Shrubs for Tubs
Evergreens in Pots Can Lift Your Winter Spirit.
By Rachel Foster 12/8/05

Now that you have cleared away the frost-nipped, rain-soaked container plants from your patio, balcony or doorstep, is there anything left to look at? Even one winter-resistant pot with something green in it can be a lot better than nothing. Gardening may be less appealing at this time of year, but putting something fresh in a pot to perk up your entryway can be done in the comfort of the garage. While you are at it, why not pot up one or two extras to give away as gifts?
With what seems to be a growing awareness of the potential for year-round containers, garden centers are offering more plants than ever with fall and winter appeal. There are several herbaceous plants that will make it through the winter looking respectable, and some will even bloom, especially with a little shelter from the elements. Evergreen shrubs, though, are the real stars of the winter pot garden, and they add height, substance and background greenery to summer arrangements, too. With that in mind, I like to plant a few things that will, with occasional repotting, live contentedly in pots for several years, growing more imposing over time.
The conventional image of a potted evergreen is neat and formal, but there are many choices for a more relaxed look. Boxwood and bay are classic and both can be clipped or not. If you think you don't like boxwood, check out Korean box (Buxus microphylla): the same small, glossy leaves on a looser grower, almost impossible to discipline into a ball. Camellias and bay trees are great for larger spaces. Big ones are expensive, but you can, of course, raise your own from a pup. Evergreen privet and super-dark green Portugal laurel are other options for a really big tub plant.
Coniferous evergreens come in a huge range of shapes and foliage colors. Blue Lawson false cypress, gray columnar junipers and Italian cypress, green or gold, are all naturally upright and formal. Arbor vitae are a bright and cheerful green and relatively inexpensive in large sizes. Spruces are stiff, prickly and mostly pyramidal, great for supporting a string of lights. Pines and Hinoki false cypress are less formal in structure, and just about everything I've mentioned has squatter, bun-shaped variants for contrast. Cruise a few nurseries and see what suits your purpose. Bloomers is especially good for this, stocking many evergreens in a range of sizes.
A big, vigorous grower confined to a tub will demand frequent food and water and regular re-potting or root-pruning to keep it looking good. Naturally small plants and dwarf varieties are a little easier to maintain. Some plants are such demure growers that you can leave them undisturbed in the same pot for years, pruning lightly and feeding sparingly. Drimys (or Tasmannia) lanceolata, available from Bloomers Nursery, has small, dark green, leathery leaves on attractive red stems and petioles. I love this little Aussie shrub for its tolerance of drought and a wide range of light conditions.
I've had a compact version of true myrtle (Myrtus communis 'Tarantina') in a pot on my deck for several years. Spring pruning removes winter-damaged foliage and produces a flush of new growth that bears adorable fuzzy white flowers from midsummer onward. Like bay, this is a Mediterranean shrub that appreciates the protection of a spot near the house. Other non-coniferous alternatives include hebe and evergreen daphnes such as Daphne retusa, currently available from Down to Earth. Be careful not to over-water it!
Use weather-proof pots and tubs for shrubs that you plan to keep outside year round: oak wine barrels, redwood or cedar tubs, concrete or glazed ceramic pots all last for years outdoors. Whatever the container, ensure it has adequate drainage holes, and don't place it directly on soil, where ice may block the holes. Start with a container that is not too big for the plant: a well rooted, one gallon nursery plant can go in a 2 or 3 gallon pot, but might become waterlogged in a pot much bigger than that. Re-pot every one to two years, either moving up to a bigger pot or shaving off enough of the root mass to fit in the old pot with room all around for new soil. I usually do this in spring.