L01E - Gardens

(Comparison of gardens in northern Europe and Portugal) 

Soil chemistry and geology 
The soils in Portugal range from the rich volcanic soils of Madeira to the thin acid soils of the Alentejo and the alkaline sandy soils of the Algarve coast. In the areas with a hot and dry summer climate; the sun seems to bake dry the organic material which is then lost to the soil. As a result, many of the soils in the coastal Algarve and the Alentejo are very poor in organic matter, but plenty of compost and mulching can work wonders. Serious gardeners who really want to know their soil may contact the local agricultural services or have samples analysed by the regional laboratories of the Ministry of Agriculture. 

Climate effects 
In general the climate in Portugal is warmer and dryer than northern Europe, and it suffers long periods of drought. Continental Portugal has a climate similar to southern California, South Australia and the Cape in South Africa. It has relatively little frost (except further inland and in the hills), so plants requiring cold to trigger a rest period (like apples and rhubarb) do not grow well in most places. On the other hand, the lack of frost allows semi-tropical and Mediterranean varieties to grow well. The almost complete lack of rain during the hot summer will kill plants that are not heat and drought resistant unless they are well watered. 

The maritime climates of Madeira and the Azores are quite different from that of mainland Portugal. The southern slopes of Madeira are warm enough for tropical fruits if irrigation is provided. Some of the northern slopes are wet enough for temperate rain forests. The Azores are a little cooler but enjoy plenty of rain. 

Design of a garden and choice of plants 
Choosing plants for a Portuguese garden is not the same as choosing ones for cool wet climates. Consider varieties that originate or are already endemic in southwest Europe. They will tend to require less water and will survive under-watering or breakdown of the irrigation system. The use of endemic plants and shrubs also encourages local bird and insect life, under threat from urban growth. 

For houses in forest zones at risk of fire, there are fire resistant species, often succulents, that produce little leaf litter. Tall trees and shrubs should be well away from buildings and terraced areas around pools can provide refuges for animals. 

Lawns may look nice but can consume a lot of water. Groundcover can be more effective than lawns. Limit the amount of lawn to areas in which grass is needed, like a play area for children and select a suitable grass. Design the grass area to make watering easier. Long narrow areas and small odd shapes are hard to water efficiently. Avoid turf in the strip between the sidewalk and the road; most irrigation water will land on the paved surfaces and run off. 

Your local botanic garden and nursery personnel can help you identify suitable plants for your location. Most common garden plants can be found through commercial nurseries or garden centres. If you require a specific plant, many will be able to order for you. 

Irrigation
Limit plants with high water demands to small areas that can be watered efficiently. Grouping plants by water requirements is one way to guard against over-watering some plants and under-watering others. Use mulch to conserve soil moisture. Organic mulches help retain moisture so there is less need to water. 

While soils vary greatly in their ability to hold water, your garden and lawn should receive enough water to wet the soil to the bottom of the root zone each time you water. In the summer this could be more than 25mm per week (25 litres per square metre per week). Determine this by digging a hole 10- 15cm deep in the watered area the day after watering so the water has a chance to seep in. 

Avoid watering by hand, it often wastes water as there is excess runoff, and water does not penetrate the soil. This harms plants by forcing root growth too close to the surface. Properly used sprinkler systems can deliver a large quantity of water in a short time. They have the disadvantage of excessive evaporation, both during watering and from the plant and soil surface but may be the most effective means of watering lawns. The most efficient alternatives are trickle or drip irrigation systems and perforated hoses. With these soil moisture can be maintained at a level most suitable to plant uptake. If properly installed and maintained, little water is lost to evaporation or runoff and water use can be reduced by up to 50 percent. Any irrigation system requires regular maintenance, and even with filters and automated timers it needs regular checking. 

Employing a gardener 
You may consider employing a gardener or contract a gardening maintenance service. In either case ensure that you are insured against accidents on your property. 

Kitchen gardens, herbs and vegetables 
Many of the common household herbs originated from the Mediterranean areas and grow naturally in Portugal. Potted herbs are available in garden centres. The mild climate allows vegetables to grow through the winter, and the most difficult time for the kitchen garden tends to be during the heat of the summer. Some of the traditional Portuguese crops are sweet potatoes as well as ordinary potatoes, runner and broad beans, and field varieties of salad crops. In Madeira and some of the warmer parts of the Algarve the kitchen garden can provide a whole range of sub-tropical fruits and vegetables. 

Dealing with an established garden 
If you are lucky enough to inherit an existing garden give it a full year of growth to show what is there. Many of the natural flowers die right back during the summer and only reappear during the damp winter and spring. Mature natural trees are so slow growing that they are worth keeping as features. Some, such as the olive can be cut back and will produce new growth. 

Clubs and social events 
There are Botanic Gardens throughout Portugal which organise special events. Local environmental associations also organise visits and meetings on gardening and botanic subjects.