GARDENING : The Coast Is Clear for Growers

Tending plants along the coast is unlike gardening anywhere else, say people who toil in the seaside soil.

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Chosing plants that don’t mind the salt air and constant wind and that prefer mild temperatures and high humidity is the key to success, they say.

The mild coastal weather creates a subtropical environment on Orange County shores where many sensitive plants thrive year-round. Bananas, bougainvillea, ferns, hibiscus and impatiens grow well along the coast, as do fuchsias.

The dominant influence on the climate--and thus growing conditions--along the coast is the ocean. Where “coastal” ends and “inland” begins is the point at which other geographic influences, such as the desert, also help shape the climate.

Horticulturists divide the coastal area into three zones, says certified nurseryman Steve Kawaratani, general manager of Laguna Nursery in Laguna Beach.

Seacoast 1 is the area right on the ocean. Plants located here must tolerate extreme conditions, including salt in the soil and salt spray.

Seacoast 2 is the area adjacent to Seacoast 1, which is protected by natural barriers such as other plants or boulders, or artificial barriers such as a wall or house. In this zone plants must tolerate some salt, but they aren’t actually sprayed by salt water.

Seacoast 3 is the area even further back. While still greatly influenced by salt air, the soil generally has no salt. In this area plants must be used that tolerate some salinity.

The width of each zone varies along with the terrain, so it’s up to individual gardeners to determine where their garden falls.

“In many ways we’re luckier to be gardening on the coast,” says Kawaratani. “We can safely do planting in the summer along the coast that you wouldn’t dream of doing inland at this time of year. Our weather is mild enough to install new lawns now. Inland during the summer you would have to water a new lawn constantly to keep it from burning up.”

It’s also much more comfortable to work in a coastal garden during the summer. Where the inland gardener is restricted to early-morning and evening gardening, the seacoast gardener can comfortably garden during most of the day.

Despite its benefits, coastal gardening does present challenges.

Perhaps the most disappointing limitation of gardening near the ocean is the inability to grow certain plants that need high heat.

Some flowering plants have trouble surviving on the cooler coast. Roses tend to mildew and rust when there isn’t a lot of sun, as do zinnias, hollyhocks, crape myrtle trees, petunias and vinca.

“Many tomato and pepper varieties that require hot summer temperatures don’t do well along the coast,” says Kawaratani. “If these vegetables do set fruit, it’s not likely to grow very big or ripen. To grow tomatoes, you must choose smaller types that were bred for coastal conditions, such as Early Girl.”

Some fruit trees, such as grapefruit, refuse to grow without the necessary heat, and many, such as oranges and grapes, may form fruit, but will not sweeten without intense heat and sunlight.

Cantaloupe and other melons also don’t grow well, if at all, without high heat.

Some fruit trees won’t thrive because of the lack of winter chilling along the coast. Peach and apple trees need winter temperature dips to produce fruit in the spring and summer.

There are a few varieties bred for coastal growing, however. Bonita and Babcock peaches and Gordon and Beverly Hills apple varieties do well on the coast.

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Gardening rules, however, were made to be broken. Just ask Laguna Beach gardener Robert Andri, whose garden sits on a bluff overlooking the ocean.

“Although I try to choose plants that do well on the coast, if I see something I want that is beautiful and isn’t for the coast, I will try it anyway, and everything I’ve tried has grown,” said Andri, who does his own landscaping.

“They told me that Japanese black pines [Pinus thunbergia ] and plumeria wouldn’t grow on the coast, but I’ve got them growing in my garden,” he says. “They also said that bougainvillea would get torn up by the wind, but it’s doing fine.”

By using PVC pipe and creating dams, Andri has fashioned waterways in his bluff, which is made up primarily of sandstone. To install his 18-foot black pines, he drilled holes in the sandstone and inserted the trees, which are thriving in very little soil.

To deal with the damaging salt air common at the seashore, Andri rinses off his plants by hand every other day to remove salt buildup.

There are plants that can take salty air, including carissa, myoporum, ice plants, yucca, manzanita, Monterey cypress and the aptly named saltbush. Many of these are desert plants that have a high resistance to alkalinity and salinity.

When you aren’t sure what will grow in a questionable area, Kawaratani suggests planting a saltbush or myoporum. “If they won’t grow in that location, then it’s too salty for anything to grow,” he says.

Plants that can do well on the coast often have small or waxy leaves that prevent damage from wind and salt air. They are also able to reduce the rate at which they lose water.

Even plants accustomed to the ocean wind don’t do well when the Santa Anas start blowing, says Wade Roberts, garden director of Sherman Library and Gardens in Corona del Mar.

These drying winds can kill seaside plants that are accustomed to moist conditions. “Two days of zero humidity and damaging winds can destroy the garden,” he says.

To combat the Santa Anas, Roberts suggests taking hanging baskets down and putting them in a protected area.

It’s also important to provide humidity to the garden, which can be accomplished by using a fogging nozzle found at the nursery.

Another challenge is that pests and diseases tend to multiply faster in the coastal climate. “When the weather becomes overcast and the humidity is high, it’s like a hothouse here,” says Kawaratani. “Snails, slugs and insects thrive in moist conditions. This weather is also an incubator for various lawn diseases and foliage problems.”

To combat the increase in pests and diseases, be a vigilant gardener and frequently inspect plants. Remove weak or damaged branches, and leaves and spent flowers, where insects may hide.