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Mediterranean gardening has many benefits
October 31, 2008
CORVALLIS, Ore. – You don't need to be Spanish, Italian or Greek to enjoy the beauty of Mediterranean gardening. Other parts of the world that also have mild, wet winters and hot, dry summers can take lessons from the many lovely gardens in this Old World region and its centuries, even millennia, of experience with these conditions. These gardens use plants that are able to store the moisture they need in the winter and survive – even thrive – through the summer without irrigation.
Although most of the Pacific Northwest doesn't normally have hot, dry summers, a few areas in rain shadows do. The Willamette Valley is one of these, and with generally mild, wet winters, it comes close to having a true Mediterranean climate. Eastern Oregon has cold winters, but its weather also follows the pattern of winter precipitation and dry summers. Even the coastal areas in Oregon, with mild, wet winters and relatively dry summers, have a similar pattern.
If you'd like to cut back – or even eliminate summer watering – Mediterranean gardening might be right for you, suggests horticulturist Linda McMahan of the Oregon State University Extension Service.
Mediterranean gardening is different from xeriscaping, although they are both waterwise approaches. Xeriscaping is best suited for desert climates with only a few inches of total precipitation for the year. By contrast, Mediterranean gardens require wet winters when plants can store up moisture to see them through the summer. What Mediterranean gardening and xeriscaping have in common is to reduce or eliminate artificial watering once plants are established.
Far from limiting your landscape choices, plants suitable for Mediterranean gardening – trees, shrubs, perennials and annuals, many of the common herbs and most of the spring and fall bulbs – have been developed not only near the Mediterranean Sea itself, but also in the other Mediterranean zones of the world. Horticulturists generally recognize four Mediterranean climate zones in addition to the one around the Mediterranean Sea: southern and southwestern Australia, central Chile, coastal California and the western cape of South Africa.
Since the closest of these to the Pacific Northwest is coastal California, it has contributed many plants that are already well known and widely used here in the Northwest. For instance, Ceanothus is a California native with species and varieties that grow well in the various parts of Oregon without summer watering once they're established. California fuchsia (Epilobium canum, also sold as Zauschneria californica) is another California native that grows well in Oregon both east and west of the Cascades.
In general, plants that have evolved in conditions similar to those in your garden tend to require less labor to keep them growing well. If they're well suited to their climate and specific site, it stands to reason they'll need less nurturing than exotic species.
A good place to start looking for plants that won't need coddling with irrigation in the summer, said McMahan, is among the native plants that have many characteristics of those from true Mediterranean regions.
"Especially widespread and appropriate are native shrubs like mock orange (Philadelphus lewisii) and some of the Ribes, like red flowering currant, (Ribes sanguinium) from western Oregon and higher elevations in eastern Oregon," said McMahan. "Golden currant (Ribes aureum) from eastern Oregon also grows well on both sides of the Cascades."
Building a Mediterranean garden requires more than just choosing the right plants. Such a garden needs to incorporate planning and gardening techniques designed to allow it to thrive through summer droughts. Trees should be placed where they will provide dappled shade in the hottest part of the day. Windbreaks can reduce evaporation from stressed plants. The generous use of mulch reduces evaporation and helps keep roots from overheating in the sun, preventing stress.
"Large rocks add protection and shade as well as places for water to condense," said McMahan. "Rock gardening designs can be used to elevate plants and improve drainage. Rocks are also useful as edging to outline raised beds."
Soils in the Mediterranean tend to be poor, sandy and rocky, so the native plants there are used to excellent drainage. While this means they don't need to be fed heavily, it also means that the clay soils common in much of the area can present a problem for some plants. There are some simple ways to provide good drainage in trouble spots. For instance, by designing irregular mounds into a garden using new, well draining soil – much like building raised beds without frames – a person can provide both good drainage and also visual interest.
"Using plants from similar climate zones means they're more likely to be in balance with their surroundings and less likely to become invasive," said McMahan. "Even so, plants of one Mediterranean zone can sometimes become invasive in others. Any time you introduce plants from another region into your garden, you need to aware of their invasive potential. For example, lemon balm (Melissa officinalis) which is native to the Mediterranean is considered invasive in Oregon."
English country gardens with their abundant foliage and gardens filled with lush semi-tropical plants, as gorgeous as they are, are not necessarily the best fit for every part of the world. With a slight change in your paradigm, said McMahan, a Mediterranean garden blooming among tiles and rocks in a cool shifting shade might bring you just as much pleasure. And save a lot on labor and your water bill.
Source: Linda McMahan