"Close planting"

Many plants seem to enjoy being planted close together.
Sunday, 17 February 2019     

A thick planting of coleus, shrimp plant and Alstroemeria

I have been pondering lately on the merits of planting things close together in the garden. I have always loved the look of plants merging together like a tapestry and covering every spare centimetre of the ground. This gives the profuse, overflowing effect that I saw and loved during my self-guided Grand Tour of English gardens more than 30 years ago. The creator of Sissinghurst, Vita Sackville-West, wrote about her planting technique as 'Cram, cram, cram, every chink and cranny' (1955), and Margery Fish, in her garden in Somerset, East Lambrook Manor, also practised close planting, believing that 'most plants seem to do better when growing close to their neighbours than in isolation' (1964).

Traditionally, the doctrine was that plants need to be spaced well apart so that they don't compete with one another. However, I have noted, in this horrible hot summer, that the parts of my garden that are the most densely planted are the ones that seem to be coping the best with the challenging conditions. It's possible that the heavy cover of vegetation shades the soil, keeping its temperature lower and helping conserve the moisture in it to some extent. It also means that it is harder for weeds to get a foothold and compete with plants for water and nutrients. Taller plants shelter the lower-growing ones from the harshest rays of the sun, as well as providing wind protection, making a microclimate that benefits the grouping. Shrubs can offer climbing plants support, another benefit of close planting.

In gardening folklore, companion planting has long been talked about, with the idea that particular plants are said to benefit the growth of other plants, broadly or specifically, and suggests a range of helpful plants. Marigolds, for example, are said to drive away nematodes through the release of the chemical thiopene. Garlic planted nearby to roses is said to discourage black spot and aphids. Mint supposedly repels moths and beetles. Nasturtiums are said to lure aphids away from other plants. Some flowering plants - such as Queen Anne's lace, most daisy flowers, alyssum and even parsley blooms - seem to attract beneficial insects such as lacewings that control aphids, thus indirectly helping nearby plants. Whether there is any scientific proof to these claims, I don't know, but these notions do suggest possible advantages of growing plants close together.

Modern thinking about plants is that instead of existing in isolation, they communicate with one another in complex ways, exchanging information, such as warning each other when they are in danger, such as insect attack or presence of pollutants in the soil. Plants even seem capable of recognising their own species and restricting their root growth so as not to disadvantage their kin! Plants are even capable of feeding one another via a vast underground system of roots and mycorrhizal fungi. This is a fascinating area of gardening that I hope to explore more in a future blog, and it does suggest that close planting can potentially be a beneficial garden practice.

In my garden at the moment, robust groundcover plants such as rhizomatous Begonia, Tradescantia zebrina, Pilea cadierei, Crassula multicava, Geranium macrrorrhizum and a number of low-growing Plectranthus are forming thick carpets between and beneath shrubs, interspersed with Tradescantia pallida 'Purpurea' and self-seeding polka-dot plants (Hypoestes phyllostachya) in various leaf colours. Bromeliads are excellent for massed plantings to completely fill in a dry, shaded area under a tree. All these plants are all easy to grow in Sydney's climate and cope well with our increasingly hot summers.

The other advantage of close planting that I have noted is that the dreaded brush turkeys, which seem to have invaded many Sydney gardens in recent times, tend to avoid area which are densely covered, in favour of areas where there is bare soil or mulch between plants, which they thoroughly enjoy scratching about in. I do put metal obelisks over newly planted specimens, as the turkeys seem to sense when earth has been freshly dug, and dig out the plants before they have been established.

 Reader Comments

1/6  Margaret - 2122 (Zone:10 - Warm Temperate) Monday, 18 February 2019

I am of fan of close planting. I believe plants are sociable and enjoy the company of other plants. In addition, plants can support and protect each other, so necessary in this awful heat we are experiencing. Plants entwined present a pleasing picture. Another benefit, perhaps, is that some weeds are excluded! Thanks, Margaret; I do think plants enjoy each other"s company! Deirdre

2/6  Kerrie - 2104 (Zone:10 - Warm Temperate) Monday, 18 February 2019

Well i"m not crazy referring to my plants as " my green babies " then! My garden is only 3 years old & Ive noticed it has coped much better this year now its filled in more. Tell me Dierdre, do you mulch & if so do you mulch over the groundcover? Im going to plant up the Tradescantia zebrina amongst the garden plants in a few weeks when it gets cooler as a have a big pot of it. Thanks, Kerrie. Yes I do mulch -- it can be tricky with these close plantings but I trickle the mulch over the plants and ruffle the leaves so the mulch falls down between the plants. Also with the Tradescantia, I often pull up a fair bit of that in late winter and that gives me more access to the soil to lay mulch. Deirdre

3/6  Brian - 2546 (Zone:10 - Warm Temperate) Monday, 18 February 2019

Just read your blog and saw mention of rhizomatous begonias.I am becoming a great fan of them and wonder if anyone has any they could send me pieces of? Best to go to the Plant Share facility on this website to make this request. Deirdre

4/6  Maureen - 2118 (Zone:10 - Warm Temperate) Monday, 18 February 2019

Great read!! That is what I have been trying to do in recent times and it certainly helps weed control!! Trees talk to each other via root system so surely why not all plants. Yes I do think all plants can communicate with other ones! Deirdre

5/6  Sue - 2074 (Zone:10 - Warm Temperate) Monday, 18 February 2019

I agree as I"ve noticed the stuff that"s crammed in seems to do better in the heat though the toughest in the group sometimes take over a bit. It does give an interesting look as is demonstrated in your pics - a puzzle to solve (even though you have given us the answers:-) Like Kerrie I have things on hold - in fact the kitchen bench has lots of cuttings developing good roots. - Hopefully it will be planting weather soon! Thanks, Sue. We seem to be having better weather this week now -- it will be good when we can get back into gardening again! Deirdre

6/6  Valerie - 2121 (Zone:10 - Warm Temperate) Monday, 18 February 2019

Love your close planting combinations. I"m attempting the same, initially to repel turkeys. Now I know that its helpful to the plants themselves I"ll expand wherever possible. The Trad.Zeb. looks great wherever it goes. I"m mixing it with the dark purple one and some Plectranthus. I see from your pic that Coleus would look good too as well as the polka dot. I keep digging these out of the grass and putting them back into the garden. Bring on the cooler weather so we can get some planting done! Thanks, Valerie. Hopefully this cooler run of weather will continue for a while and that we get some decent rain with it. Deirdre

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