Fall containers need special treatment. It's easy to design a colourful summer container: petunias, verbenas and begonias are bred to bloom all season. Come fall, though, these frost-tender annuals will be ready for the compost. And although mums and asters add a quick blast of colour to fall planters, they fizzle out all too soon, leaving their browned-out blossoms on the doorstep.
The Toronto Botanical Garden's container-crazy Paul Zammit knows how to make an impression – without using flowers. "I love flowers, but I value and appreciate leaves more," he says. For Zammit, it's all about colour, texture and motion from foliage. One of his favourite container plants for fall is Carex buchananii, a leatherleaf sedge with golden brown, wispy foliage. Mexican feather grass (Stipa tenuissima) is another good foliage plant that stands up to hard frost better than the more popular purple fountain grass, which can turn to mush, he says. Zammit also recommends using plants with long petioles, or leaf stems, such as any of the coralbells (Heuchera cvs.), which he weaves through the foliage of other plants. He's also partial to the bold foliage of broad – and waxy-leafed bergenia and any of the many hellebores with their finger-like leaflets. Whichever plants you choose, though, plant densely. "Plants will not put on much growth in the fall," says Zammit. Select enough plant material to instantly fill the container.
Small evergreens can form the foundation of fall arrangements, says Zammit, who uses pyramidal boxwoods, young cedars and cypress (Chamaecyparis spp.).With the addition of boughs and holiday finery, these can be carried through into winter arrangements. Evergreens also add height to the design, as do small deciduous shrubs such as an upright, multistemmed buckthorn called Frangula alnus 'Aspleniifolia' (also sold as Rhamnus frangula 'Aspleniifolia'). This is one of Zammit's favourites because of its dark stems that contrast with the golden, finely textured fall foliage. Ornamental grasses, branches of all sorts, including grape vines, mossy stems and canes with rosehips can add height, too. Zammit also likes to place a small trellis or obelisk in the planter and attach seasonal ornaments such as outdoor lanterns, gourds and mini-pumpkins to them.
Although the hot summer sun has cooled to burnished autumn gold, containers still require moisture. "People think they no longer need to water containers (and gardens too) because of the cooler overall temperatures," says Zammit. But this is not the case. "It is surprising how quickly planters can dry out, particularly those in windy locations," he says. Use your fingers to check the growing medium for moisture every day or two, and water accordingly.