If you really only use your deck to keep the recycling bins out of the kitchen, you're missing a great opportunity. With a little planning and a few choice plants, a deck can become the heart of your garden, instead of just a useful extension of the house.
When you arrange plants in pots on a deck and plant a flower bed around it, you're tying the spaces in your yard together. Large flowerpots have the most impact, and they also need less frequent watering than plants in small containers. Plastic pots that resemble weathered terra-cotta are lightweight and easy to move around.
On a sunny deck, fill pots with long-blooming annual flowers and tropicals that can take the summer heat. A pot of herbs mixed with marigolds looks great, or try a dramatic flourish of purple fountain grass or ornamental millet, striped-leaf cannas, or a combination of verbenas, nasturtiums, zinnias, and lantanas.
On decks shaded by house walls or trees, plant hostas, caladiums, or lush ferns in pots. White impatiens sparkle in dappled light and bloom all summer long. Small hydrangeas also look elegant in pots in light shade.
If the deck is on the west side of your house, a trellis or an arbor will cast some pleasant shade on hot summer afternoons. Flowering vines soften the architecture of these structures. Morning glories (or moon flower) are easy to grow; ornamental gourds or feathery cypress vine (Ipomoea quamoclit) will also cover an arbor in no time. They can all be grown in pots.
A garden on a deck should be just as interesting and well designed as one in the ground. Incorporate fragrance in the design by planting heliotropes, flowering tobacco (Nicotiana), herbs, or roses. Add water: a fountain or pond beside a deck may be close enough to appreciate, or you could plug in a small, self-contained bubbling fountain. Plant milkweed (Asclepias tuberosa), salvias, lantanas, and butterfly bush (Buddleia davidii) to attract butterflies and hummingbirds to a deck, so you can enjoy them up close.
A deck is part of both the house and the garden. It gets you out into the air and gives you a convenient and comfortable place from which to appreciate your handiwork in the rest of the garden. Once it is properly planted and furnished, you're likely to spend much more time outside, and you’ll have a fresh view of the nice combinations of blooms in your flowerbeds. A well-planted and furnished deck opens up your perspectives.