Planting Low-Maintenance Containers -July 2017
by: Hilary Newell
There’s no getting around the fact that one has to have some time and be prepared to work in order to create beauty in and around the home. While I can’t help you find the time portion of that equation,I ca’t help you find the time portion of that equation,I can share some ideas on reducing the amount of work necessary.
We still have a large perennial border, but in order to decrease the number of hours spent doing maintenance, we have increased the number of flowering shrubs and decreased the quantity of perennials. We’ve also shifted quite a bit of the in-ground gardening, mostly flowering annuals, to container gardens. This has dramatically reduced the amount and the intensity of work required to have a beautiful garden. The biggest benefit here is no weeding. There’s also a lot less bending over when the flowering pots are placed on a raised deck that we can reach from ground level.
There’s been so much written about how to choose containers, but there are three basic things that I take into consideration when choosing vessels for plants.
• Drainage is imperative.
• Bigger is better, to reducing watering.
• If you are growing food, use untreated wood, ceramic, terra cotta, plastic, fabric or metal, so no questionable chemicals can leach into the roots.
One of the best ways to reduce maintenance on your containers is to plant something with year-round interest. A single evergreen shrub can look nice all year-round, and choosing something with an interesting texture is a bonus.
Thuja occidentalis, Arborvitae Emerald, is a perfect example of this. Hardy in zones 2-7, Emerald holds its rich green color even in winter. It presents narrow and upright, giving a cool vertical accent. Planted in the ground, it will grow to 15 feet, but being planted in a container checks its growth and it will stay well under that size. Planted in a large container with room around the edge allows you to plant interesting annuals each summer if you desire. This particular plant does well in bright sun or part shade. You might consider sev-
eral of them in a row along an otherwise bare wall. There are lots of dwarf evergreens like Juniper Midget or Juniper Blue Star that look nice in yearround containers.
Another shrub that does well in a large container is Pieris japonica, also known as andromeda, and is sometimes called lily of the valley bush. Many notable cultivars like Mountain Snow and Mountain Fire have been developed that offer year-round interest. Spring growth is eye-catching, with colors from glossy red to ivory white to salmon pink, depending on the cultivar. It is also deer-resistant.
This shrub holds its flower buds all winter and allows them to gracefully open into cascades of slightly-fragrant white blossoms. Arching branches spill over the edges of the pot when you choose a compact variety like Cavatine which will grow happily for several years in a pot. Set your Pieris pot in partial shade, protect it from harsh winter winds, water it when it’s dry and fertilize it once a month from
spring until September for a simple, very-low-maintenance container.
I would be remiss if I didn’t mention that any container that is planted for year-round enjoyment should be frost-proof.
Variegated red-twig dogwood Cornus alba Elegantissima is a vigorous deciduous shrub that provides a long season of interest in the garden. Green and white foliage in summer gives way to white berries tinged with green or blue, apricot/gold/red fall foliage. But in winter, Elegantissima puts on a whole different show, with bright red stems and twigs that are particularly striking under snow. Keep your dogwood pot in a full-sun spot and trim off old wood each fall. The brightest color is on the younger branches.
I have been eyeing Acer palmatum (Japanese maple) lately with a view toward having one in a large planter. The one I’m looking at in particular is long-lived Shirazz. Its bright-pink foliage in spring turns green with creamy pink edges throughout summer. If you’re planting an Acer in a container, be sure to choose one that is labeled “dwarf” or you may end up with a specimen that is way too big. Dwarfs are typically three to six feet tall, are bushy shrubs with small leaves, and are slow-growing: all perfect traits for a container planting.
One of the first shrubs I ever learned was Corylus avellana Contorta, or Harry Lauder’s walking stick. Actually a sport from a filbert tree, this plant was named for the cane carried by the sidekick of Sir Harry Lauder, a famous song-and-dance man from the early 20th century. The contorted branches and shiny brown bark are best experienced in winter, when the shrub has lost its leaves. At a height of four to six feet in the ground, a container will check that growth at about four feet.
Breeders have done a tremendous amount of work with hydrangeas in the last decade, introducing cultivars that not only have more blooms, but hold their blooms for a very long time. There’s a series of big-leaf hydrangeas called Cityline with a compact habit, super-strong stems and incredibly-bright flowers that make them perfect for containers. They grow only to two feet tall and pruning is not needed, so there’s no chance you will cut off the buds. Cityline Mars has unique, two-toned flowers resembling violets, Cityline Paris has vivid near-red florets, Cityline Rio and Vienna are both blue, and like their larger cousins, respond to pH adjustments to intensify their color. Easy to apply, organic pH changers are available in most garden centers. Bonus: the breeders have been able to make these plants more resistant to mildew. That’s excellent news for growing in our very humid conditions.
Most panicle hydrangeas reach six to eight feet tall, making them unfit for container life, but Bobo grows only to three feet tall. Super-lacy flowers start out white and fade to a delicate pink with time. Contradicting the size of the plant, the flowers can reach the size of a football. Hardy from zones 3-9, these plants are easy to work into any container garden or landscape. Hydrangea Limelight in tree form makes a stunning container plant, holding its cone-shaped flowers for months after they first appear. Flowers start out as clean celadon green, and fade to pink, red and burgundy, even lasting through frost. My advice is to get two of these, as they make fantastic cut flowers, and you will want one to look at in the yard, and one to cut for bouquets.
There’s one more hydrangea series I can recom-
mend for containers. Let’s Dance Starlight and Big Easy are two macrophylla, or large-leaf varieties from Proven Winners. Big Easy has extra-large, vivid pink mop-head type flowers that bloom on both old and new wood, meaning they will rebloom later in summer after the initial June bloom period. Starlight is a vividly-colored blue reblooming lace-cap type. Go ahead and prune off the spent blossoms on this series, as they will bloom again on the new, summer growth.
Planting shrubs in containers will provide you with just about the lowest-maintenance, threeto four-season planters you can achieve. But what if you want a little more variety and color? If you don’t mind giving up winter interest, longblooming perennials and certain annuals are a really good answer. I’m referring to tropical plants that are not winter-hardy here.
Plants like bougainvillea, citrus, mandevilla, hibiscus and thunbergia may be perennial in warm climates like zone 10, but will succumb to frost further north. Mandevilla has been popular in southern latitudes for decades, and is a relative newcomer to northern gardens. These gorgeous red-, pinkor white-blossomed viney shrubs are actually quite tough, given their tropical nature. They will grow very well in windy conditions, making them perfect for gardens with full exposure to ocean breezes. It may look delicate, but mandevilla is a strong plant that adds tropical flair to your planting. Set them in bright, indirect light, as they can get burned in full direct sun, so be sure they are shaded from mid-day sun. Feed regularly once every two weeks, and you’ll be rewarded with plenty of flowers. Pinch a quarterto a half-inch off the end of each stem early in the growing season, and the number of flowers will increase.
If you are a fan of roses, but don’t have the room for a rose garden, try one or two in a decorative pot. Roses planted in urns or grown as topiaries lend a sophisticated touch and can provide a lot of color with a minimal amount of labor. Roses in pots can be grown in very small outside spaces, and you can set one or two near walkways or areas that you walk by frequently. Group several roses of different heights and habits for a focal feature in your yard.
David Austin Roses feature a lot of named varieties that are great for containers. Many of their shrub roses have spectacular scents, ranging from bourbon to vanilla to sweet to lemony. Choose a color you like and let the scent come along for the ride. Then when they bloom, be sure to stop to actually smell them. Today’s Knock-Out roses (blush, pink, coral, red or white) are probably the best constant bloomers and make great container plants when kept trimmed.
Ornamental grasses have enjoyed a new popularity in recent years, with old varieties getting makeovers, and new varieties being introduced. Grasses work particularly well when planted as the only thing in the pot. This monoculture sets them off as beautiful specimens, and in the case of aggressive varieties, keeps them in check so they don’t spread to other parts of the garden where they may not be welcome.
Start with one large or several small plants to get a full pot without waiting. Some favorites are mounding Festuca Elijah Blue and some of the smaller Phormiums (New Zealand flax). These are colorful and spiky and will really draw your eye. Some others to try are diminutive Isolepsis (fiber optic grass), whose tiny flowers appear to be lights at the end of each long leaf. There are also plenty of interesting Miscanthus cultivars whose magic lies in backlighting and super-appealing flower heads.
You may want to have containers outside for only three seasons, but if you are keeping planted containers outside over the winter, there are some important things to remember. Stop watering when plants go dormant, when the leaves turn color or just fall off. If the plants do not go dormant, continue to water, but drastically reduce watering as temperatures fall, stopping completely before the soil freezes in the pot. Stop fertilizing by September to prevent new soft growth that could be damaged during the winter.
Plan on repotting every two to three years, depending on the rate of growth. And if your container starts to need water very frequently, it is probably root bound, and needs to be root pruned or put into a larger pot.
Container gardening can be very satisfying and will add points of interest no matter what time of year. ///
Hilary Newell is the marketing director at Bartlett’s Ocean View Farm and a regular contributor to Nantucket Today.