No garden is complete without at least a few containers for seasonal color. I always specify locations for planters when I create a new landscape design, with the intention of keeping them filled in every season. Although many gardeners keep their containers filled with annuals in summer and cut greenery in winter, there is another option. Planting a dwarf evergreen that can remain in its pot for several seasons will provide structure and texture every month of the year.
When choosing an evergreen shrub or tree for an outdoor planter, look for cultivars that are hardy one zone colder than your area. In other words, if you live in Zone 5, your selection should be hardy to Zone 4 or below. Growing conditions for plants in a container are harsher than they are for plants in the ground, so additional resilience is necessary.
Your next decisions are aesthetic: Are you looking for something tall and formal, low and spreading, or something entirely different? Here are a few options to get your search started.
Boxwoods look formal and tidy
If you need a plant that is easy to manage and has a classic look, a boxwood (Buxus spp. and cvs., Zones 4–9) is a perfect choice. My two favorites are ‘Green Velvet’, which has a globe form, and ‘Green Mountain’ (pictured), which has a loosely pyramidal form. Having used these almost exclusively for over 20 years, I can attest to their hardiness and resilience in containers. Among the most commonly used evergreens for containers, boxwoods lend themselves to being pruned to almost any shape or size, or they can be left in their natural form. A coat of anti-desiccant spray applied in early winter will help reduce foliar damage and dehydration.
For cool, silvery color, choose a dwarf blue spruce
If you’d like to to add some cool silvery-blue color to your containers, dwarf spruces offer many attractive options. ‘Glauca Globosa’ blue spruce (Picea pungens ‘Glauca Globosa’, Zones 2–8) makes a bold statement in a large container, perhaps even more dramatic than when it is planted in the ground. Elevated by a pot, the blue foliage becomes a sculptural statement, and the tree’s ability to be moved around your garden spaces is a bonus. Moderate to slow growing, it can remain happy in the same pot for many years.
A dwarf Mugo pine delivers big texture in a small package
Striking and ornamental, pines are available in a diverse variety of forms. ‘Sherwood Compact’ mugo pine (Pinus mugo ‘Sherwood Compact’, Zones 2–7) is a dwarf variety that stays under 3 feet tall and wide, making it perfect for anchoring a container design. This exceptionally hardy and compact mugo pine is perfect for a container in full sun. Strategic spring candle pruning can be used if you prefer to keep its compact form even more condensed.
Whichever selection you make, adding evergreens to your containers will transform your garden by extending its beauty into every season.
- For more plant selections and information on how to plant conifers in containers, check out How to Grow Conifers in Containers from Fine Gardening issue 202
- Check out our entire Container Gardening Project Guide
- For an article about how to design with dwarf confers, click here.
For more Midwest regional reports, click here.
Marti Neely, FAPLD, owns and operates Marti Neely Design and Associates in Omaha, Nebraska.