Winter Hardy Plants for Window Boxes and Containers

Posted on: December 20th, 2012 by Michele Sokoloff

How nice it is to have our outside planters look green and full even during the cold season. It is definitely achievable and not difficult to do. For those of us who want outside window boxes and containers to look nice, neat and well-kept during cold months, here are some plant selection suggestions.

The first step is to clean out and remove the summer/fall-only plants from your pots and boxes. Even if they are left empty, the overall look is much better that the alternative of straggly, droopy, brown remnants of the previous season.

Call up or look up some nurseries and garden supply places not too far from where you live. The following four plants described below have proven to be winter hardy. See if you can locate them.

Dwarf English Boxwood (Buxus sempervirens ‘Suffruticosa’)

A small, rounded shrub that forms tufts of growth resembling a cloud if unsheared. It is ideal for edging and borders. It is well suited to containers. This Boxwood is the most resistant to leaf miner insects.


Cold Hardiness Zones: 5-8. It is an evergreen.

This Plant’s Lore:

A Latin translation for Buxus is ‘box’ and the name may have been derived from its use to make small, finely carved boxes. Buxus is also Latin for flute. It is said that the Roman gardener, Pliny, grew Buxus for making musical instruments. Dating back to 4,000 BC, Egyptians used clipped Boxwood hedges in their gardens. During the reign of Henry VII, it has been written that Tudor gardens featured clipped Boxwood in knot-shaped garden designs with lavender bordering them.

Pieris Japonica (Mountain Fire)

Beautiful fiery red new growth matures to deep green. A prolific producer of broad, drooping, white flower clusters.

mountain_fireCold-Hardy Zones: 5-8. It is an evergreen.

This Pieris is a bold colored plant for partially shaded gardens. It is a great solution for the damp, acidic soil conditions in the Pacific Northwest. Bright foliage color and charming flowers makes it a suitable accent plant for condo and townhouse patios, city gardens and courtyards. Once matured, it can be used as a side-yard privacy screen.


This plant was named in 1834 by David Don. The genus was named after the Pierides or nine muses of mythology. The parent species is P. japonica, introduced in 1784 as Andromeda japonica. It was introduced in England in 1870 as the most cold-hardy of all species.

Dwarf Japanese Garden Juniper (Juniperus procumbens ‘Nana’)

dwarf_juniperThis ground hugging Juniper provides a dense mound of branches that radiate from the center. New growth is bright green turning to bluish green as it matures. Winter color has a purple tint. It is a wonderful groundcover or for group planting on a rocky slope. Foliage and form is best when left unsheared.

Cold Hardy Zones: 4-9. Note: It is deer resistant and pest and disease resistant.


The J. procumbens is native to southern Japan. It’s exact origin is still under dispute. The ‘Nana’ cultivar is probably the most widely grown ornamental and is commonly used in bonsai.

Willow Leaf Cotoneaster (cotoneaster salicifolius)

willow_leafThe vibrant fruit of this spreading semi-evergreen shrub attracts birds. Graceful, arching branches are low-growing and well-suited for ground cover, erosion control or planting in large groups. Very hardy in containers in winter. Prefers well-drained soil.

Cold Hardy Zones: 6-8. Leave fruit on plant for winter interest.


Cotoneaster is a genus of woody shrubs native to Asia, Europe, North Africa, and China. Note: This plant is also commonly known as Chinese Bearberry because bear and deer like to feed on its berries in winter.

There are numerous winter-hardy plants that remain green and look well outside in pots, boxes and containers. You may need to saw or cut off some of the bottom roots to enable the plant to fit into smaller living quarters. You will be pleasantly pleased with the results. Just remember to water, so the soil does not completely dry out.

Written by Michele Sokoloff

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