Choosing and Planting Shrubs
Choosing and planting shrubs
Shrubs can be obtained in several different ways: from the specialist shrub nurseries by ordering, in sealed packs from supermarkets and chains of larger stores and from garden centres. They can also be ordered from the internet – there are an ever growing number of internet based garden suppliers as well as larger garden centres who provide an internet service additionally.
Ordering from a nursery
Until the late 1960s, the only way to buy shrubs was to place an order for them in spring or early summer, about six months before planting. This was because the nurseries started lifting their plants from the end of September onwards, to send them out through autumn and early winter so that the customer could plant them before really cold or wet weather arrived after Christmas, and while the soil was still comparatively warm from the summer.
Shrubs are also available in sealed polythene packs at supermarkets, chain stores, and DIY centres. Plants for these packs are lifted, shoots and roots trimmed, leaves removed (to prevent water loss from the pores or ‘stomata’ of the leaves), roots wrapped in moss and polythene and the whole plant sealed into a polythene wrap, so that it remains fresh for a long time. The pack is convenient to handle and carry, and if the ground is not quite ready for planting, the plant can be left in its wrapping without having to be ‘heeled in’ to await planting.
A third method available is that nurseries sometimes grow their shrubs in disposable containers. The plant suffers a minimum of disturbance, planting can be undertaken at a time convenient to the buyer and, provided it is done carefully and the plant given the appropriate aftercare, can be carried out at any time of the year, except obviously under extreme weather conditions.
PREPARATION OF SOIL
You might wonder why it is that plants have roots and grow in soil at all; in fact in some tropical countries they grow on the bark of trees, or in mountainous districts on stones where there does not seem to be any soil. However, the answer lies, not in the soil itself, but in the plants’ method of feeding.
Although green plants get the bulk of their sustenance from the air in the form of carbon dioxide, they also need other substances, and these are usually called the plants’ food.
In the case of most plants grown in this country, they get their food and water from the soil. Not only this, they must have most of their food in liquid form, and this is provided in the form of dissolved substances in the soil moisture. This moisture is absorbed into the plants’ roots by a special process known as ‘osmosis’ and will only work if the liquid already in the plant contains more dissolved substances — not necessarily the same ones — and is more concentrated than the liquid outside the roots. If the reverse happens, and the soil moisture is more concentrated, the liquid in the roots is drawn out, the roots become dried up and do not work properly, and liquid in turn is drawn from the part of the plant above the ground to replace that lost from the root. The process goes on until eventually the leaves begin to show signs of drying up, or desiccation, which in its extreme form takes the appearance of browning round the edges of the leaves and withering.
This is why it is so important, when feeding plants — particularly with concentrated ‘artificial’— not to apply more than the recommended quantity.
Another reason for planting in soil, at any rate in this country, is that it serves as an anchor for the plant. It is possible to grow a good many plants in a solution of liquid nutrients only, but they will always require a support of some kind if this is done.
It should now be much more apparent how important the roots are, and how vital it is that they should be treated correctly when planting, and also how necessary it is that the soil is prepared properly beforehand.
There is another point which is of importance when considering soil, and that is what is known as its structure. The way in which the soil particles stick together, and what these particles consist of, is of great importance in determining whether a soil has a poor or a good structure. One in which clay particles predominate is known as a heavy soil, if only because it tends to retain water to a very considerable extent, and it may be grossly lacking in air.
A, on the other hand, is loosely put together—the chemical nature of the grains of sand is such that they are easily separated, so that water drains quickly through the soil taking plant foods with it.
There are soils containing sand and clay to varying degrees between the two extremes, and the ingredient which helps to modify them to a certain extent is ‘humus’. This is rotted organic matter, such as, , or anything of a vegetable or animal origin. Humus helps the sandy soil to retain water and food; conversely, in the mainly clay kind, it improves the air content and alters the way in which the clay particles are bound together so that water is able to drain through it satisfactorily.
One essential point to remember, when deciding where to plant shrubs, is to allow sufficient space for their ultimate height and spread, whether they are planted singly in borders with other plants, or grouped together in their own borders, or singly in grass. It is heartbreaking — and can be backbreaking too — to have to dig them up and transplant them after a few years, because they are crowding everything else out or are doing badly from lack of room.
By then it is more than likely that all the available space has been filled in, and the ruthless destruction of the shrub, or some other plant, is necessary. Do make sure of their height and spread first, and allow space accordingly. If this means large empty spaces for a while, they can always be filled in with , or herbaceous with short lives, or with and .
If possible, the place where the shrub is to be planted should be dug over to a depth of one spit (one spade deep) and the bottom of the hole covered with a layer, about 3 inches deep, of well-rotted compost, farmyard manure or leafmould. This is forked up and mixed with the soil at the bottom of the hole which can then be left, if need be, for a little while. Make sure thathave been carefully and thoroughly removed.
When the shrub arrives, have a good look at the roots, and if any are broken, cut them so that they end cleanly and not in a jagged finish, which might rot or become infected with a soil disease. Do the same with the top growth, cutting back any broken or dying shoots to just above a leaf joint. The inside of a dead shoot is brown when the bark is scraped away with the thumb. If the shrub needs a support, and they mostly do while they are getting established, put a stake into the hole first, making sure that it is quite firm.
It is a good idea to have somebody to help with planting, if only to hold the shrub in position while the soil is replaced around it. A shallow mound in the centre of the bottom of the hole enables the roots to spread out more easily and point slightly downwards, which they would do naturally. Spread the roots out so that they extend comfortably to their full length, and put the plant in at such a depth that the soil-level mark stained on the stem from the time it was growing in the nursery is level with the top of the hole, and then add soil mixed with more compost or, shaking the plant at intervals, so that the soil particles filter down between the roots. Do this until the hole is half full, then firm it with the heel and add more soil to bring it up to the level of the surrounding ground. The addition of a little bonemeal, about a handful, thoroughly mixed with the soil when planting, will help the roots to get going.
Tie the shrub securely to the support but not so tightly as to constrict the stem; a piece of sacking round the stem will protect it from chafing. Allow for slight sinking of the shrub as the soil compacts. Tidy up the surrounding area, and rake over the topsoil lightly, so that the surface is broken up. If smooth, this tends to prevent the water seeping down, and encourages the growth of moss. If planting in a lawn, make a small square or circular bed round the shrub and keep this free of weeds while the plant is getting established.
If planting evergreens orin the spring, dry weather or strong cold winds could occur. This results in rather a pronounced loss of moisture. As the foliage is still on the plant, it will be losing moisture by ‘transpiration’ through the stomata, at a time when the roots are not growing and absorbing liquid, so it is advisable to spray the top growth over every day, with water, in order that the stomata may remain closed and prevent this loss of moisture; also one should make sure that the soil is really moist deep down as well as on the surface. A special compound is available to spray on to the leaves which seals them so that transpiration does not occur. This eventually washes off and does no harm to the plant, and some shrubs are in fact sent out with this already applied.
Watering in the average shrub after planting is unlikely to be necessary, except where the soil is already dry, when heavy watering beforehand, and regular watering afterwards while the weather remains dry, will be required. Never plant in dry soil and make sure that the ball of soil round the roots of plants from pots or other containers is thoroughly moist before starting the planting operation.