Filling summer gaps

Sunday, 03 February 2019

Potted colour ready to plant

It goes against all my usual advice ('Plant only in autumn or winter!'), but I have been popping a few things in lately. It is certainly not the ideal time to be doing so, but I found I had some gaps in my garden and I felt compelled to fill them. I've mainly used 'potted colour' from the local nursery, so it won't really matter if they don't last too long. I would not plant an expensive shrub or tree at this time of year, but advanced pots of robust summer annuals can be put in to plug gaps and give the jaded gardener a boost - and it feels like doing gardening, something I think many of us poor Sydneysiders are desperately missing at the moment, when watering to keep our plants alive is about all we can manage in the relentless heat.

Aquilegia can be short-lived in Sydney

Gaps in the summer garden can arise when certain plants are dormant in the hotter months - such as Acanthus mollis or some Alstroemeria cultivars - or where a plant suddenly dies. Fatalities can happen quite a lot at this time of year, because the heat and humidity can cause horrid fungal diseases that can take out a plant very quickly. Likely candidates are perennials with low-growing, basal foliage - vestiges from my English cottage garden phase - which are really not very suitable for growing in Sydney but we gardeners often can't resist planting these beauties, such as Aquilegia. They may last a year or two - but come mid-summer, they can drop dead overnight. Linaria purpurea is another example that can be short-lived but, like the Aquilegia, it usually provides a legacy of self-sown seedlings in the following spring. Silvery-leaved lambs' ears (Stachys byzantina) often starts rotting off at this time of year, though usually enough remains of a clump to keep it going. Strappy-leaved plants that form clumps can also get fungal diseases at this time of year; keep an eye on plants such as Arthropdium and Kniphofia, for example. Remove any affected leaves and spray with an organic fungicide.

Catharanthus are excellent summer annuals

Many warm-climate shrubby perennials that grow well in our Sydney climate do have a shelf life, and need to be replaced by a younger specimen every few years. Sometimes old plants just suddenly give up the ghost, and one can hardly blame them in this vile summer we have been experiencing. Pentas, Plectranthus species, heliotrope, Cuphea, Osteospermum, so-called perennial Cleome and Fuchsia hybrids are some examples; I need to remember to take cuttings of these each autumn as a precaution. They flower so profusely and over such a long period of time that it is no wonder they eventually run out of steam! In the resultant holes, I have planted some sturdy hot-pink and some purple Catharanthus, sometimes known as vinca. These heat-loving plants are usually sold as annuals but I have found some live on to flower another year and even may self-seed to give extra plants. They come in a range of hues, including white, pastel pinks, reds and some luscious dark wine colours too.

Coleus plants are good fillers for summer gaps

Trimming back overgrown plants can also often create gaps that one craves to fill, even if just whilst waiting for regrowth to occur. This week, I cut back the messy foliage of my ornamental grass Miscanthus sinensis 'Variegatus', because it was leaning over and smothering nearby plants. There was so nice new upright growth in the centre of the clump but then a huge bare circle around it once the leaves had been chopped off. Here I have popped in some dark-leaved, white-flowered bedding Begonia and some self-seedlings of Euphorbia 'Diamond Frost', which speedily forms a spangled cushion of bloom. Other fillers that can be tucked in at this time of year include pots of coleus and dwarf bedding Dahlia.

Tradescantia zebrina

For spaces where a herbaceous perennial is dormant, such as the Acanthus, I often just drop pieces of decorative Tradescantia zebrina in the spot - this very obliging shallow-rooted groundcover will quickly cover the ground, to be pulled up once the plant starts to regrow. I sometimes use the same ploy to cover spots where spring bulbs have died back. Other quick fixes for gaps - especially in shaded areas - are bromeliads. As described in a a blog a few years ago, they can be divided up and replanted in empty places in no time at all. There are so many different varieties, with beautifully coloured leaves and unusual flower spikes, and they need very little maintenance.

Even if you have no gaps in the garden, planting up some potted colour in some low bowls or tubs can bring instant joy. It's also a way of supporting your local nursery: I'd say they are doing it tough in this merciless summer.

Reader Comments

  • By Bren 2540 (Zone:10 - Warm Temperate) Monday, 04 February 2019

    Catharanthus (Vinca), I agree is a great filler. As you say it self seeds, and in a couple of generations reverts to a "wildtype" with either white or purple flowers. The foliage of these wildtypes is also much tougher than that of the cultivars from the nursery. I have seen the purple ones growing in quite extreme conditions in the Middle East and Central Africa. Thanks, Bren, that is interesting that the self-seedlings revert to a tougher form. Deirdre

  • By margaret 2122 (Zone:10 - Warm Temperate) Monday, 04 February 2019

    I can"t resist filling in gaps in summer, either. For the first time, ever, a couple of plectranthus, zinnia, dahlia and cuphea were severely heat affected, but they recovered with a dose of seaweed solution. My only loss so far has been a small fuchsia. I did try to give the plants the best chance of survival by previously mulching, applying a soil wetting agent and using "drought shield". Vinca, begonia varieties and coleus have performed very well.That is great you managed to save those heat-afflicted plants, Margaret! Deirdre

  • By Kerrie 2104 (Zone:10 - Warm Temperate) Monday, 04 February 2019

    Hi Diedre, another great post with lots of plant suggestions to try. I have Tradescantia Sabrina in a pot spilling over a retaining wall. So you don"t find it becomes invasive & smothering at all in the garden bed? Glad to hear I"m not the only one struggling with fungal diseases. My poor Franipanis have been struck down with rust early this year. Usually happens when they"re about to lose their leaves & hibernate so it"s not a problem. It doesn"t seem to affect their flowering though. Tradescantia zebrina does spread to create a mat but it is so pretty and easy to pull up. Frangipani do seem to have rust in Sydney but its good the leaves fall off anyway. Best to put them in the green bin, not the compost heap, as with all plants affected by fungal diseases. Deirdre

  • By Kerrie 2104 (Zone:10 - Warm Temperate) Monday, 04 February 2019

    Reading Magaret"s post I have done the same. I"ve had great success this year with a mulch I got from ANL which is forest fines mixed with a wetting Agent. It"s called Droughtmaster. I"ll definitely use this again. I believe Rocky Point have just brought out a similar product. Sounds a good mulch. Mulch in general really does help our gardens get through these hot summers. Deirdre

  • By Lloyd 4060 (Zone:11A - Sub-tropical) Monday, 04 February 2019

    Tradescantia (learning not to use its legacy name) might be the answer for my patch of heritage fresias on the footpath, usually smothered in weeds after dying back. I dug the weeds out - and pushed some uncovered bulbs back in - and then covered the area in old forest mulch, intending to uncover the patch in winter. But maybe the Tradescantia will do the job - what do you think of these two options? Plus - filled an old barrow with petunias as a mobile colour filler that can follow the light. I find that Tradescantia good for covering the bare spots where bulbs are dormant. I just pull it all up in autumn when the bulbs are due to start appearing. Mulch can be good too. The wheelbarrow idea is a great one! Deirdre

  • By noeline 2081 (Zone:10 - Warm Temperate) Thursday, 07 February 2019

    I agree Sydney has had a rough time....I have done the same with some celosia and cosmos from punnets they are now springing to life....I also planted some coleus I propagated earlier in spring..Thanks for the tip about the arthropdium I was wondering why the leaves were looking the worse for wear this year.... I will be attacking them first thing tomorrow, Coleus are great fillers and I have also found cuttings take root very quickly at this time, even just in a glass of water! Hope your athropodiums are OK. Deirdre

  • By Vikki 2157 (Zone:10 - Warm Temperate) Monday, 11 February 2019

    I just want to say thank you for this wonderful web site. I have so much pleasure from reading and looking at the beautiful plants. Thank you for all the effort you put in. I get so excited when your emails come to me, Thank you, Vikki Thanks so much for your kind feedback! Deirdre

  • By Helen 2770 (Zone:10 - Warm Temperate) Wednesday, 13 February 2019

    Hi I"d like to give a shout out of many thanks to Robin at Epping for gifting me (Helen) with the Iris plants and what I think are orchids. I"d love to have it confirmed please and to know what colour they will be when they flower. Please Robin get back to me through this site as I can not access my hotmail account. None of the passwords I thought I had are working, so I"m in exile. Mary my sister brought them to me today and I potted them up, watered and fed them. Thank you so very, very much.

  • By Robin 2121 (Zone:10 - Warm Temperate) Thursday, 14 February 2019

    Hi Helen the extra plants are crucifix orchids. As with the iris the colours will be a lucky-dip. From memory I took pieces from pink, red, yellow and orange flowering varieties. They will take some time to flower but when established these are tough plants that require little attention and flower over a long period. Plant near brick or rock or in bark or poor soil in terracotta pots in a sunny spot and do not over-water.

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