Salvia Love and Wishes needs to be replaced every few years

When I first started gardening, I assumed that all plants should last forever, and it was an affront if they didn't. However, as the years have passed, I have come to realise that various small shrubs and bushy perennials often seem to get to a point where they are no longer very productive after a few years, and we need to remember to take cuttings of them so we can start again with a fresh specimen. I wouldn't bother to do this with plants that don't earn their keep, but certain ones really do deserve to have an ongoing presence in our gardens because they flower for so long and so profusely. We can hardly begrudge the fact that they simply seem to flower themselves to death. Once we have accepted their essential impermanence, it's up to us ensure they can remain in our gardens. The fact that we replace them means we can try them in different spots, thus refreshing our gardens in this way.

A favourite Abutilon from the garden of Jill Fraumeni in Sydney

A favourite Abutilon from the garden of Jill Fraumeni in Sydney

Those most in need of this treatment seem to be warm-climate plants from places like Central and South America, Mexico and South Africa. Interestingly, many of these have taller forms that are unavailable from nurseries, and compact forms that are seen for sale. Often it is the taller ones that are more useful in the garden and so we can't just buy another one when the original gets too old: we need to propagate then ourselves. In fact, to get them in the first place, we need to get a cutting from another gardener, from the sales tables at a garden club or possibly from a stall at a fete! Luckily, they strike easily from cuttings and grow quickly into a robust form. One such plant is Abutilon, which blooms literally non-stop from March until November, with lovely lantern flowers in range of soft and brilliant hues. I find they are good for two to three years then start to become rather gangly. The tall ones form a good-sized shrub; the smaller ones are best for compact spaces or pots.

Pentas lanceolata

Pentas lanceolata

Pentas is another free-blooming shrub that bears colour over a lengthy period from November to May, in its posy-shaped clusters of dainty star-shaped flowers. Again, after two or three years, the shrubs get woody and less productive. I have discovered that keeping cuttings in a vase of water (covered with a plastic bag) on my windowsill is a good way to propagate the plant, which can be a bit hard to strike in a pot. As with Abutilon, I think that the best Pentas are the taller, old-fashioned ones (ht 1-1.5 m), rarely if ever seen in nurseries, rather than those bred to be low, rounded forms that are available for sale.

Plectranthus Mona Lavender in the garden of Anne Prescott in Sydney

Plectranthus Mona Lavender in the garden of Anne Prescott in Sydney

Plectranthus is another genus where fresh plants every two or three years will give the best flowering, for the shrubby forms: the groundcovers keep going for ages, as long as they are trimmed back after flowering. Plectranthus ecklonii, with its soft feathers of pink, purple or white through late summer and autumn, the Cape Angels series, 'Mona lavender' and Plectranthus zuluensis get woody after a while. They are very easy to grow from cuttings, which regrow quickly into your new plant. Recent years have seen a commercial interest in Plectranthus and the development and marketing of some of the low-growing forms, but again, the larger varieties tend to be those handed from gardener to gardener and grown from slips.

Argyranthemum frutescens cultivar

Argyranthemum frutescens cultivar

Marguerite daisies are another plant type where regular renewal of old favourites is necessary. Whilst it is possible to buy new low-growing ones every year from nurseries, once again the traditional taller types are rarely seen there and we need to propagate them ourselves if we want to have them in perpetuity. They flower so generously and for such a long period through winter and spring, that it is hardly an impost to take a few cuttings every year or two.

Salvia x jamensis Mesa Azure

Salvia x jamensis Mesa Azure

Many shrubby Salvia, need to be renewed every few years, especially the 'Wish' series, Salvia microphylla and Salvia x jamensis cultivars, Salvia splendens, Salvia fruticosa and Salvia 'Van Houttei'. Fortunately, a number of these are now available in nurseries, so it is possible to buy fresh plants. They make such a valuable contribution to Sydney gardens through summer and autumn that I would never want to be without them.

For my tips on how to grow softwood cuttings (best suited to these plants), visit this page.