Secateurs on hold

Sunday, 02 August 2015

This Iresine herbstii is desparately in need of pruning

I find the first two weeks of August possibly the most excruciating in the gardening year. Yes, it's undeniable that there are wonderful signs of spring appearing day by day in the garden: swelling flower buds on shrubs and bulbs, the fuzz of baby leaves on deciduous trees, noticeably longer days and the increasing warmth in the air. What frustrates me is waiting a bit longer to prune off the ratty, winter-blighted stems of my warm-climate plants, which look absolutely awful right now. My fingers just itch to snip - and the sight of the shabby plants irks me greatly.

This Alternanthera dentata looks very tatty at the moment

However, mid-August has always been the time I choose to prune most (though not all) of these plants, as early August can be unpredictable: icy days can alternate with the early balmy days of 'sprinter', such as we experienced this weekend in Sydney. The ghastly-looking, straggly stems offer an element of protection to these tender plants, which if prematurely removed, can make the plant vulnerable to cold snaps, which in extreme cases might even kill a plant.

Salvia leucantha will be pruned soon

I have a huge binge of pruning come 15 August (or thereabouts) each year, gleefully cutting off all the old, tatty stems of plants such as Salvia, Justicia (and all my other Acanthaceae plants, apart from those still in bloom or just about to flower at the time!), Iresine herbstii, Tibouchina, perennial Cleome and all my shrubby and cane Begonia - followed by an application of an organic all-purpose fertiliser.

A sad-looking Pentas lanceolata

Other plants are especially cold sensitive, and these I leave until the first week of September: Pentas, heliotrope, coleus, Fuchsia hybrids, Alternanthera, New Guinea Impatiens and Clerodendrum species. We are fortunate that our Sydney climate allows these plants to flourish in the warmer months, providing literally months of blooms. They certainly don't like our winters, but the temperatures are not cold enough to kill them, as long as we don't prune them prematurely. (Next year, I am going to try giving them an occasional tonic of seaweed solution through winter, to see if that gives them a bit more resilience to the cold weather.) Holding off cutting them back until the spring weather is really here is a small price to pay for such handsome rewards. And they really should be pruned (and fertilised) then, because if left unpruned completely, they will be hideously straggly throughout summer and autumn, with fewer flowers.

If you are truly desperate to prune, roses, Hydrangea, Canna, Buddleja (apart from Buddleja salvifolia and Buddleja 'Spring Promise', which are about to flower!) and ornamental grasses that haven't yet been cut back should be tackled without delay.

This New Guinea Impatiens should spring back to life in September

The dates I have chosen for my pruning of my warm-climate plants may be completely superstitious. However, they seem to work for me in my north-west Sydney garden. Gardeners in colder suburbs should probably add a few weeks extra to my dates before they start to prune; those in warmer suburbs nearer to the coast can probably be less cautious than I am. However, if you have plants that look anything like the ones I have pictured in this blog (or worse?), just wait a little longer before wielding your secateurs is my humble advice ...

Reader Comments

  • By margaret 2122 Monday, 03 August 2015

    I am itching to prune, also, but know, from experience, to resist the temptation, as the early warmth of August can quickly be replaced by cold, and even, frosty weather. Mid-August is a suitable time to begin the task for many plants, although cane begonias are better left till late August, when the old canes can be cut to the ground, and the plants fertilized. New growth soon appears. Thanks for that clarification on the begonias. Will leave them a bit longer! Deirdre

  • By Sue 2074 Tuesday, 04 August 2015

    Know the feelings too and the secateurs are sharpened- my grasses are done, the hydrangeas and the only 3 roses I still have. I was planning to do my salvias this week as there is quite tall new growth happening.My cane begonias have 50cm new stems already and was contemplating if I should do the chop, but reading Margaret"s advice maybe will give it a bit more time. It"s interesting to hear when folk do their pruning though I guess each garden has it"s own microclimate. A helpful blog Deirdre. Thanks, Sue. The salvias that have a lot of new growth are fine to do now. I find the smaller-leaved ones (S. greggii and S. microphylla) more vulnerable as they have not started any new growth yet. My garden may be a little colder than others even in the same suburb as I am down in a dip. Deirdre

  • By Georgie 2099 Tuesday, 04 August 2015

    I have held back the secateurs for my hydrangeas & roses. I started, but am hesitant to complete the task. HYDRANGEAS:I find it difficult to determine where to cut their stems to promote flowering. I look for 2 large buds, which in some varieties are obvious. Others have spindly stems with pathetic single buds: how far should I cut in this case? Is it better to cut right back and allow new growth from the very base? As far as the roses, white scale covers the stems like snow. With the hydrangeas, some of the modern, dwarf forms do have quite thin stems. I would cut out about a quarter of the stems at the base, to encourage new growth and then trim to rest back to a bud, even if it is not plump. Give the plants some organic fertiliser afterwards, watered in well and put some compost or mulch around the base (not touching the stems). With the roses, maybe try Eco Pest Oil to get rid of the scale -- it sounds nasty. Hope this is of some help. Deirdre

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