Choose the right plants
Choose plants that either adore heat, sun and more heat or those that thrive in shade, depending on the conditions of your balcony.
Bougainvillea can be stunning on a hot, sunny balcony, as can agaves, cordylines (look for the reddish bronze ones or yellow and green striped ones), ornamental grasses of all kinds, any cacti or succulents; geraniums/pelargoniums, erigeron, white or purple alyssum, daisies, rosemary, lavender, sage, calendula, petunia, gazania, tomatoes, marigolds or even tiny Golden Nugget pumpkins or golden zucchini.
You’ll also find the ‘patio roses’ surprisingly indestructible, as are clipped bay trees and masses of nasturtiums.
As many exposed, sunny balconies are also very windy take this into consideration too. For those balconies where strong winds are a regular feature avoid the taller plants that will be whipped around in their pots, bashed against walls or railings or broken and avoid those with larger leaves that look bashed up after a good bout of windy weather.
One of the problems of potted plants is that any damage assumes undue significance – the odd tatty leaf or bent stem that would pass unnoticed in a garden bed makes your potted plant look like a battle-scarred survivor.
Shade lovers include many of the palms, like kentias – almost indestructible, zygocactus with their stunning winter blooms, hellebores, some of the succulents like houseleek and even cordylines again – we have some growing happily just under my study window in quite heavy shade.
Other shade lovers that do need regular watering include impatiens, pansies, ferns, fuchsias, polyanthus, Cape gooseberries and honeysuckle.
Keep them moist - somehow
The less soil is watered the more water repellent it becomes.
When you water most pots, the water runs down the sides, not into the root area!
Plants need repotting in fresh soil every year – or at least add water-retaining crystals every spring. You can also soak pots if they’re not too big. After an afternoon in a bucket of water the potting mix may absorb water again instead of repelling it.
Potted plants also dry out much faster than you’d ever expect. Even rain doesn’t wet the soil in most pots much – the leaves tend to direct the rainwater over the rim of the pot. A handful of water crystals added to each pot at planting time makes a huge difference to the capacity of the pot to hold enough water to grow lush and beautiful plants.
Clean the leaves
Most balcony plants don’t get rained on – and most gardeners water the base of their pot plants not the new leaves.
Leaves that aren’t regularly ‘washed’ get mite problems. Look at the leaves on plants under eaves and on balconies more closely. You’ll probably see tiny ‘tracks’ or spots where mites have sucked the sap – and that is why your plants seem to shrink and fade. They literally are shrinking and fading – and the mites are to blame.
ALL plants need to have their leaves washed at least once a week. Water the whole plant, not just the base – and with a hose, not a jug, so you can spray UNDER the leaves too, where mites like to hide.
(Dedicated balcony growers can rig up a spray system. We have one on our pergola here – micro-jets attached to polypipe and when they’re turned on the whole area is watered with a lovely misty spray – wonderful on hot afternoons. You can make them up yourself or buy one prefabricated.)
Tease out coconut fibre till it’s loose and cushiony and tuck it round the plant.
It won’t absorb moisture, so it won’t make the stems rot if you tuck it close in – but it will insulate the soil and stop it drying out and turning into concrete which is too hard for moisture to penetrate when you do remember to water. Many people prefer the neat look of small stones. You can buy lovely small white or grey or black quartz rocks at many garden centres – or collect your own pebbles to use as heat retaining mulch. (They’re not such a good idea where there are toddlers, either in permanent residence or visiting, as they are irresistible to small children – either for inserting in small orifices or, if the pebbles are too large for those fascinating games, for throwing over the edge of the balcony onto passing cars or pedestrians.)
Feed them well
Well fed plants are healthier- and they cope with heat, cold and drought better too if they are big healthy roots.
Slow release plant food is best – there’s a wide range on the market. Just browse along the shelves. I like to give my pots a treat of seaweed-based fertiliser once they start leaping up in spring. Use according to directions.
If you've got brown thumbs - admit it!
No one really does have brown thumbs – plants will thrive for all of us IF we have the time to look after them!
If your life hardly has time to cosset yourself, much less your plants, stick to VERY hardy plants – pink, white or yellow daisies (the white ones are the hardiest), bamboo (ALMOST unkillable), poa tussock, geraniums/pelargoniums, weeping rosemary, oleander, weeping bottlebrush (Callistemon viminalis), heliotrope in frost-free areas, westringia, brachycome … or even dull old ivy, that can look luxurious trailing from a hanging basket – and is almost maintenance free. (Just don’t grow it where it can go wild!).
If the situation is really impossible (hot, dry and windy but you do get sun) stick with succulents and cacti, most of which have interesting leaf shapes in a good range of colours and some of which have spectacular flowers. (And not all are prickly horrors either.) Some even tolerate shade!