Containerized Trees: Small Spaced Landscaping / Big Effects

Part Two: The Right Tree in the Right Place with the Right Care

By Elizabeth Cornell Fake, Fairfax Master Gardener
Part One of this two-part series gave an overview of the importance of site and choice of container for planting a containerized tree. Part Two continues the discussion with pointers on tree selection, tips on planting and guidelines for maintenance.

Tree Selection
Think of a containerized tree the same way you would when adding a tree to your landscape. The same requirements for sunlight exposure and moisture apply. If you can plant it outside, then you should be able to grow it in a container. The chart below identifies some hardy candidates for a containerized tree.

Type Options Special Considerations
Citrus Lemon,Lime, Kumquat, Orange and Tangerine Frost tender. In winter, move inside or to greenhouse
Fig Edible Fig (Ficus carica) Requires consistent Zone 7 climate for outside growth
Plan to move inside for winter
Japanese
Maples
(Acer palmatum)
Spectacular fall foliage
Requires large container for root development
Locate in area with both full sun and shade
Olive European Olive (Olea europaea)
Choose fruitless variety
to avoid oily fruit cleanup
Requires consistent Zone 7 climate for outside growth
Plan to move inside for winter
Prune regularly to limit height
Privet Good selection for topiary treatment
(Ligustrum spp.)
Grows prolifically and can be invasive
Prune regularly
Southern
Magnolia
Good choice for balcony tree.
(Magnolia grandiflora)
Requires very large container and sufficient
vertical space (10 feet) to grow
Requires consistent Zone 7 climate
Sweet Bay Produces culinary bay leaves
(Laurus nobilis)
Requires full sun to partial shade
Bring indoors in winter
Witch Hazel Dependable late winter/early spring
flowering tree (Hamamelis spp)
Grows well outside in Virginia year-round
with full sun to part shade
Prune regularly to maintain height

Planting
Before planting, take a few minutes to think about what you are going to do. To make sure you plant the tree at the correct depth, look at the trunk to find the root flare. This is the place where the trunk meets the root base. Using the trunk flare as the baseline for planting, plant the tree so the trunk is level with the soil and the roots are covered. Now look at the commercial packaging provided for the tree. Remove any synthetic or plastic wrapping and cut away wire and twine wrapped around the trunk. Natural burlap can remain in place as it will biodegrade. Examine the root ball to check for circling roots. Open the root ball and pull roots firmly into an outward position. At this point, quickly move the tree to the container to keep roots from drying out. Add enough soil to determine the proper height. Then fill in the rest of the container with soil, making sure the tree is firmly in place. Water thoroughly until the water runs out of the drainage holes.

Maintenance
Provide maintenance for the tree following specific grower guidelines. Water only as needed and avoid over-watering. Test the soil surface to make sure it is thoroughly dry to a depth of 1 inch before adding more water. Water completely until excess runs out through the drainage holes.  Fertilize as required for the specific trees, using a water-soluble fertilizer according to package directions. If the leaves are green and glossy, the tree is adequately nourished. Pruning is an essential part of maintaining containerized trees. Plan to prune at least once a year to prevent the root system from exceeding the capacity of the container.

Growing containerized trees can be interesting and fun. Just follow the guidelines for site, container and tree selection, plant carefully and maintain regularly. You will be delighted for years.

Resources
Trees for Landscape Containers and Planters, Bonnie Appleton et al, Cooperative Extension,
   Publication 430-023
Growing Fruit Crops in Containers, Jeffrey G. Williamson, University of Florida IFAS Extension,
   Publication # HS57
10 Top Trees to Grow in Containers, Lauren Dunec Hoang, April 9, 2018
Growing Trees in Containers, Ellen Zachos, National Gardening Association, Learning Library

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