Redoing container plantings has always been a recurring task in my garden. Recently, however, I’ve realized that it’s easy to choose plants that look fabulous all year long. Adding year-round potted pleasures to the garden not only makes my work as a gardener easier, it also helps me refine the “bones” of the garden by adding strong focal points and year round color. There’s a perfect plant for every location.
Boxwood (Buxus spp.)
Few plants evoke southern gardening traditions as strongly as boxwood. Boxwood have tiny green leaves that look the same throughout the year. Most cultivars grow slowly and will thrive in full sun or partial shade; they are very low maintenance and generally hardy in Zones 4-9.
Small cultivars, ranging in size from 1-5 feet high and 2-4 feet wide, are perfect choices. Plant them in pots that are at least as tall and wide as the plant and choose a location that provides some protection from harsh winter wind. Boxwood require a loamy potting soil that drains well. They should be watered regularly, especially during hot, dry summer months. Boxwood benefit from the addition of several inches of compost to the top of their potting soil every spring. Since boxwood are shallow rooted, other plants shouldn’t be added to their containers.
Three interesting ones to consider are ‘Glencoe’, a hybrid selected by the Chicago Botanic Garden for use in containers; ‘Green Mound’, a globe-shaped hybrid; and ‘Green Mountain’, a hybrid with a pyramidal shape that adds an interesting sculptural element to the garden.
Boxwood are a traditional choice for containers in most gardens.
If you’re looking for a plant to add architectural interest and drama to a container planting, then Yucca is an excellent choice. Y. filamentosa has upright, sword-shaped leaves that are edged with curly “hairs.” There are both green and bicolored varieties.
Yucca prefer full sun to partial sun and are highly tolerant of heat, humidity, and drought. To avoid root rot in winter, plant them in a loose soil that drains well. Hardiness varies by species and cultivar. Yucca look lovely planted alone in a wide, shallow, bowl-shaped container.
There are several bicolor yuccas that are especially dramatic in containers and are medium sized (2-3 feet tall and equally wide). Both Y. filamentosa ‘Color Guard’ and ‘Wilder’s Wonderful’ have leaves with creamy golden centers and green edges. The leaf edges of ‘Wilder’s Wonderful’ have a bluish tint.
Yucca can add instant architectural interest to the garden.
Sedum are a group of succulents known for their colorful, fleshy foliage and ease of culture. They prefer well-drained soil and full to nearly full sun. They are generally hardy in USDA Zones 4-9. Once established, they require infrequent watering. The low-growing, creeping varieties are perfect for small accent containers and as companion plants in larger pots. Try planting sedum in groups of differently sized hypertufa pots. For more textural interest, add a large pot of moss.
Some Sedum develop interesting coloration during winter. Try S. spurium ‘Tricolor’, a low-growing creeper with pale green leaves edged with white. In winter, the leaves become pinkish. S. rupestre ‘Angelina' is another creeping variety with chartreuse needle-like foliage that turns orange in winter.
Slow-growing dwarf or miniature conifers are available in a variety of colors and shapes. Pyramids, globes, and irregular weeping forms can be found with green, blue-green, and yellow foliage. Dwarf conifers grow 1-6 inches annually; miniatures grow less than an inch annually. Growth habits range from compact to loose and open. Most dwarf and miniature conifers need moist, well-drained soil with lots of organic matter. They can be grown in sun to partial sun; they should be watered regularly and given some protection during periods of extreme cold. Most are hardy in USDA Zones 4-7 or higher.
Dwarf and miniature conifers generally don’t need extensive root space, so they can be planted in wide saucer-shaped bowls or troughs. Containers of conifers are striking when used as a solitary specimen near gates or grouped along a path to highlight different growth habits. Chamaecyporisobtusa ‘Nana Gracilis’ is a dwarf hinoki cypress with an irregular upright habit; C. obtusa ‘Ellie B’ is a miniature. Low-maintenance Picea glauca var. albertiana ‘Conica’ is a dwarf Alberta spruce with a compact, pyramidal growth habit and dense needles. It can be pruned as a topiary. Thuja occidentalis aurea ‘Golden’ has a very small globe shape with golden foliage.
Heuchera are low-growing, mounding plants with ruffled, heart-shaped leaves. They’re grown primarily for their colorful foliage and are available in a variety of colors – purple, burgundy with silver venation, chartreuse, and bronze. Most Heuchera prefer full to partial shade, but some newer caramel-colored cultivars can withstand more exposure to sun. They are hardy in USDA Zones 4-9. Plant Heuchera in rich, well-drained soil.
Heuchera can be used alone in medium-sized pots or as companions with other potted plants. They are excellent choices for adding interesting colors to winter gardens. ‘Paprika’ has bright coral to orange foliage and can withstand full sun. ‘Velvet Night’ changes color with the seasons – red in spring, taupe in summer, and ruby red in fall. It tolerates heat, humidity and some drought. ‘Ginger Peach’ is a rapid grower with large amber ruffled leaves. It tolerates full sun and will quickly fill a container.
There are so many ways to design container combinations that look lovely year round and so many plants to consider. While there’s nothing more traditional or striking than an arrangement of containers of various sizes planted with boxwood near the entrance to a home, don’t forget nontraditional choices. Not interested in conifers or yucca? Then make a simple pot of moss, perhaps the most elegant choice of all. Consider the fleshy, prickly holly fern (Cyrtomium falcatum ‘Rochfordianum’), maybe even a hardy palm. Experiment and discover the beauty of year round container gardens.
Holly fern is an evergreen variety that combines nicely with pansies for additional color in fall, winter, and spring.
Container size: Choose an attractive container that is large enough to allow for growth and is the right shape. Some plants require deep containers, while others grow well in wide, shallow ones. Drainage is also important, so be sure that the container has drainage holes.
Container durability: Choose containers that can withstand winter cold and summer heat without cracking. Line the inside of the pot with bubble wrap for extra protection for the pot and plant.
Potting soil: Select a potting soil that is appropriate for each plant. Repot the plant and replace the soil after three to four years, if necessary.
Moisture: Container gardens require frequent watering, especially during hot summer months and again during early winter. Continue watering container plants until the soil is frozen.
Plant: Review the growing conditions for the plants you’re considering – full sun, partial sun, shade, etc. Make sure that the plants you choose are hardy in your area. Remember that pots won’t completely protect a plant’s roots from the cold. Avoid selecting a plant that requires a lot of attention. Look for plants that are particularly suitable for growing in pots.
Location: The right plant in the right pot in the best location in the garden. It’s always best to determine the location before filling the pot.
Consider leaving billowing dead grasses in pots all winter; just cut them back in early spring before they break dormancy.
A version of this article appeared in a March 2016 print edition of State-by-State Gardening. Photography courtesy of Cynthia Wood.