanese Keaki Tree * F (Zelkova serrata cvs.)

• Trumpet Vine * F (Campsis radicans)
• Hardy English Ivy Cultivers ** (Hedera helix cvs.)
• Honeysuckle * (Lonicera Heckrotti)
• Wisteria varieties * F (W. sinensis and floribunda)

Need support and regular pruning to restrict size.

• Flowering Carpet Roses
• Meidiland Roses esp. 'Bonica' * F, 'White Meidiland' * F, 'Scarlet Meidiland' * F
• Old Fashioned Shrub Roses - compact varieties * (including "Sea Foam', 'The Fairy')
• Rock Rose varieties * F (Rosa rugosa and hybrids)
• Hardier Climbing Roses (e.g. New Dawn, White Dawn, Cllimbing Iceberg)

• Astilbe species and hybrids **
• Chrysanthemums species and hybrids *
• Coreopsis species and hybrids *
• Daylily (Hemerocallis) varieties * F
• Hosta varieties **
• Sedum varieties * F

• Sedge Grass * (Carex varieties)
• Blue Fescue (Festuca glauca)
• Blue Oat Grass (Helictotrichon and Sempervirens)
• Fountain Grass (Pennisetum varieties)

• All hardy varieties