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Norman Bezona Prof emeritus University of Hawaii College of Tropical Agriculture

Norman Bezona
Prof emeritus
University of Hawaii
College of Tropical Agriculture

(Originally published May 2015) We will be taking the next several weeks off island and travel to Italy and visit some of the places where my family originated. Of course, we will check out the many beautiful gardens of northern Italy.

Even though the winter climate can be quite chilly by Hawaiian standards, many gardens appear to be almost tropical around Milan and Genoa where we will visit. These are examples of how we can create moods by the kinds of plants, architecture and nonplant elements we use in our gardens.

Cactus and succulents plus lots of bright colors make a garden feel hot and desert-like. Using pines, cypress and other high mountain or cool climate plants give the garden a Pacific Northwest, Japanese or European look.

Here in Hawaii, East meets West, so we have tremendous latitude in garden design. Bali exemplifies the use of plants, sculpture, architecture and water elements to achieve harmony with home and garden. Two books, “Tropical Asian Style” and “Balinese Gardens,” give some great visual tips on this style.

La Mortella, an island off central Italy

La Mortella, an island off central Italy

Italy is a great example of how a semi-tropical look can be achieved in a climate that is chilly much of the winter. The natural vegetation of the region is much like Austria, Switzerland or France, but with the use of palms, gardens have a whole different ambiance.

The air of freedom and informality in Hawaiian gardens is partly because of the exotic plant materials used. It is also because of the “hang-loose” tropical style of design found throughout the Islands. This consists of mixing many bold and colorful shrubs, ground covers and trees in a relaxed, unregimented manner.

Very tropical looking lanscape of Lake Garda in extreme No. Italy

Very tropical looking lanscape of Lake Garda in extreme No. Italy making good use of the cold hardy Trachycarpus palm.

The large variety of plants used in any particular garden has led to the local label of “chop suey” landscaping. Our type of garden design often grows out of the Hawaiian love for plants. This is “the more, the bettah” philosophy. It also develops from the giving nature of local folks. A plant always is an appropriate gift for any occasion. Before long, the garden and home are bursting with luxuriant vegetation. This type of landscaping gives a sort of well-maintained jungle effect. Examples of this can be seen along the Italian Riviera, Switzerland’s Lake Geneva and Italy’s lakes Como and Maggiore.

Surprisingly, the tropical jungle look often is more easily maintained than vast open expanses of lawn. Abundant vegetation also supplies more oxygen and reduces noise and visual pollution.

Many visitors to the Hawaiian Islands wish they could take a bit of the tropics home with them. This actually is possible since the hang-loose tropical look can be achieved almost anywhere. To develop that tropical look in cooler climates, however, the selection of materials should be those with a bold and colorful tropical presence.

Here are some tips for your mainland friends who want a touch of Hawaii at home.

Albizia

An example of the tropical looking, yet cold hardy, Albizia julibrissin

• Trees such as Albizia julibrissin, or Persian silk tree, are very tropical in appearance, with its Poinciana-like foliage and pink pompon flowers, this tree will tolerate conditions almost to zero degrees. The silk tree is native to Asia and can reach heights of up to 30 feet, but usually is much smaller, spreading like an umbrella to 20 feet. The tree’s filtered shade allows grass and other plants to grow underneath. It also makes a very good patio tree. It is a close relative to the giant Albizias falcataria of Puna, but is much smaller and well-mannered.

 • Of course, a tropical-looking garden must have palms, ferns and even bananas. Two species of hardy banana,Musa basjoo and Musa sikkimensis, can be grown in cool climates such as Seattle and even Germany. If you live in an area where temperatures seldom reach 10 degrees or colder, the Trachycarpus fortunei,or windmill palm, is a great one for the ultratropical look. It is relatively fast growing to about 30 feet. This palm should be used in groups of three to seven for a dramatic effect. The many healthy specimens in Seattle and Northern Italy attest to this tree’s ability to withstand cold. Another palm grown in cool Mediterranean gardens is the European fan palm,Chamaerops humilis. There are several other palms and palm-like trees that will grow as far north as Washington and even Switzerland. Plants from New Zealand, such as Cordyline australis, tree ferns and New Zealand flax are examples.
A tropical like setting in Portugal with the use of tree ferns.

A tropical like setting in Portugal with the use of tree ferns.

• Many tropical-looking plants thrive in the summer but freeze to the ground in winter. Hostas, cannnas and callas are examples. Some gingers, such as the guava jelly ginger, Hedychium greenei, from the Himalayas, can be grown as far north as Victoria, Britich Columbia, Canada. The last time we were in Europe, I saw hardy bananas growing in Switzerland. These bananas are root hardy and regrow every year even after freezing to the ground. Even taro can be wintered over with mulching along the West Coast of the U.S. and as far north as Washington, D.C.

• There are several hardy bamboos that will take temperatures as low as zero. One of my favorites isPhyllostachys vivax from China that will reach 70 feet tall. This is a running species and must be given plenty of room. Many Phyllostachys species are hardy even as far north as protected spots in Canada. For smaller gardens, there are many hardy well-mannered clumping species from which to choose. Close relatives of bamboo such as the Arundo donax, or Spanish cane, from the Mediterranean can be used in areas where temperatures are below zero. Although this giant reed can freeze down in winter, give it a protective mulch with a good rich soil and it will grow from 6 to 15 feet in a summer. Another popular bamboo relative is Pampas grass, or Cortaderia sellowana, from Brazil and Argentina. This versatile clumping grass will tolerate dry to wet soils and temperatures close to zero if protected by mulching.

The list of tropical look-alikes goes on. You might consider trees such as the hardy Eucalyptus species. These include the cider gum and snow gum that survive temperatures close to zero. Fruits such as the fig, pomegranate, olive and loquat can all be found growing as far north as Seattle and Vancouver.

Courtesy of VOLTAIRE MOISE Hardy banana, Musa sikkimensis and Trachycarpus palm growing in Seattle.

Courtesy of VOLTAIRE MOISE Hardy banana, Musa sikkimensis and Trachycarpus palm growing in Seattle.

Your mainland friends can experiment with these and others that nurseries and garden centers carry in their area or try some from more southerly locations. To avoid discouragement, check with garden books that cover plant hardiness. Sunset’s “Western Garden Book” also might give you some great ideas.

Remember, hardiness fluctuates. You can increase hardiness by plant conditioning and protection. For plants that are marginal, place them where they will get full advantage of the warmer microclimate in the garden. Temperatures often are warmer on the south sides of buildings, sheltered from cold winds. This applies to gardening in temperate Hawaiian gardens such as those in Volcano, upper Kaloko mauka in Kona and upper Saddle Road spots such as Pohakuloa.

With the world’s climate appearing to become warmer, who knows, you might find citrus trees in Washington one of these days.

Where possible, mulch tender tuberous plants such as cannas and calla lilies. This protects the soil from freezing. Trees such as the windmill palm can be wrapped with burlap or other protective material during extremely cold weather.

Folks on the mainland can use imagination and have a luxuriant tropical-looking garden. Experimentation with new plants will make them the talk of the neighborhood. And don’t forget the many potted tropical plants that can summer in the garden and be moved indoors to give a warm Hawaiian feeling on those dark winter days.

This information is supplied by the University of Hawaii College of Tropical Agriculture and Human Resources. For further information, contact the office near you.