I think pruning is one of the trickier aspects of gardening. So much depends on the climate or even the microclimate where you live. And there aren't blanket rules that can be applied to every plant, such as 'Prune hard after flowering'. Whilst that adage works very well indeed with spring-flowering shrubs, such as Weigela, Deutzia, Brunfelsia, Rhaphiolepis and some of the cold-hardy Salvia plants such as Salvia microphylla, along with most Australian native shrubs that bloom in spring, it can cause problems if applied to other sorts of plants, For example, in Sydney, pruning summer- and autumn-blooming shrubs from semitropical climates after they finish flowering, in late autumn, can harm any new growth that may appear during winter, when we get cold snaps such as the one we have been experiencing for the past week. Yet in warmer, protected microclimates close to the coast, this won't usually be an issue.
When I first started gardening, I would simply prune any plant that looked terrible. That would mean razing my entire garden in July, when it looks at its absolute worst. I have learned over time that there certainly is quite a bit of pruning that can be done in July, but also there are plants best left till around mid-August. Hence, I have to turn a blind eye to the sad-looking specimens that really don't like the cold. I have to remind myself that they need the protection of their shabby, straggly foliage just a little bit longer during these icy days, and that in just three short weeks, I can give them the big haircut they need to begin to grow all over again into their wonderful warm season forms. These plants include Justicia, semitropical Salvia (as long as they have finished flowering!), Plectranthus, Iresine and Tibouchina. I wait another extra week before I tackle my cane and shrub Begonia.
There is another group of plants that I wait even longer to prune - those that are especially cold sensitive. These I leave until the first week of September: Pentas, heliotrope, coleus, Alternanthera, 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. An alternative to putting up with their winter look is to propagate them from year to year from cuttings, kept protected over winter, and then simply turf out the original plant,
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.
The things we can prune now are numerous, for those of us with itchy secateurs. Roses, for example, are pruned now, except those that will flower in early spring, such as banksia roses. Fuchsia are best pruned now, cutting them back by about half: young specimens can be trimmed more lightly. Hydrangea bushes can be pruned now. I cut the dead flower heads back to the first pair of strong plump buds closest to the old flower head. Weak, straggly stems are taken out at the base, and I also remove completely a couple of very old, gnarled woody stems each year. Lacecap varieties are pruned more lightly, cutting back to the second pair of leaves below the old flower heads.
Buddleja also benefit from a hard prune now -- apart from Buddleja salvifolia, Buddleja 'Spring Promise' and Buddleja 'Wattle Bird', which are about to flower! Sasanqua Camellia can be trimmed to shape now that they have finished blooming, plus any Camellia japonica that are at the end of their season. Don't prune any spring-flowering deciduous shrubs even though they might look like dead sticks at the moment - you will be cutting off all their buds!
Deciduous ornamental grasses that haven't yet been cut back should be tackled without delay, as should any old Canna and Dahlia foliage. Prune to the ground in all cases. I also cut back some of my strappy-leafed, evergreen plants around this time. I remove Kniphofia foliage right at ground level once flowering is over. I also cut back Liriope foliage to the ground if it is shabby. Daylilies that haven't already had their foliage removed can also be done now, Fresh growth will soon appear.
Thank you, Deirdre, for your timely reminder of pruning time for some plants. I have hydrangeas to do and fuchsias. I have never pruned my fuchsias by half, but will try this time. I did prune my buddleja lightly some weeks ago, but will prune some more now, into a better shape. Hope you've been able to do your pruning - the warmer weather last week was quite conducive to gardening: not so the icy winds of the weekend! Deirdre
It's such a straggly time of year. The liriope is especially ratty and I am wondering if it can stay out the front as when cut to the ground it's naked for at least two months. I did cut back the Plectranthus earlier and hoped it would be ok. Fortunately there are the first new shoots appearing so fingers crossed it will continue. Have hung on to the hydrangeas as they have been so nice and I still have a white one just out, but it's time. A good reminder blog. Yes I still had a few aged hydrangea heads that I didn't want to cut off but forced myself to do it last week! I think I need to experiment a bit with some of the plants to see if I can cut them back earlier to spread the workload out a bit more. Deirdre
Thanks for your very useful pruning info. I am a bit late with everything this year which is probably for the better after reading your notes. Though I havent cut back grasses so will see what jungle occurs there. That should have been done earlier? I do tend to do my ornamental grasses in June, only because the new growth seems to come through quite early and if they are left unpruned much longer, the new growth can be cut off as you cut the old leaves. However, it will regrow. Deirdre
Tackling a corner
01 Sep 24
Divide and conquer to get garden work done!
Salutation to clivias
25 Aug 24
Clivias herald spring to me!
Pretty in pink
18 Aug 24
Pink seems to be the colour of the moment.
Multiplication by division
11 Aug 24
This is a quick way to propagate plants.
On bare branches
04 Aug 24
A profusion of blooms on bare branches announces that spring is almost here.