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Containing the season’s enthusiasm

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Containers of mixed perennials offer colour on a deck. Photo: Jodi DeLong

Containers of mixed perennials offer colour on a deck. Photo: Jodi DeLong

Keeping the planter colour and interest going well into winter

Autumn sneaks up on us. 

The days get shorter, the sun rises later and sets earlier. The air is gloriously warm most days, and cooler at night. The vegetable garden has been profuse, and we’ve canned, frozen, dehydrated, and enjoyed its bounty. There’s still some bloom and colour from perennials, shrubs, grasses and some annuals. Yet, many aren’t ready to stop enjoying our gardens, both in-ground and in containers. 

The answer? Refresh your container plantings. If you’ve been deadheading, cutting back, and fertilizing faithfully, you still have plants in bloom. But sometimes we get busy, and the petunias get leggy, and the million bells are down to dozen-bells, and some annuals have set seed and given up. Come that first frost, tender annuals like nasturtiums will turn to compost. Time to refresh and enhance with other choices that will last through the fall—and even beyond.

Container planting 101

There are three main components for container planting: thrillers, spillers, and fillers, and you can use these throughout the gardening season, with a little modification according to time of year.

Thrillers are the eye-catching plants like canna lily, dahlia, ornamental millet, gaura, or any other showy plant—taller than many, and with that wow factor.

Spillers are the cascading types of plants: trailing verbenas, lobelias, petunias, thunbergia (brown-eyed Susan vine), calibrachoas, portulaca, among others. These create a vertical downward look, or you can train them to grow upwards for more of a thriller effect. 

Fillers are all those delightful plants that we stuff into our planters to give them that full look: including foliage plants like coleus and Persian shield, heliotrope, marigolds, pansies, nasturtiums, African daisies, and more. 

Before you plant, select your containers and fill them with good quality potting mix. The joy of containers is that you can use pretty much anything as a planter—from shoes and skates to ornate glazed urns, to cast iron tea pots, kettles, wooden barrels, or trugs. The containers must have drainage holes, or you can set a slightly smaller pot with drainage holes into your ornate planter. 

It’s fine to buy premixed potting medium for your planters—not everyone has the time or energy to mix up batches of various components. Buy the best quality medium you can afford, preferably one that includes compost, perlite or vermiculate for better drainage, and slow-release fertilizer. If you’re using a large container, make sure you have it placed where you want it, as containers filled with soil and plants can get heavy.

Fall colour choices

• Ornamental kales and cabbage are completely irresistible, with their lacy foliage and bright colours. They will also look great well into winter.

• Annual grasses are eye-catching delights, boasting variegated or richly hued foliage (including burgundy, bronze, silvery blue, and more) and of course showy flowerheads. Among the most popular are fountain grasses like Fireworks, but also look for ornamental millets, “hair” grasses, and others. 

• Fall-flowering beauties include quintessential chrysanthemums in a rainbow of hues, plus asters, upright sedums, and pansies. 

• Did you know you can grow late-blooming perennials in containers? (See page 44). You can either treat them as annuals and let them go to sleep when the rest of the plants do, or else overwinter them in the container and grow on next year.

• You may find you have enough seed heads of some garden plants, such as echinacea and baptisia, or perennial grasses, to incorporate into planters for fall and winter. Branches of berries from native shrubs such as northern bayberry and Canada holly, or colourful rosehips also work well.

• The holiday season grows nearer, and who says you can’t start your décor outdoors a little earlier? Evergreen boughs are always popular, but don’t forget twigs from red stemmed dogwoods, twisted hazel, peacock willow, even pruned branches from lilacs. You can also buy long-lasting sprays of magnolia leaves, eucalyptus, euonymus and others if you don’t have enough of your own to harvest.

For the adventurous gardener:
year-round perennials in containers

Roxanna Boers is a graphic designer and gardener from the Halifax region (and part of the East Coast Living team). She excels at something that many gardeners have never tried: growing perennials in containers.

“Container gardening with perennials is very practical,” she explains. “It offers an alternative for space, environment and budget constraints. I do love the longevity of colour provided by potted annuals, but you need to buy them every year, which gets expensive, and it takes a while to grow them to any size, especially if you don’t have great light or heat. By the time your little garden starts to look good, summer is over and it’s time to clean up.”

Perennials bush out early and stay that way, she adds. “And they get bigger with every year. If you have evergreen types or interesting grasses, then you also have winter interest. With nothing but containers you can create a year-round outdoor garden almost anywhere: patio, deck, rooftop.”

Roxanna’s tips:

• Choose plants that are one or two zones hardier than your regular zone. Plants face harsher conditions and are less insulated when grown in pots. Most of us in the region are hardiness zone 5 or 6, so look for plants that are hardy to zone 3 or 4. 

• Look for plants that can tolerate a range of temperatures and not sulk if conditions get a little wet or dry. Some good choices include dwarf evergreens, coral bells, hostas, sempervivums (hens and chicks), dwarf rhododendrons, patio peonies, dwarf lilacs, astilbes, sedums, groundcovers like silver thyme or creeping Jenny, hardy grasses, and more. 

• The bigger and deeper the container you use, the better, regardless of what you plant. Large containers don’t dry out as quickly, and the plants don’t get as stressed, so it shouldn’t matter if you can’t water for a day or two. In cold weather, the extra soil in the pots helps protect roots from temperature fluctuations. 

• While it might be tempting to use beautiful glazed ceramic pots, not all of those are frost-resistant, and many don’t have drainage holes. One idea is to plant a large synthetic container (with drainage holes) and set it inside your ornamental pot for the growing months. Stay away from painted or coated plastics as winter will damage that finish. Terra cotta (clay) pots aren’t suitable for winter use in our region.

• Relax. If a plant dies, it isn’t the end of the world. There is always next year! 

East Coast Living