Pacific Coast gardeners, especially those in California, are familiar with New Zealand flax (Phormium tenax), cow-itch tree (Lagunaria patersonii), Norfolk Island pine (Araucaria heterophylla), hopseed bush (Dodonea viscosa), kentia palm (Howea forsteriana), shaving brush palm (Rhopalostylis baueri), and westringia (Westringia fruticosa). Yet few realize that these and a host of other plants—all suitable for cultivation in favored locales—originate on two littleknown Australian islands isolated in the South Pacific.
Norfolk and Lord Howe, about 950 and 450 miles, respectively, east of Australia at about 30° S latitude in the Tasman Sea, are the heavily eroded remnants of extinct volcanoes. They lie on parallel submarine ridges that, in ancient times, may have connected these islands with New Zealand and New Caledonia. Surrounded by cool, clear, blue green water dotted with coral reefs, both islands have a mild, moist, subtropical climate not too dissimilar from that of coastal California except that they experience neither frost nor hot, dry summers.
Because of their climate and isolated location, both islands have intriguing floras more in common with those of New Zealand and New Caledonia than Australia. While visiting in October, 2005, we were struck by the thought that many of the plants growing there would probably grow well in West Coast gardens.
Although tourism on each island is tightly controlled (camping is not allowed and visitors must show proof of lodging upon arrival), both make marvelous destinations for those interested in plants, animals, and other aspects of island natural history, plus hiking, snorkeling, star-gazing, and simply relaxing in a near tropical paradise without either oppressive humidity or extreme heat. There are no poisonous land animals, food and lodging range from adequate to excellent, and residents are friendly and accommodating. Both islands are unusually clean, lack billboards, graffiti, and auto traffic, and islanders are extremely respectful of their island environments and fragile ecosystems. There is regularly scheduled air service from Australia and New Zealand to Norfolk, and from Australia to Lord Howe.
The larger of the two islands (about fourteen square miles and rounded in shape), Norfolk rises out of the sea on sheer cliffs, except on the southern coast where the land gently slopes into the small, coral-ringed Emily Bay. The highest point, Mt Pitt, rises to roughly 1,000 feet elevation. Rainfall averages about fifty inches annually, and temperatures range from 40° to 80° F. There are 171 species of plants indigenous to the island of which forty-seven are endemic (found nowhere else). From any vantage point or vista, the island’s namesake, the widely popular Norfolk Island pine (Araucaria heterophylla), dominates the skyline.
Home to 1,700 year-round residents, Norfolk was first settled in 1788 with the establishment of a penal colony from Australia. During the early 1800s, human activity and introduced animals destroyed nearly eighty percent of the island’s native forest. Indeed, several of Norfolk’s endemic species are highly endangered, including the Philip Island hibiscus (Hibiscus insularis) and abutilon (Abutilon julianae); both are now only known from Philip Island, an islet about three miles off the south shore, but are thought once to have been found on the main island as well.
The handsome Philip Island hibiscus has flowers with pale to creamy yellow corollas and purplish throats. By 1963, there were only eight surviving plants. Although now more widely cultivated on the island and reintroduced back into the wild, its propagation has proven difficult, and plants take ten to twelve years to reach maturity.
The equally handsome Philip Island abutilon was long thought to be extinct until a biologist, rappelling down a cliff in 1985, saw a clump of an unfamiliar, yellow-flowered shrub. Later identified as the “extinct” Abutilon julianae, it is now being propagated and reintroduced back into the wild.
Despite the early devastation, some extensive stands of excellent native forest remain, primarily on Mt Pitt and Mt Bates, encompassed within the island’s national park. Easily accessible by car and laced with numerous hiking trails, forested areas in the national park yield a wide variety of interesting plants. Margaret Christian, Norfolk Island’s resident naturalist, accompanied us for a day and pointed out some of the island’s most noteworthy plants.
Unusual or rare tree species, in various mopsptly tropical families, forming the forest canopy include Ungeria floribunda (Sterculia-ceae), Sarcomelicope simplicifolia (Rutaceae), Elaeodendron curtipundulum (Celastraceae), and Baloghia inophylla (Euphorbiaceae). None, it seems, have gained a foothold in the world of horticulture. In moist areas, the most conspicuous trees are two large tree ferns (also found in southeastern Australia: Cyathea australis, about thirty-five feet tall, and C. brownii, more than seventy feet tall, one of the tallest in the world. Shaving brush palms (Rhopalostylis baueri) are gregarious, dominating the forest understory with seedlings and saplings, while adults poke their crowns through the canopy. Meryta latifolia, with large, simple, tropical-looking leaves, is conspicuous and showy.
Asplenium dimorphum, Doodia media, Phymatosorus pustulatus, and Arthropteris tenella are but a few of the ferns common in the shady, moist understory. Another, the rare primitive fern, Marattia salicina, has a large, bulbous rhizome and fronds to over fifteen feet long. The island is also home to nine species of orchids, including a Dendrobium that forms clumps up to two feet across.
In more open areas along forest margins, hopseed bush, with colorful fruits ranging from white to light red to a deep, deep red—our favorite—was particularly striking and much more ornamental than the forms commonly cultivated in California. New Zealand flax was in bloom with tall spires holding flowers and fruits well above the foliage. Some clumps were nearly eight feet tall! Dianella intermedia, a small but attractive liliaceous herb with sword-shaped leaves to two feet tall and showy blue to purple fruits, is uncommon, as is the handsome but endangered Euphorbia norfolkiana. A member of the agave family that we adored was Cordyline obtecta; its fresh, green, strap-like leaves and clusters of showy white flowers always drew our attention.
Lord Howe Island
Home to the world’s southernmost coral reef, Lord Howe Island is a UNESCO World Heritage Site. Roughly seven miles long and from 0.3 to 1.8 miles wide, this crescent-shaped island is about half the size of Norfolk but different in its topography and history. Dominating the southern end of Lord Howe are the twin precipitous peaks, Mt Gower and Mt Lidgbird; at 2,870 and 2,498 feet, respectively, they are the highest points on the island. The tops of both peaks, typically shrouded in clouds and mist, harbor a unique cloud forest. In contrast, the middle and northern parts of the island have low, gently rounded hills, covered in some areas by wind-sculpted vegetation. The climate is similar to that on Norfolk, but rainfall is a little more generous, averaging about sixty-five inches annually. There are 241 species of plants indigenous to Lord Howe, of which 105 are endemic.
Home to only three hundred year-round residents, Lord Howe was discovered in 1788, yet remained uninhabited until 1834, when fewer than ten settlers established a tiny outpost to replenish supplies of passing ships. The population grew slowly, reaching only thirty-five by 1870. In contrast to Norfolk, human activity has had much less impact on Lord Howe, with about eighty-five percent of the island still covered in native forest.
Much of the lowland forest is dominated by Howea forsteriana, commonly referred to as the kentia palm, a plant that boomed in popularity in Victorian times as a hothouse and indoor potted specimen. Due to a surging demand for these palms in Europe and North America, seeds were taken to Norfolk Island in 1828 to establish a kentia palm seed business there. Today, both islands’ economies still partially depend upon exporting kentia palm seeds (Norfolk) and sprouted seeds (Lord Howe) to nearly all parts of the world.
Lord Howe is sufficiently small that one can easily get around on a rented bicycle, and numerous hiking/walking trails lace the island. In addition to kentia palms, other conspicuous lowland native plants include the trees Cryptocarya triplinervis (Lauraceae) and Drypetes deplanchei subsp. affinis (Euphorbiaceae), sentry palm (Howea belmoreana), cow-itch tree, the stilt-rooted Pandanus forsteri, and Pittosporum erioloma. Giving the impression of a vast, expansive outdoor cathedral, Ficus macrophylla subsp. columnaris is especially conspicuous and dramatic with numerous trunks, aerial roots, and spreading branches that can cover up to an acre or more.
Common lowland herbaceous plants include an iris relative (Dietes robinsoniana), an orchid (Dendrobium macropus subsp. howeanum), and numerous ferns including Adiantum hispidulum, Asplenium milnei, Doodia media, Phymatosorus pustulatus subsp. howensis, and staghorn fern (Platycerium bifurcatum), the latter forming large, conspicuous clumps on tree trunks and rocks.
Unlike Norfolk, upland or montane forest on Lord Howe differs dramatically from that of the lowlands. The best place to see montane forest is to make the extremely arduous trek to the summit of Mt Gower. On our first night on the island, we attended a lecture by Ian Hutton, author and resident island naturalist, who gave us an overview of Lord Howe’s natural history. Although Ian’s talk emphasized the difficulty of ascending Mt Gower, we learned the next day, after making the climb ourselves, that words are insufficient to describe the ascent. The nine-mile round-trip trek requires a guide, the wearing of a protective helmet in some stretches, and the use of ropes in many instances to pull oneself up vertical cliffs; only those in excellent physical condition and unafraid of heights should consider this trek.
However, an unusually rewarding experience awaits those fortunate and sufficiently fit to make the ascent. Below the summit, the forest is filled with Cryptocarya gregsonii, Dysoxylum pachyllum (Meliaceae), Melaleuca howeana, and Metrosideros nervulosa, along with another palm (Hedyscepe canterburyana), while ferns, orchids, and other herbaceous plants, like westringia, compose the understory. Geniostoma petiolosum is a privet-like shrub, conspicuous by its strongly odoriferous flowers that attract pollinating flies.
Upon arriving at the summit plateau, one enters a fantasy “never-never land” of plant life, one that even the best Disney imagineers could not duplicate. Nearly every square inch of branch or trunk surface in this dense, shrubby, cloud forest is clothed with mosses, lichens, ferns, and other epiphytic plants. Dominating this scrubby forest are small trees and shrubs of Dracophyllum fitzgeraldii and Zygogynum howeanum and another palm (Lepidorrhachis mooreana), notable for its showy clusters of reddish purple fruits. Several species of Blechnum ferns are conspicuous in the understory, and a carpet of thick, spongy moss covers the ground. The ever-present mist and fog hanging or swirling among the plants made for an unforgettable experience.
A Pacific Horticulture Tour An Island Excursion: Norfolk, Lord Howe, and More
With counsel from Kerry and Don, we are reorganizing our proposed tour to these exotic South Pacific islands, and tentatively rescheduling it for November, 2008. If you would like to receive a brochure when it is ready, please send an email to firstname.lastname@example.org or phone 510/849- 1627.