Growing plants in pots on patios

Press, 23 February 1989, Page 27

Growing plants in pots on patios

GARDENS

with

Jim Heard

Container gardening allows plants to be cultivated in almost any desired position and at any height, hanging from ceilings or beams, on window ledges, roof tops or balcony rails, in narrow corners, or in places where plants would not normally thrive. When choosing a container, remember pot plants should “fit in” and be in proportion for the selected position of the container. So many mistakes occur with eighter too large a potted tree in a tiny pocket handerchief coutryard or a miniature shrub in a huge planter tub. A tub, 50 cm wide and 40 — 50 cm deep will be adequate for the continued growth of even a large shrub for many years. Ensure that the pot has sufficient drainage holes, and place a

generous layer of drainage material such as broken up clay pots, gravel, or charcoal which helps to keep the soil sweet, in the bottom. The potting mixture should consist of sandy loam, garden compost, peat moss, river sand, and if available, some well-rotted manure. There are several excellent commercially preparedpotting mixtures available for those gardeners who are unable to make their own. Ensure that the root ball of the shrub to be potted is moist before it is taken from its existing container. When planting, set the top of the root ball just below the rim of the pot. As the potting mixture is placed around the root ball, it should be firmed in with a piece of wood.

Continue adding and tamping the potting mixture until it is about one centimetre below the rim of the pot. Water the shrub thoroughly after planting, and whenever the soil surface begins to dry out. Most container-grown plants need regular pruning to keep them healthy, tidy and in good condition. Often they need to be given some form of support as well. These operations are closely interlinked especially in "training,” when a plant is encouraged to grown in a particular shape. After several years, when roots become compacted in the pot, the plant can be removed in mid-autumn, and about two centimetres pruned from the perimeter of the root ball. Foliage can be pruned back, and the potting mix changed at the same time.

Scrub out the container before adding fresh gravel or broken pottery and the fresh potting mix.

It is particularly important to ensure that container-grown plants are fed regularly, because

the small amount of potting mixture in a pot may contain only enough food to supply the plant for a few months. Watering also washes away the nutrients in the potting mix. Plants should be fed only when they are actively growing, not in their dormant period. Never feed plants that are dry without watering them first. Avoid applying fertiliser in strong sunlight because of the danger of scorching the foliage. Always use the fertilisers of liquid feed according to the manufacturers’ directions. When making up liquid feed, mix thoroughly, and keep well agitated during application. Use tepid water, never cold water. Pellets and fertiliser sticks are a convenient form of slowacting fertiliser, such one lasting two to three months at least. The following list of plants, as well as annuals, do well in hanging containers: Ivy geraniums, sollya fusiformis (Australia Blue Bell), Impatiens (Water Fuchsias), Hedera (Ivy), Fuchsias, Begonias, Convolvulus mauritanicus, Abutilon megapotamicum, miniature roses, Lithospermum and Dampiera. The plant you choose must depend on the size of your container. All annuals, most bulbs and many perennials do well in containers, but just a few ideas are: Miniature roses (standard or shrub), geraniums, camellias, agapanthus (blue and white), flax, bamboo, oleander, Lauris (bay tree), Hibiscus, hebes, lemon tree, conifers and azaleas. With all plants in containers, the pot and plant can be greatly highlighted by planting annuals around the shrub. These are of course removed when they die off in winter. Change the annuals the minute they become straggly and tired-looking and replant with annuals suitable to the season. Probably the most popular use of containers today is for growing herbs which are both useful and attractive.