GARDENS: Jane Powers rediscovers some home truths that have made life easier in her garden.
Where does soil come from? Why do some plants have big leaves? What do flowers do? It was a while before I worked out the answers to these fundamental questions. Or rather, to be honest, it was a while before I even thought to ask myself them. When I started gardening, as a small person, more than 30 years ago, I bumbled around optimistically, shoving seeds into the soil, fully expecting them to grow into fine, healthy plants. My queries, therefore, were more in the egocentric vein of "where did my lettuces go?" (answer: slugs had them for breakfast) and "why won't anyone eat my radishes?" (they didn't like their woody texture, nor the larvae that tunnelled through the roots that I'd harvested too large).
The immediate concerns of new gardeners today are not greatly different, of course. But the information available to them is a world apart from the largely dry and unpalatable stuff of my youth. Now any gardening book worth its salt makes sure to unravel the mechanisms and mysteries of plants and soil right at the start. And this is a good thing, because the sooner we ask ourselves what is the soil, why certain plants have big leaves and what's the point of flowers, the better gardeners we'll be.
A new Royal Horticultural Society book, Learn to Garden, aimed at the absolute beginner, has reminded me of the usefulness of grappling with these basics. Written by experts, it's full of basic principles and sage advice - and how I wish I'd had it when I was digging my first ham-fisted seed trenches. I can't present a complete inventory of gardeners' home truths here, of course, but I can offer a half-dozen, evoked by the book, that have helped me in my gardening life.
THE SOIL IS ALIVE
Soil is composed mainly of bits of rock and organic matter. The latter includes decayed fragments of old plants, but, more importantly, it also includes living organisms: bacteria, fungi, minuscule plants and microscopic creatures. A quarter-teaspoon of healthy soil may contain a billion living things. These beings mill around in a complex interdependent society, eating old plant matter (and each other), crushing rocks, reproducing, dying and adding to the soil's humus. Their presence makes the soil fertile, aerates it, helps it hold water and makes it a living, elastic fabric. Soil takes thousands of years to form, so be nice to it.
LEAVES HAVE BEEN PERFECTLY DESIGNED BY NATURE
Plants' leaves have evolved in response to their environment. The greener the leaf, the more chlorophyll it has, allowing it to absorb more light. Shade plants, such as hosta, often have large dark-green leaves, to make up for the lower light levels. Plants suited to bright spots, such as lavender and rosemary, have smaller leaves, which need little water, or they may be covered in hairs (verbascum), to prevent moisture loss. They often have a grey or blue hue, which reflects excess light. Some sun-loving plants, such as sedum and agave, have succulent leaves that act as reservoirs. The shape and colour of a plant's leaves dictate where you should place it in the garden.
A FLOWER'S JOB
Let's call a spade a spade. A flower's sole purpose is to have sex for the plant. Its anthers are the male parts, the stigma is the female bit. Sex happens when pollen from an anther, usually borne by an insect, the wind or gravity, meets a stigma. The eventual product of the union is seeds, contained in fruits, pods or other receptacles. This pollinating and seeding activity is desirable when the plant is one that we grow for fruit - tomatoes, apples or beans, for example. If the plant is cultivated for flowers or foliage, however, then the setting of seeds is not so favoured. When a plant begins to make seeds it thinks that its work is nearly done and that it is time to quit until next year, in the case of a perennial, or die, if it is an annual.To keep plants flowering, it is necessary to deadhead them (remove the spent flowers) and thus prevent them making seed. A plant will often flower prematurely if it is stressed and thinks it's going to die, so it's important to make sure it is getting enough food and drink. This stress-induced mechanism can be seen in lettuces and spinach that bolt if they don't have enough moisture.
WATER WISDOM
How we deliver moisture to a plant can affect its health and growth. It roots naturally grow to where the soil holds water. If we hose the soil frequently, water is delivered at the surface, and the plant makes shallow roots - not a good thing, as it has no defences against drought. Far better (and more conservation minded) to forget the hose and encourage a plant to grow deep roots, which will seek out moisture in the parts of the soil that never dry out. To increase a soil's water retentiveness, add organic matter (compost or well-rotted manure) when planting, water really well and cover the surface with a mulch of more organic matter, gravel or other material. Beds and borders can be mulched in spring, when the soil is wet. Don't mulch dry soil, as this will prevent water from soaking in.
APICAL DOMINANCE
The chemistry of almost all plants' growth is controlled by the buds at the tip of its shoots. These apical buds contain chemicals that inhibit the growth of all the other buds, lower down the shoot. When you snip off the apical bud, the other buds get a shot of heretofore-denied energy and start to grow. A simple action such as pinching out the growing tips of your geraniums, to make them bushier, demonstrates this principle. All pruning procedures, no matter how complicated, rely on the rule of apical dominance.
KNOW THE GOOD GUYS: THEY'RE ON OUR TEAM
Gardening may seem as if it's a solitary activity. It's not. For every lone human toiling in the soil, there are billions and billions of other creatures. Not just the soil-dwelling critters mentioned above but also all the other things that fly, crawl, scurry and slither about the garden. A few of these can be considered pests: aphids, vine weevils, slugs, snails, sawfly, leaf miners, eelworms and so on. But by far the majority of our fellow gardeners are benign. Many are predators that will save us the bother, time and expense of waging the pest wars. We should therefore welcome these good friends: birds, bats, frogs, newts, ladybirds, hoverflies, lacewings, ground beetles, spiders and centipedes. Even wasps are voracious eaters of aphids. Earthworms do our digging and bees, of course, help the flowers have sex.
Learn to Garden is published by Dorling Kindersley with the Royal Horticultural Society, £18.99 in UKONE FOR
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