Pots, troughs, tubs, urns, vases, hanging baskets, window boxes and even growing bags can all be used to convert a good garden into a great garden. The first five can be positioned on any hard surface. Hanging baskets and window boxes, by definition, should be attached to buildings or vertical walls. These will raise the colour level, but you must ensure that salt-tolerant plants are chosen.
Getting the best from containers
Planted containers are at their most dramatic when used for seasonal displays of tender annuals (mainly bedding plants) and bulbs. When in full flowering glory, they make wonderful focal points. They are, of course, ideal for standing on a patio, path, driveway or next to a door, but they can also look very good when stood in borders. When plants in a tub are at their prettiest, the tub can be situated in a dull border and raised slightly on blocks. For a month or two, it can transform that part of the garden.
As we saw in the last chapter, where soil is poor, containers can be used to great effect, and they allow a wider choice of plants to be grown. Permanent plants such as small trees (dwarf fruit trees can be very successful), conifers, flowering shrubs and even some perennials can look fabulous in containers – although they do not necessarily have the long summer of vibrant colour that you can get with annuals and bedding plants.
The main pitfall of containers is in the planting and maintenance of them. With the exception of vegetable plots and bedding displays, most areas of the garden need planting once and can then be left for a long time, often many years, before they need replanting. Flower containers require planting up on a seasonal basis. This can be minimized if you are growing specimen perennials, shrubs or trees in the containers, but even then it is often desirable to grow some temporary colour in and around the base. Then there is the maintenance of the containers – and this really comes down to one thing: watering (see page 87).
Lastly, in a coastal garden, you must also take account of the wind. In very exposed conditions, it is a good idea to weigh down containers by placing rocks or bricks in the base before potting, or putting heavy stones on the surface if high winds are forecast.
Materials and styles
Containers can be made from wood, terracotta, reconstituted stone, moulded resin and plastic.
The latter are the cheapest and can be rather garish so choose what you want carefully.
Wooden containers can look very good and fit well in a coastal garden with decking or other whitewashed and maritime themes. But as with wooden furniture (see page 38), the wood used in containers may be prone to rotting caused by the constant salt-spray.
Terracotta containers can look wonderful in a Mediterranean-style setting. Check when buying them that they are frost-hardy, otherwise even a few short, cold spells can be sufficient to cause the clay to splinter into fragments.
In the case of hanging baskets, wire is the traditional type used; the soil within is kept in place using a basket liner. Sphagnum moss can be used for lining baskets, however, harvesting sphagnum from a natural habitat can harm indigenous wildlife, so it is better to use fabric liners in green, brown or black, which do the job just as well. If you do use moss, make sure that you line the basket discreetly with polythene as well, otherwise both the moss and the compost can fall out, especially if helped by visiting birds wanting to supplement their nests.
Plastic baskets are also available. These have filled-in sides and in many ways they are easier to manage. To start with, they dry out less quickly,
and some types have a built-in water reservoir or tray to make the chore of watering less frequent. The basket you choose should have holes in the sides in order for trailing plants to be positioned.
Finally there are window boxes. Traditionally these were always of solid wood and very often made bespoke, for whichever window they were to adorn. Mass-produced plastic window boxes are cheaper, lightweight and available in various sizes; you can also buy sets consisting of the box, a water tray to avoid dripping and the all-important brackets for fixing to the wall.
As mentioned earlier – but we will reiterate it anyway – containers of any description should be anchored or weighted if they are likely to move in high winds. With hanging baskets and window boxes this is particularly important as, if they fall from a height, they can cause considerable damage. Brackets should be checked for stability and strength regularly.
When planting hardy plants into a container, it is a good idea to get the container into its final position before you start. This saves having to move it after it is planted, when it will be very heavy. If it is springtime and you are planting tender subjects for a summer outside, you may wish to do the planting in a greenhouse or shed, and to keep the planted container under cover for a week or two. This will give the tender plants time to establish and become stronger, and it will also allow time for the weather to warm up. Gradually acclimatize the plants to outside conditions, particularly if you will be placing them somewhere that is exposed to wind.
Planting pots, tubs, urns and vases
Start by putting some coarse material, such as broken flowerpots, pea gravel or washed stones, into the base of the container. You do not want to completely block the drainage hole in the bottom of the pot (and if there are no drainage holes, then you should drill some), but you do need to allow excess water to be able to escape.
Fill the tub two-thirds full with compost, firming it as you go. Use a loam-based compost, as this is longer-lasting than peat- or coir-based composts. These latter types will do quite well, but they are prone to quicker drying in warm weather. Check whether the compost has slow-release fertilizer added to it – many new brands of shop-bought compost have this included. It gets your plants off to a good start, but you will need to supplement the feed during the growing season. If there is no fertilizer already incorporated, you should add your own at this time.
A consistently moist compost throughout the growing season is important, for if compost is allowed to dry out the plants will not be able to suck up what they need to survive (let alone thrive). Water-retaining gels are being used more these days by environmentally conscious water-saving gardeners to solve this problem. They are sold as dry polymer granules, which are mixed with the compost at planting time; some composts now include granules as standard. These granules absorb moisture and turn into a gel, swelling to many times their own weight. They release moisture to plants over many months and even seasons. Plants that benefit most from such gels are those that grow rapidly and are planted in light, open compost, from which moisture quickly evaporates.
The best plants to put into a tub already come in pots. Remove the pots and set out the plants in the tub where they are to go. As a guide, placing one plant in the centre and four or five around the edge of a tub 12in (30cm) across is about right. Set each plant so that the surface of its root ball is 1in (2.5cm) below the rim of the tub. Fill around the root balls with more compost, firm gently and water well.
Throughout the growing season, and longer if you have potted up shrubs or perennials, you will be able to add temporary colour in the form of bedding plants, annuals and bulbs. This means that you can have the same permanent planting from year to year, but the supplementary colour can change on an annual basis. This makes for an interesting and ever-changing garden.
Planting hanging baskets
Start by making sure that your basket is stable. Use the chains to hang it from a greenhouse support or wall bracket, or remove them and place the basket to sit within the rim of a large pot.
Place the liner in the basket, making sure that it fits snugly, then put a circle of plastic in the base to act as a water reserve. Begin filling your basket with compost; if your basket allows you to plant through its sides, only fill it halfway for the moment.
The taller plants should be placed firmly in the centre, to create a good structure. Put some trailing plants in the sides; cut holes in the liner if there aren’t any, then push the rootballs through the hole from the outside, pulling them through gently.
Some composts have feeds added, which last just a few weeks (check the packaging) – these will need liquid-feeding later in the season. If your compost does not have feed in it, add slow-release fertilizer. Add some more of the compost, then the small plants can go in. Give the basket a good water to settle in the plants.
Until the basket is ready to go outside, it is best to hang it in a greenhouse, a warm, well-lit conservatory or a bright room.
Planting window boxes
The process of planting a window box – which should be carried out after the box has been put into position and secured – is similar to that of the pots and tubs discussed on page 84.
Smaller and trailing plants are particularly appropriate to window-box schemes. Permanent plants, such as shrubs and perennials, are less successful in window boxes because they tend to get rather large and are usually only at their best for a short period. When these plants are not in season, the window box will not be very attractive.
Mostly when you see such woody plants as variegated ivies, heaths and heathers (forms of Erica carnea), Euonymus and other evergreens, and dwarf conifers, they are used more as temporary infills of foliage, particularly during the winter months when there is less colour to be had with flowering plants. These woody plants do not mind cold winter temperatures and are usually fine even in exposed coastal situations.
Watering plants in containers
During the warmer months, container plants need checking daily for water requirements – even twice daily in very hot weather – as they can dry out rapidly. Hanging baskets, especially, are notorious for this. Potted plants need watering all year round, except in freezing conditions. In winter, the rain may do it for you, but keep checking because foliage can act like an umbrella, or a wall can create a dry spot. It is best to water in the early morning or evening when evaporation rates are at their lowest.
By mid summer, hanging baskets are full of plants and use a lot of water. Even worse, they tend to hang by sunny walls, and the heat that the walls reflect makes them dry out even more. So anything that you can do to keep them moist is worthwhile.
Use the retaining gels in these for a constant supply of moisture. Use rainwater from a tank or water butt for irrigating mature container plants, but use tap water for seedlings and young plants, which are more delicate and more prone to infection from the impurities and bacteria present in rainwater.
The best way to water is with a watering can fitted with a rose spray, which distributes water evenly. If you do not have a rose spray, place a piece of slate or old crock in the corner of the container, tilted downwards, and gently pour water on to it. This method prevents soil compaction and gives an even distribution of water. Ideally, repeat this in each corner.
Hanging baskets are notoriously awkward to water – and cause sleeves and arms to get wet in the process! It’s worth investing in a special extension hose and hooked watering lance so that you do not have to hold up heavy watering cans. With these you will also be able to direct water more easily to where it is needed.
Automatic watering systems are available but expensive. However, they are very effective and water-efficient, and can be regarded as essential if your garden-by-the-sea is a second home or holiday home and you are absent for long periods. You preset the times when you want the system to start and stop, and in the more sophisticated versions you can even determine how much water should be used. It is a good idea to make sure that the system is working properly even if you are away – ask a friend or neighbour to look in to check. Failure of the system could mean an expensive array of dead plants on your return.