California, like other Mediterranean climate zones, is situated on a southwest-facing coastline with high hills sheltering a lower lying coastal plain.
Another feature common to similar zones are the densely occupied urban areas – Los Angeles, San Francisco and San Diego. There are coastal ranges with less development, and these retain much of the original vegetation. The soils of California are mostly alkaline but there are exceptions with levels ranging from pH 5 (acidic) to 8.5 (alkaline).
Rainfall and humidity follow a north south divide – wettest in the north and drier in the south merging into the Mojave desert area of Mexico. The summer coastal fogs provide humidity which supports the famous redwood forests, similar to the sea fogs on the Atlantic west coast of the Algarve giving some support to native vegetation.
Fire is a constant and natural part of the life cycle for a vegetation which has adapted to periodic burning. Plants have developed strategies for regeneration such as shrubs sprouting from root crowns, seedlings of annuals and bulbs giving a spectacular spring display following the first winter rains. Again, this is similar to Algarve hill sides following summer fires.
Ceanothus thyrsiflorus – a mounding evergreen shrub with intense blue flower spikes. There are about 30 species of Ceanothus (California Lilac), including evergreen and deciduous shrubs and small trees. Small flowers in clusters are often scented and attract bees. Flowers are white, pink or several shades of blue, and come in late spring. These will grow in nitrogen poor soils and, once established, do not need irrigation.
Dudleya pulverulenta (Chalk Dudleya) for those who like succulents. This is found in rocky areas in coastal and inland mountains and desert foothills. It likes to be planted in rock formations at an angle so that water does not gather in the rosette. It produces a number of tall erect pinkish white stems, which support often thousands of pointy, rosy-red flowers. A much hardier plant for the garden environment than the more commonly available Dudleya brittoni.
Eschscholzia californica (California poppy) is tough, fast-growing, drought-tolerant, self-seeding, and easy to grow in gardens. It is best grown as an annual, in full sun, but it will tolerate part shade. It prefers well-drained sandy, often poor soils. The flowers range from yellow through to orange and give colour to early summer gardens. In mild climates it can be a perennial.
Fremontodendron californicum is a shrub with large bright yellow flowers and evergreen flannel like hairy foliage. It thrives on well drained sandy soils and summer watering will kill an established plant. In its native habitat the long roots reach out for moisture from nearby water sources, such as orchards or stream beds.
Iris bracteata, I. douglasiana, I. hartwegii and I.tenuissima are four of the 174 iris species native to California which are drought tolerant. They prefer partial shade, woodland edge sites.
Salvia ‘Allen Chickering’ is a hybrid selected for garden use from Salvia clevelandii. and Salvia leucophylla. ´Allan Chickering´ tolerates almost any soil type. There are 90 salvias native to California with numerous tough and drought tolerant hybrids to choose from.
Salvia apiana (White Sage) fragrant, with silver-white leaves, and clusters of white flowers with lavender streaks, food source for bees, butterflies, birds, and other wildlife. Adaptable to a variety of soil types. Soil PH: 6.0 – 8.0. Whilst native populations are threatened, it comes easily from seed and needs no irrigation. There is also a selected compact form for garden use.
These are just some of the iconic plants of California that can be grown here, and their drought resistance is only one of the attractive qualities they bring to Algarve gardens. The California native plant database lists 506 plants with very low water needs.
California Native Plant Society database https://calscape.org/
Rosie Peddle [email protected]