This column includes another visit to one of the world’s five Mediterranean climate regions, described more narrowly as southern and southwestern Australia, central Chile, coastal California, the Western Cape of South Africa and around the Mediterranean Basin.
These regions are characterized by wet, mild winters and hot, dry summers.
Each of these regions is small in area and together, they comprise a tiny percentage of the globe’s 107 million square kilometers of habitable land.
The Mediterranean climate regions include plants that have evolved in — and native to — this specific climate. The regions are relevant to gardeners who live in one of the regions because they can garden readily and easily with plants from the other regions.
In this column for gardeners in the Monterey Bay area, within one of the Mediterranean climate regions, we look at the plants of the four other regions.
In previous columns, we focused on the plants of the Mediterranean Basin and central Chile. Those columns have been archived and can be accessed respectively at tinyurl.com/mry87mv2 and tinyurl.com/2rw2sy46.
Today’s column presents a brief overview of the plants of Australia’s Mediterranean climate region, located on the southern and southwestern coast of the continent. The photo gallery features plants from this special part of Australia and now growing in my garden. These are selections from the UCSC Arboretum’s garden shop.
The region’s features
Australia is the world’s smallest continent and the sixth largest country by total area, with about 78% of the area of the United States. Australia is called the “island continent” and is considered by some to be the world’s largest island.
Australia has various landscapes, including tropical rainforests, mountain ranges and a large desert (the Outback) in the continent’s center.
The continent also includes various climate zones. The Köppen classification system has 15 different climate zones and Australia’s Bureau of Meteorology identifies 27 subzones.
The temperate zone, along the southernmost part of the continent, includes the Mediterranean region, with Perth on the region’s western end and Adelaide on the eastern end.
The native plants of Australia’s Mediterranean region have developed drought tolerance and methods of surviving fires and nutrient-poor soils.
Shrubs
• Kangaroo paw (Anigozanthos spp.), iconic plant with tubular, brightly colored flowers;
• Banksia spp., known for cone-shaped flowers and unique seed pods (This genus is named for naturalist Sir Joseph Banks, who collected the plant during explorer James Cook’s first voyage to the Pacific Ocean);
• Bottlebrush (Callistemon spp.), featuring cylindrical, brush-like flowers in red, pink or yellow;
• Grevilleas spp. has diverse sizes and forms, with intricate blossoms;
• Coastal rosemary (Westringia fruticosa), a gray-green shrub with lavender-to-white flowers; and
• Plants from Australia’s Mediterranean region grow readily in Monterey Bay area gardens and can bring a share of exotic horticulture.
Trees
• Grass Tree (Xanthorrhoea spp.), a feature of the Australian bushland with blackened trunk and long leaves;
• Albany blackbutt (Eucalyptus staeri), a medium-sized eucalyptus with fibrous bark and white flowers;
• Peppermint tree (Agonis flexuosa), a graceful tree with weeping foliage and small white flowers.
Groundcovers, perennials
• Blue lechenaultia (Lechenautia biloba), a small shrub with vivid blue flowers;
• Everlastings (Rodanthe spp. and Chrysocephalum spp.), daily-like flowers, with pink, white and yellow varieties;
• Kangaroo grass (Themeda triandra), ornamental seed heads.
Climbers
• Hardenbergia (Hardenbergia violacea), resembles a Wisteria with purple flowers;
• Kennedia (Kennedia prostrata), often grown as a groundcover with red pea flowers.
Sources of Australian plants
To observe a variety of Australian native plants, visit UC Santa Cruz’s Arboretum & Botanic Garden, which has devoted a large section to these plants. Of particular interest is the Australian Rock Garden, featuring smaller plants that could be included in a typical residential garden.
The Arboretum’s Norrie’s Gift & Garden Shop has a changing inventory of Australian plants. Visit shopucscarboretum.com to explore offerings to consider for your garden.
Other sources include Australian Native Plants, in Ventura County (australianplants.com), and Monterey Bay Nursery (montereybaynsy.com/Aust.html).
Most garden centers have at least a small section of Australian plants.
This week in the garden
You could focus on these tasks this week, although they are seasonal priorities.
Pruning and maintenance of trees and shrubs: Many trees and shrubs are entering dormancy, so now is a good time for light pruning to remove dead or diseased branches. Schedule heavy pruning for late winter, when these plants are ready for new growth. Rake and compost fallen leaves to prevent disease and enrich the soil.
Soil care and mulching: Apply a 2-to-4-inch layer of organic mulch around plants to retain moisture, regulate soil temperature and suppress weeds. Incorporate compost into garden beds to improve soil structure and fertility.
Enjoy Australian plants in your garden!
Tom Karwin is a past president of Friends of the UC Santa Cruz Arboretum and the Monterey Bay Iris Society, a past president and Lifetime Member of the Monterey Bay Area Cactus & Succulent Society and a Lifetime UC Master Gardener (Certified 1999-2009). He is now a board member of the Santa Cruz Hostel Society and active with the Pacific Horticultural Society. To view photos from his garden, facebook.com/ongardeningcom-566511763375123. For garden coaching info and an archive of On Gardening columns, visit ongardening.com for earlier columns or visit www.santacruzsentinel.com/ and search for “Karwin” for more recent columns. Email comments or questions to gardening@karwin.com.