Your spring pruning guide
It’s time to tidy up winter-flowering plants, and prepare those beauties gearing up to flower in late spring and summer. Sharpen your tools for some satisfying spring pruning
Spring pruning is generally carried out for two reasons: the first, to set up plants that flower on new growth through the warmer months; the second, to tidy up winter and early-spring flowering plants and prepare them for their next flowering season.
If you live in the tropical or warmer subtropical regions, you can safely whip out your secateurs around August. In cooler, frost-prone areas, it’s best to wait until the weather warms a little, to avoid any frost damage to new growth.
The most important thing to remember is that pruning is all about observation. Spend a bit of time looking at your plants before you start; not just close up – for disease or other issues – but by standing back to review their overall shape and proportion in the context of your garden.
1 LATE SPRING AND SUMMER FLOWERING PLANTS
Flowering shrubs, such as plumbago, Chinese lantern, angel’s trumpet, hibiscus, oleander and acalypha, all require pruning at the beginning of spring to encourage the fresh new growth that will go on to produce flowers. While they’ll still bloom if you don’t prune them, a light trim, or even a serious chop, will maintain the shape of these plants and stimulate a super flush of foliage and flowers.
How far can you go?
Generally speaking, most of these plants thrive best when they’re pruned in a way that’s sympathetic to how they prefer to grow. Consider how vigorous they are. Fast, vigorous growers can handle being pruned back by at least half, while more moderate growers only need to be cut back by about a third to a half. Plants with a slow growth habit, typically those with a smaller, more compact form, only need a light trim of up to a quarter.
Don’t forget, once you’ve done an initial trim and are happy with the plant’s size and shape, it’s important to check through the branches and prune out any congested
and rubbing branches. Diseased or dead wood should also be removed at this point.
Chinese lantern and hibiscus These closely related shrubs both handle a hard prune, particularly if overgrown. Otherwise, follow the rules of thumb above. If you’re happy with their shape and size, give them a light prune; otherwise, go for it and cut them back by up to half. (See ‘How to prune hibiscus & Chinese lantern’, opposite.) Angel’s trumpet (Brugmansia spp.) Pruning will depend on how this has been trained to grow. If you want to maintain it as a low-growing bush with multiple stems, cut into the heavier wood and reduce the height by a half or so. If it has a standard form with a single bare trunk, then a light prune of up to a third of the canopy will encourage optimal flowering in summer.
Oleander This can be pruned in much the same way as angel’s trumpet. Maintain its desired shape with a prune of up to a third over the entire canopy. Is it turning into a triffid? Then cut it back by half or more. Note that oleander and angel’s trumpet are toxic, so care should be taken to avoid ingestion, or any skin or eye contact, while you’re working on them. Wear gloves, goggles, if necessary, and a long-sleeved shirt.
Plumbago This is always at its best through late spring and summer, and doesn’t need much of a prune to maintain it. It flowers on new growth, so a light trim of the old stems after flowering will encourage its next flush. If it’s lost its way, give it a chop, almost to ground level if you like, then guide the new growth into shape. Acalypha Use secateurs or loppers, rather than shears, to maintain this plant’s bold and bushy habit. Simply cut it back hard, by half or more and enjoy the resulting show of attractive new foliage.
2 WINTER AND EARLY SPRING FLOWERING PLANTS
Plants in this category range from a wide variety of natives, including wattles and grevilleas, to camellias, azaleas and gordonias. These plants form their blooms on summer and autumn growth, so pruning them straight after they’ve flowered gives them ample time to produce next season’s wood from which the flowers will appear.