Camellia Eryldene Excelsis growing at Eryldene, Gordon NSW

A visit last week to a fascinating old historic home turned my thoughts to the effects wrought by time on buildings, gardens and plants. Some plants, mainly trees - as in the magnificent Moreton Bay figs and native pines at the property I visited - get better and better with time, growing into a mature grandeur that can last for many decades or even centuries. Camellia shrubs also seem to improve as each year passes, as they achieve their full potential and become smothered with flowers in autumn or winter. Many evergreen shrubs, such as Viburnum tinus, Loropetalum chinense, Euonymus japonicus cultivars and Mackaya bella similarly are enhanced by each passing year, requiring little maintenance.

Salvia gesneriifolia

Salvia gesneriifolia

However, I have recently noticed that a lot of the plants in my garden are starting to look rather tired. These are generally shrubby perennials or sub-shrubs - such as my many Salvia specimens, for example. As my passion for these plants reached its zenith about ten years ago, many of those in my garden have probably passed their peak of robustness and are becoming very woody and producing fewer blooms. Perhaps because I cut them down so ruthlessly each year in late winter, the constant requirement for renewal eventually takes its toll on the vitality of the plants. Plectranthus, too, which are also pruned hard every year, do seem to reach a stage of decrepitude that requires them to be heaved out and replaced by a new plant. Many of my Salvia and Plectranthus now need to be replaced by cuttings, which I plan to take in spring. Luckily this is an easy process, as they take root quickly and soon grow into sturdy plants.

Pentas lanceolata

Pentas lanceolata

Other plants that also seem to reach a 'use by' date include Pentas lanceolata, one of my favourite little sub-shrubs, which flowers almost all year round. Perhaps it is this very feature that eventually wears them out. Lavenders also seem to exhaust themselves after a few years in Sydney gardens, and become quite ratty looking. Heliotrope, Marguerite daisies, Fuchsia hybrids and mountain marigold (Tagetes lemmonii) are other plants that I have noticed become straggly and unproductive after a few years in my garden.

Change is inevitable in any garden, as these plants come and go - but I have begun to realise the need for an enduring framework of more solid plantings. Gardeners, too, start to lose some of their energy as they get older, and I can imagine a time eventually when all the cutting back of the sub-shrubby sorts of plants and the need to replace them every few years may become too daunting. Hopefully, not too soon!