Mary, Mary, quite contrary,
How does your garden grow?
"I live with my brat in a high-rise flat,
So how in the world would I know?"
Oh Mary, Mary of the black-thumb brigade, by Roald Dahl, how you have been mislaid. In fact, unlike for your soil-breaking brethren at ground level, there are many advantages to high-rise horticulture.
No soil problems--you bring in the best light-weight mixes
No digging, hoeing or mowing
No weeds unless you bring them in with plants from the retailer
The higher you are, the brighter it will be--not necessarily full sun if you are north-facing but still with more light than at ground level.
If you are more than four storeys off the ground, you will face less problems with pests--other than, of course, pigeons (more about that later)
Choose ten-inch or wider diameter planters to avoid rapid loss of moisture and to keep roots cool, a possible problem high off the ground. Place a sheet of paper towel over the drainage holes to prevent dirty water oozing out, then fill with light-weight professional grow medium.
Unless you want to hear abusive language from neighbours below you, place saucers under all planters to assure excess water doesn't drip down onto the less than green-thumb enthused.
Let nothing hang outside the balcony railing. A falling window box or other container, however apparently securely fastened, could come loose and fall on someone below. This could damage, even destroy the plants.
Now, Mary, you are ready to plant your dream garden. The best bet for the beginner are annuals.
Surprisingly, as the summer sun reaches high in the sky, even the rear of balconies facing it may be cast into shade. Shade-tolerant annuals are the answer here, as they are for north-facing cliff dwellers.
Which are the easiest? Don't neglect watering and two begonia selections, 'Dragon Wing' and 'Waterfall', will provide a magnificent, reliable display the entire season. Old favourite Geranium is an all-round standby for full, blazing sun.
=Some plants, such as the above Begonias, are "self-cleaning" dropping their blooms when they are finished. Clear Geraniums of theirs to encourage blooming through late in the season. The appropriately named cousin, the Ivy-leaf Geranium is best planted where it can trail over the edge of its planter.
Petunias, another old favourite, also self-clean but tend to 'run out of puff' later in the season. Modern cultivars do better and are often scented as a bonus. Other scented choices include white or purple Alyssum and white Nicotiana. Calendula or "Pot Marigold' and the border Marigolds (Tagetes) also offer a fragrance of an unusual sort as do tall, shade-loving Cleome.
Cannas, Dahlias and Lilies all grow from below-ground storage organs. They can add height to the balcony garden. Many Lilies are deliciously scented but, alas, bloom for a short time only.
Impatiens, a long standby for shaded areas, has fallen by the wayside thanks to attacks from a persistent pathogen. Even before this, some high-rise horticulturists experienced problems whereas for others it flourished.
Many annuals are utilized for their foliage, contrasting and setting off blooms of others. Some, such as Caladium and Coleus come in colours of their own. The silver foliage of Dusty Miller offers high contrast. Trailers should be planted along the edges of boxes and planters. Choices include Asparagus Fern, Lamium, Sweet Potato Vine and Vinca.
There seems no limit to ornamental grass size and form. Tall selections centred in planters set off all else, as well lower species towards the container edges. High up, most grasses seem to tolerate some shade and are even attractive left during winter.
The enormous leaves of the Castor Bean Plant bring tropical allure to high-rise horticulture. If visitors are not already exclaiming at your "jungle" they will when they catch sight of one of these plants. Further intrigue them by positioning pots of Scented Leaf Geranium where they will be brushed past, so releasing their delicious scent. If you cannot locate these locally, check out richters.com.
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A few half-hardy tropical shrubs such as hibiscus and bougainvillea may be successfully overwintered inside the apartment by keen hi-rise hands. Most require a sunny exposure so are unsuitable choices for residents of north-facing abodes. Fuchsia and Lantana are window box selections. Abutilon, Brugmansia and Datura form small shrubs although the latter two, spectacular as they are, are poisonous.
Then there are herbs, even vegetables. All except mint and chervil need full sun.
True, there are possible problems. The principle one is wind. Some plants dislike strong wind and hot, dry conditions these create around tall buildings. But there are many that tolerate, even flourish when thus exposed.
The wind also means that a fountain or waterfall may not be such a good idea. True, the sound of falling water is a delight. Unfortunately, pools can quickly be blown dry, causing pumps to burn out. Consider switching off the pump when not home.
You will want to sit out and perhaps entertain friends. If so, make sure the furniture is heavy enough not to be blow around.
Then there is the problem of Columba livia domestica, or pigeon to you. Its ancestor was the rock pigeon and it finds the human caves of apartment buildings just dandy nesting sites. Squirting with a water-gun may be fun but the only permanent solution is professionally installed netting.
A final word of advice: don't step back to admire your work
Wes Porter is a horticultural consultant and writer based in Toronto. Wes has over 40 years of experience in both temperate and tropical horticulture from three continents.
