Understanding the root structure of plants and trees is one of the best ways to ensure proper planting and creative landscaping in your garden.
Xanthe White Photo: Supplied
Landscape designer and gardener Xanthe White tells Nine to Noon planting at the right time is essential if you are establishing a garden or adding to it, but not all plants are the same and will benefit from some individual attention.
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Another factor is climate warming and increasing seasonal variations, she says.
Recent humid weather this summer saw her banana plants thrive in her garden, with large yellow ripe fruits proliferating, when in past summers this hadn’t been the case.
“We had different ways of cooking them up, but I actually didn’t know what I was missing out on until now,” she says.
“That change in terms of our climate means we have to understand our seasons and observe our seasons and those shifts and how we’re going to work with them. So, one of the most important things with gardening is not what to do, but understanding of how the plants work.”
She says one of the things she sees a lot is the issue of understanding root structure, soil and how best to plant out.
There are key things to think about before planting, White says.
“Those seasonal shifts are probably the most critical thing we need to consider. We can plant any time if we’re willing to put our hoses on and water and mulch and look after them.
"We can get planting any time and there are circumstances where with barren dry earth it’s much better to get what we call green mulch, living things over that soil to avoid transpiration and losing the quality of the soil. So, it’s not that we can’t plant, but when is the best time.”
We need optimum conditions where temperatures are dropping, water table is rising and you can guarantee that those plants are going to go into the ground with natural consistent water supply and without intense heat.
That will vary across the country.
“What you’re looking for is that dampness in the soil returning. Essentially you’re waiting for those water reserves that sit underneath our soil to cool the soil down and provide that dampness you need to get the plants growing.”
Another issue when planting is putting the soil over the stem, which causes rot around the stem, or planting plants too ‘proud’, which exposes the roots.
“When we define what grows under the ground, one of the key things is to learn stems, which we associate with growing above the ground and roots, which we associate with growing below the grind, you can have stems underneath the ground and you can have roots above the ground.”
Aerial roots of pōhutukawa trees are an example of roots above, and bulbs like daffodils are an example of stems being under the ground. The stem is what sends up leaves, flowers, branches and then fruit once the tree has enough carbon through photosynthesis, and roots draw up the water and nutrients.
“That’s why the timing of planting is absolutely essential in a garden because if those roots establish well and lock into that water system, significantly over this period of time they’ve got the longest most consistent period of water to which establish those lovely structures going in.”
It will make the plants more resilient giving it a firm root foundation and structure, which means the top growth is going to be beautiful, she says.
Planting Photo: supplied by Xanthe White
One of the common types of stem that grow under the ground is a rhizome, which can be a major weed issue in the garden.
“The plant that encapsulates the rhizome best is kikuyu grass and it runs along the ground. We all know the kikuyu goes up into our veggie gardens and tries to scramble up trees or anything that gets in its way. We know if we cut those rhyzomes it sends down little roots into it. If you we look at it that root actually has leaves growing out of it.”
Understanding how plants grow structurally enables gardeners to handle them with care and ensure these have optimal situational conditions to grow.
Bulbs, for example, have a growing stem that dies down and hides from the cold in winter and can be moved when dormant. Bulbs are the stem of the plant and the root comes from the base of the bulb.
A tuber can form from a stem and a root. and understanding this allows you to produce bigger crops.
“This explains why we mound the soil up over our potatoes, because our potatoes don’t grow from our roots, they grow from the stem, which makes them a tuber. Whereas, kumara grow from a swollen root, so we call them root tubers.”