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Get Your Blades Out

Early spring requires some pruning of tired old growth to rejuvenate woody plants and neaten others.

The secret of success with pruning relies on what, when and how to prune plants. You are not going to necessarily kill off a plant if you prune it at a different time of year, but doing it to some at the wrong time can result in a loss of seasonal flowering. Another point to remember is that spring pruning done too early in cold gardens that can receive late frost can cause damage to fresh new growth that has been stimulated – in this case, it is better to wait until the end of September or even early October. For the rest of us, it’s time to do some graft with the sharp blades.

Hard pruning of soft woody shrubs that have flowered in late summer and autumn:

How: Cut back all the stems to ankle high, leaving 3 – 4 nodes on each stem, which will produce the new growing season’s foliage and flowers.

What to prune: Mackaya bella, Plectranthus, Leonotis, Pycnostachys, Phygelius, shrubby fuchsias, Buddleja davidii, Caryopteris, Perovskia.

Rejuvenating pruning of neglected or overgrown large woody shrubs:

How: Cut them back to a stump of about 50cm high, and thin out some of the lateral branches. Using a sharp, long-handled lopper makes this task easier.

What to prune: Tecoma, Plumbago, Buddleja alternifolia, Philadelphus, Hibiscus rosa-sinensis, Hibiscus syriacus, Abelia, Berberis.

In subtropical regions you can do it from now, but in cold regions it is best to wait until you see the first signs of new growth on those that need the pruning.

Gentle shaping of conifers that are in active growth in the colder months of the year:

How: Never cut into old wood behind healthy foliage. Rather use a hedge clipper or secateurs to lightly shave the growing tips and foliage. This will ensure dense new growth leading to good-looking plants.

Gradual renewing of lavenders:

How: Begin by cutting back about a third to a half of the stems on each bush, leaving some foliage on them. Allow the pruned parts to sprout new spring growth before cutting the rest of the plant back. This a somewhat cumbersome process to follow up with in later months, but it allows many herbaceous shrubs to recover successfully from pruning back. Cutting back too hard (especially into old wood) can result in plants not recovering.

What else to prune this way: Santolina, rosemary, Eriocephalus africanus (wild rosemary).

Deadheading of aloes and perennials:

How: Use sharp secateurs to cut off dead flower stalks close to the crown or base of the plant after flowering.

What to prune: Aloes, Kniphofia, Bulbine, Kalanchoe and other winter-flowering succulents.

Caring after the big cuts

Fertilise all plants that received a drastic early spring prune with a general-purpose fertiliser, water deeply and renew the mulch around their root systems.

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The Gardener