Gardening in coastal areas presents special challenges. Soil types may vary from one location to the next, but all coastal gardens share the vagaries of climate and microclimates. Depending on the area, temperatures may be hot during the day and cold at night. Winds may be mild gusts or stormy gales, and salt spray is omnipresent. The best plants for coastal gardens are those that are specifically adapted to these rigorous conditions.
Aucuba japonica, or Japanese laurel, adapts well to a wide variety of gardening environments. It grows in shade and is unaffected by pollution, dry soil or the usual coastal conditions of wind and salt spray. Evergreen aucuba has showy green leaves splashed with speckles or streaks of yellow or gold. At maturity, it reaches a height and width of 6 to 10 feet. Spring brings small, reddish-purple flowers. Female plants produce red berries in the fall. Aucuba will thrive in almost any soil type that is not waterlogged. It grows well in USDA Zones 6 through 10 and is useful in coastal gardens as a border, hedge or specimen plant.
Natal plum, Carissa macrocarpa, is an attractive choice for coastal gardens. Dense and closely branched, it is useful as a sprawling shrub or hedge. If you prune it into tree form, the natal plum can reach a height of 20 feet at maturity. Leathery, dark green leaves grow 1 to 3 inches in length. Forked spines line the branches and twig ends and make natal plum an almost impenetrable barrier when used as a hedge. White flowers are about 2 inches across and are pleasantly fragrant. Red, plum-shaped berries are 2 inches long and edible. Natal plum prefers sandy, well-drained soil and does best in full sun. It is drought tolerant and performs well in USDA Zones 9 to 11.
Pittosporum tobira is a tough, durable evergreen that is tolerant of salt spray, drought and heat, which makes it well suited to coastal gardens. It has a slow-to-moderate growth rate, and you can it prune severely to maintain the size you prefer. Pittosporum grows in sun or shade and requires well-drained soil. At maturity, size ranges from 8 to 12 feet in height and 4 to 8 feet in width. Pittosporum's form is dense and mounding. Creamy-white flowers in 2 to 3-inch clusters appear in late spring. Lustrous, dark green leaves grow 1 ½ to 4 inches in length. A popular variegated form has gray-green leaves with creamy-white margins that contrast well with other plants. Pittosporum is hardy in USDA Zones 7 to 10.