Architectural Plants. Christine Shaw

and in peak condition.

      A genuine Versailles planter costs a small fortune, but there are some good replicas on the market. Before you buy, check first that they have removable sides, otherwise they rather miss the point.

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      Versailles pots with removable sides allow root pruning to be done with ease.

       Choosing plants for pots

      Seasonal plants such as Canna, Zantedeschia, Agapanthus and Hedychium that die back each year after flowering can all live in pots for years. Once they become too large for their pots, haul them out, divide the clumps into several plants, replant what is required and give the rest away to a gardening chum.

      However, the idea of buying a splendid new pot, often at considerable expense, is usually for it to be a permanently planted focal feature, looking attractive all year round, not for just a few months in the summer.

      Plants that never get any bigger are ideal. Box (Buxus) balls, bay (Laurus nobilis) lollipops, yew (Taxus) cones and Japanese pom-poms such as Ilex crenata are perfect, as long as they are clipped regularly to keep them in shape. During the growing season, clipping must be done little and often so that the foliage doesn’t become straggly and unkempt. If the foliage is allowed to grow, more stress is put upon the root system as it struggles to support the extra leaves.

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      Zantedeschia aethiopica ‘Crowborough’ can live in a pot for years if it is well watered.

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      Japanese topiary such as Ilex crenata are blissfully content in large terracotta pots.

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      Slow-growing plants like Trochodendron aralioides are happy to spend the first four years of their lives in containers.

      For something a little more unusual, try the silver-leaved Corokia x virgata from New Zealand or the dense form of Euonymus japonicus ‘Compactus’.

      Another category that contains some interesting choices are those that are very slow-growing and evergreen. There really is little point in choosing anything deciduous: nobody wants to look at a pile of sticks in the winter if the container is in a prominent part of the garden. The Dwarf Fan Palm, Chamaerops humilis, is happy in a pot for years. So is the dwarf Pittosporum tobira ‘Nanum’. This lovely glossy-leaved plant has highly scented flowers in the summer and can be grown in a pot quite easily. Tree ferns such as Dicksonia antarctica are happy enough, too, as their root system takes years to outgrow a large pot. Hebe rakaiensis is another good choice. This plant grows to a 90cm (3ft) mound and then stops, although clipping is still advisable to keep it extra tidy. Consider a rare tree as well: Trochodendron aralioides is slow-growing, tolerant of neglect and essential for any gardener wanting to grow something really unusual.

      There is also a wide range of small succulent plants available, all of which are quite content to sit in pots. Try Aloe aristata, Echeveria glauca, Aeonium arboreum and the purple variety Aeonium ‘Schwarzkopf’.

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      Euonymus japonicus ‘Compactus’ is an unusual leafy choice for a pot.

      Finally, there are the strongly architectural spiky plants. Most of these come from desert regions, which mean they have had to adapt to burning hot sun during the day, freezing temperatures at night and long periods of drought, making them admirable choices for containers. Most hardy Yucca suit this purpose for the first few years of their lives, especially Yucca gloriosa and Yucca aloifolia. The wonderfully spherical Dasylirion acrotrichum can live in a pot for years. Probably the most spectacular of all is Agave americana. This plant and its various coloured forms all look stunning in terracotta pots.

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      Agave parryi and most other desert succulents almost enjoy being in pots.

       Compost

      With the exception of tree ferns, which require a peaty compost, most plants are blissfully content in a loam-based compost, such as John Innes no. 3. Stir in up to 50 per cent of extra grit to provide really sharp drainage. This eliminates the need to fill the bottom few inches of your pot with large crocks as we are often advised to do. Loam-based compost is heavier than a peat-based mix, which helps to stop pots blowing over in the wind. It also has more nutrients and is easier to re-wet if the whole pot dries out.

       Feeding

      Plants in pots need all the help they can get, and this includes regular feeding throughout the growing season. In spring, start off by giving each pot a good dollop of something strong, such as a mix of blood, fish and bone. Thereafter, add a small dose of foliar feed to each watering can and use every time you water, even if it’s every day. Vital nutrients are easily leached out of pots, leaving plants prone to yellowing. The aim is to have handsome foliage that looks in the peak of health, not jaundiced and miserable.

       Watering

      The all-important task of irrigation must be taken seriously. The compost should never be allowed to dry out completely, which is quite an onerous task in the middle of a heat wave. Having pots within easy reach of a hose helps, so does having a garden tap. Plants in pots need watering virtually every day during the summer months, so careful planning is needed. Don’t wait for the summer to realize that each plant is a long way from a water supply – carrying heavy watering cans soon becomes a chore.

      Alternatively, think about installing an automatic drip-irrigation system. Each pot has the recommended number of ‘drips’ pushed into it, all of which are connected to a long length of tubing plumbed into the water supply. The timer is then set to come on for as long and as often as you wish. The cost of these irrigation systems has decreased considerably as their popularity has increased, and they are now available at all good garden centres. Most are now fairly easy to install without expensive plumbing costs.

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      Plants such as Azorina vidalii can stay glossy and healthy-looking if fed and watered correctly.

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      With regular irrigation, Cycas revoluta can look fantastic in a pot.

       Pests & diseases in pots

      Plants in pots are much more prone to attacks from various beasts and general disorders than plants in the ground. Keep a constant watchful eye and catch them at the first sign. (See the chapter on pests, diseases and other disorders on pages 334–347.) One particularly nasty horror is the dreaded vine weevil. This sneaky, vicious brute lurks under the soil feeding on the roots of your precious specimens. One day, your plant collapses with no warning and the top