Choosing and Buying Garden Plants

Choosing plants

Plants for an organic garden need not differ widely from those in any other garden, but there are a number of points to consider.


Diversity

Choosing and Buying Garden Plants - Diversity An organic garden should contain as many different types of plant as possible. Where similar plants are growing in a large area, whether it be a vegetable plot full of cabbages or a border full of roses, a pest or pathogen can build up numbers and soon get out of control.

This plant diversity goes hand-in-hand with creating different habitats: a pond, meadow, dry stone wall and woodland edge  all give you the chance to introduce different types of plants. You can also make more variety in areas such as the vegetable patch by, for example, including some annual flowers and herbs.


Plants for places

Make sure that any plant you choose for a particular spot in your garden is going to like it there. This may seem obvious, but it is surprisingly easy to get carried away by attractive blooms in the garden centres and pictures in nursery catalogues.

Find out what type of soil the plant likes — light or heavy, acid or alkaline, moist or dry. Does it do best in sun or shade? Is it prone to damage by wind or frost? Plants that are put in the wrong place will never thrive and are more susceptible to pest and disease attack. It helps to take note of which plants are doing well in neighbouring gardens. Also check which wild plants grow in woods, commons, and open spaces nearby — closely related garden varieties are likely to flourish.


Resistant varieties

Some plant varieties have more resistance to specific diseases than others, and these are worth looking for if you have a particular problem in your garden. Disease resistance is increasingly a concern of modern plant breeders; for instance, many new roses have been bred to have some resistance to blackspot and mildew. It may also sometimes be worth growing different, but similar, species in order to avoid problems. For example, you could grow the aster Aster x frikartii instead of the traditional Michaelmas daisy, Aster novae-angliae and Aster novi-befgii: it flowers slightly later but is not troubled by mildew.


Food for wildlife

Many garden plants are a good source of food for wildlife: they can provide nectar and pollen for insects and seeds and berries for birds and animals. Try to include at least some of these plants with the aim of providing a “natural larder” over as long a period of the year as possible.


Nectar and pollen

Open and small flowers where the pollen and nectar are easily available will attract the widest range of insects. Most of the old cottage-garden flowers come into this category, but many modern flowers have been bred for size and “frilliness” and are completely inaccessible to insects. Some are sterile so that no pollen, nectar or seeds are produced at all.

Plants in the Umbelliferae family, with their characteristic flat umbels of flowers, are particularly popular with hoverflies, parasitic wasps, and other beneficial insects that have short mouthparts and cannot reach into deep flowers. Many herbs such as fennel, angelica and dill are umbellifers, as are many vegetables — carrots and parsnips, for example. However, the latter are biennials — they only flower if you store the roots overwinter and replant them the following spring. Beneficial insects are also attracted to plants in the Compositae or daisy family that have flowerheads composed of many tiny flowers. Good examples of these are sunflowers, yarrow, and shasta daisies.

Although you will see bees on these plants, these insects have their own additional favourites. Their longer tongues enable them to feed from, for example, flowers in the Labiatae family, which includes other herbs such as marjoram, mint, lavender and thyme. These also attract butterflies, although the best butterfly plants tend to be those such as Buddleias, hebes and heliotropes which have tubular flowers and, often, a sweet scent.

Choose your plants so that there are blooms throughout the season. Those that flower very early and very late are particularly important as they provide much-needed nourishment for insects that are emerging from or going into hibernation. Catkin-bearing willows, flowering currants, forget-me-nots, honesty and wallflowers are rich spring sources of nectar, and herbaceous plants like Michaelmas daisies and golden rod often last until mid-autumn.


Seeds

Many of the same cottage-garden flowers that supply nectar and pollen also produce good seedheads. Do not be too eager to chop off all the dead flowerheads in the border as soon as the flowers have faded. Leave them until seed-eating birds such as goldfinches and greenfinches have had a chance to feed.


Fruits and berries

Choosing and Buying Plants - Chaenomeles Berrying shrubs and trees in the garden supply food for birds and small mammals in autumn and winter.

Again, try to extend the harvest over as long a period as possible. Some berries are inevitably stripped early in the season — mountain ash and the hips of species roses, for example. However, most last long enough to brighten your garden for several months. Even the unpopular berries on skimmias and snowberries will be eaten by birds as a last resort during late winter.

The fruits of the Japanese quince (Chaenomeles) are useful once they have fallen to the ground and begun to soften and ivy, of which the berries only ripen to black in spring, forms one of the most valuable food sources at a time when all other supplies are exhausted.


Native plants

Although pollen and nectar-seeking insects are happy to feed from a selection of garden plants, the same is not true of many leaf-eaters; for them only the native plants on which they evolved will do.

You might not at first want to encourage this sort of insect. However, remember that they are the first step in the food chain which supplies creatures that are both beneficial and a source of pleasure in the garden. Hedges, ponds, wild-flower meadows and woodland-edge shrubberies are an ideal way of introducing native plants.


Nursery plants

It is important to tolerate some pests in your garden, otherwise there will be no food for the beneficial creatures. A nursery plant is one that supports a significant population of pests without any ill effects and therefore acts as a food source to give predators a good start. These creatures can then move out into the garden to prevent damage to other plants.

The common nettle is a good example of a nursery plant. Nettle aphids are among the first aphids to appear in spring and provide food for ladybirds emerging from hibernation . Nettle aphids do not attack other plants.

Many other aphids are specific to their own group of plants, so you can often tolerate them on vigorous ornamentals without fear that they will spread to your crops.


Companion planting

Some ornamental plants are said to make “good companions” to particular fruit and vegetable crops because they enhance plant growth or help combat pests and diseases. Similarly, bad companions have a deleterious effect on each other.

While plants can have various effects on one another — thriving tomatoes cannot be grown near a walnut tree, for example — there are few cases of companion planting that have been researched well enough to give thorough, consistent and practical results. The practice of companion planting is also difficult to fit in with a crop rotation and all the benefits this brings.

However, any mixed planting, such as those that include annual flowers or herbs in the vegetable plot, is likely to be beneficial in some way simply because it adds further diversity to the garden and may attract beneficial insects. The main problem is judging sowing times and spacing so that the yields of crops and the appearance of ornamentals are not adversely affected.

28. January 2011 by Dave Pinkney
Categories: Organic Gardening | Tags: , | Comments Off on Choosing and Buying Garden Plants

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