Garden Care – Do Perennials Need Less Maintenance Than Annuals?

Apr 23
07:25

2008

Jonathan Ya'akobi

Jonathan Ya'akobi

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Many home gardeners equate the growing of perennial plants with low-maintenance gardening. There are some excellent reasons for preferring perennials to annuals, but saving time and maintenance costs is not one of them.

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It is common to find amongst home gardeners,Garden Care – Do Perennials Need Less Maintenance Than Annuals? Articles the idea that perennial flowering plants demand far less care and attention than annuals. As annuals live for no more than a season, an annual flowerbed has to be re-planted at least twice during the year, and more usually once more within a season. Conversely, because perennials live beyond a single season, they are often considered a factor in “low-maintenance gardening”. This view from my 24 years gardening experience, is false.

The truth is that successfully growing herbaceous perennials is one of the most labor-intensive activities in the gardening task book. Many plants require frequent clipping and pruning in order to encourage dense growth and a compact form, while if left to their own devises, merely become long and leggy. Timing is often all-important, particularly with perennials that originate from Mediterranean climates. Good examples are many of the South African perennials like Arctotis, Osteospermum and Lampranthus, where unless one’s finger is held firmly on the pulse, the aesthetic value of such plants is lost very quickly.

Neither is the term “perennial” always sufficiently understood. Some species look poor within a year or two, and need to be replaced, albeit less frequently than annuals. In short, it is not possible for a flowerbed comprising largely of perennials to perform satisfactorily through the year, without constant, clipping, lifting, dividing, replacing and re planting. From the point of view of time spent, and energy expended, replacing annual bedding plants every so often, is probably easier than maintaining a perennial border.

Yet there are two very good reasons for growing herbaceous perennials. Firstly, our gardens would be so much the poorer without them. Some of the finest non-woody flowering plants are perennial – Salvia, Chrysanthemum, Verbena, Dianthus, Digitalis, Geranium, Viola, Delphinium – the list is endless.

The second reason is more specific to dry climates and concerns water management. Overall, annuals in Mediterranean climates require at least 1000 mm (1000 liters per square meter) of irrigation water a year. In continental climates, such as the American Mid-West, or Central Asia, the requirement is considerably more. This colossal consumption rate is untenable in dry and not so dry regions, and so the use of annual plants must be severely restricted. By way of comparison, many perennials such as Salvia and Chrysanthemum can be grown on less than half that quantity, while some species like Lampranthus or Drosanthemum, (Ice Plants) can survive on seasonal rains alone. In dry climates therefore, annuals are best restricted to limited use in pots and containers, and grown primarily during the wet season.