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.