Before planting up the window box, I applied Black Gloss Tremclad Rust Spray Paint to match the artificial branches. Next, I lined it with moistened sheet moss, then added a layer of plastic; small perforations were made to allow for drainage.
Four branches were used to create two sets (each pair of branches was tied at its base with floral wire). These sets were positioned at varying heights in the arrangement using different-sized Oasis floral foam. Each set was inserted into its respective foam and secured in the window box by firmly packing potting soil around the foam bases. More potting soil was added to fill the balance of the container.
Next, the live material was added (before planting, water specimens in their original containers). First in were the spurge, positioned very close to the base of the branches, followed by the flowering cabbage and bugleweed. Moistened sheet moss was again used to cover any remaining exposed soil.
Finally, the miniature pumpkins were arranged, carefully (and discreetly) secured with 22-gauge florist wire.
To keep the container looking fresh, be sure to remove any fading foliage. In late fall, before the ground freezes, remove the perennials (the Black Scallop bugleweed) from the container and plant into the garden to overwinter; they can be lifted and reused next year.
Paul Zammit is the director of horticulture at the Toronto Botanical Garden.