Container gardening – mediterranean style
Many Algarve gardeners do not have the luxury of a garden and are confined to growing plants on a balcony, paved courtyard or a roof terrace – so container gardening offers plenty of scope and pleasure.
There is a multitude of plants that will grow successfully in pots or small raised beds – sub-tropicals like Hibiscus rosa-sinensis (Chinese Hibiscus) from Asia and Brunfelsia pauciflora (Yesterday, Today and Tomorrow) from Brazil. But some true mediterranean plants can survive quite happily and many of the native bulbs can be enjoyed each spring if kept in pots.
Even those of us with gardens will usually have some potted plants – things which need to be moved to a protected place in the winter, or rather special plants which we are afraid might get lost in the garden. Any greenery will also attract birds and some wildlife for an extra bonus.
Terracotta versus plastic: terracotta pots look nicer and ‘breathe’, but plastic pots are much lighter when weight is a consideration on balconies and roof terraces. Plastic pots retain more water, so do not swamp them and always allow for drainage. Good drainage comes by raising the pots on two bricks or using pot stands. A recommended planting method is to put a layer of textile in the base of the pot – old shade material or sacking is best – and then filling with soil. Always choose the size of pot that fits the plant roots; in other words, don’t over-pot by putting small plants in large pots. Avoid pots with a ‘waist’ or rounded sides, as re-potting will prove impossible without breaking the pot.
For most plants, any good general-purpose soil/potting mix is suitable. Bear in mind that any composts with a lot of peat in them don’t absorb water once dried out. Peat is in any case an unsustainable product and should be avoided. Match the soil/compost to the plant, using acidic or neutral as needed, for instance for camellias.
This will depend on exposure (full sun, partial shade, shade) and the conditions (temperature, windy situations). More plants die from over-watering than from under-watering. Watering by hand has the advantage that you can assess each plant’s needs individually. Whether by drip irrigation or by hand, always water early in the morning or in the evening. Avoid spraying foliage as cal from hard water builds up on the leaves.
If plants have been in a large pot and you don’t have the space to use an even larger pot, you can remove the bottom third of its roots by simply sawing through them, and then return to its original pot with some fresh soil at the bottom. In this case, to help the plant recover, remove at least a third, or even more, of its top-growth. You can repeat this treatment every two or three years.
In hot sunny conditions, plants do best when their pots are placed close together as this provides some shade and atmospheric moisture. If possible, move the pots further apart in winter to allow air to circulate.
Regular watering of pots leaches nutrients out of the soil. A dose of a balanced fertiliser given every 10 days or so during the growing period from late spring to early autumn promotes good growth and flowering. If a plant shows signs of chlorosis (yellowing leaves), give iron: water-soluble iron for plants is available. But check first that the leaf-yellowing is not due to over-watering.
Aphids will usually disappear as the summer advances. In bad cases, cut off and destroy affected shoots and/or spray with a soapy solution to which a few drops of pharmaceutical alcohol are added. Good air circulation also helps. Scale insects, both the kind with a hard shell and the soft white squishy ones: pick them off by hand and destroy. Where woody stems are affected, wipe the stem with cotton wool soaked in alcohol. This treatment does not solve the problem completely but keeps it under control. Remember to check the undersides of leaves.
For woody plants, try oleanders, lantanas and fuchsias. Scented climbers such as jasmines and the vibrant Campsis, Pandoreas and passion flowers make great plants for height. Don’t forget small winter- and spring-flowering bulbs, which can be left dry in summer, with their pots perhaps moved to a shadier corner and protected from cats.
Pelargoniums are always good value – the ivy-leaved trailing ones withstand hot sun best. There are also some lovely species from South Africa which are tough and pest resistant, such as P. acetosum.
Also, many kitchen herbs: mint, chives, parsley, among others, and a whole range of vegetables such as tomatoes, peppers, chillies and aubergines can be grown in containers for the summer. The smaller citrus varieties look lovely in pots and you can give them the water and nutrients they need. Kumquats and calamondins do especially well.
Use succulents such as Graptopetalum, Aeonium and Echeveria in bowls and pots. Mixing the various steely grey, bronze and silver colours can make a lovely show and be very drought resistant. Do not forget that some succulents can get sunburn, so partial shade gives the best displays.
Many typically Mediterranean plants such as lavender are not suited to cultivation in pots. In their natural habitat, they develop deep woody roots to survive the summer drought and do not need or want water. The restriction of a pot prevents the plant from making its deep roots. No plant in a pot can survive the summer unwatered, so for those plants that don’t want water, it is hard to find the right balance – giving just enough for the plant to survive but not enough to kill it.
Containers give us the chance to try new plants and, on hot summer days, planted containers near to the house can give a lot of colour and interest. If all else fails, even an empty pot can give some drama to an empty corner – it is always worth experimenting!
By Rosie Peddle
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Mediterranean Gardening Association – Portugal