Hawai'i tropical high shrublands
Hawai'i tropical high shrublands
The Hawaiʻi tropical high shrublands occupy the upper slopes of four great volcanoes in the US state of Hawaii: Mauna Kea, Mauna Loa, and Hualālai on Hawaiʻi Island, and Haleakalā on Maui. Above the forest line, alpine deserts and grasslands give way downslope to subalpine shrublands, where hardy, cold- and drought-adapted plants dominate, including ʻāheahea (Chenopodium oahuense), ʻōhelo ʻai (Vaccinium reticulatum), naʻenaʻe and related Dubautia shrubs, and ʻiliahi sandalwood (Santalum haleakalae), alongside tussock grasses such as Deschampsia nubigena. This is a high-elevation subtropical highland climate marked by dry, cold conditions on the exposed summits. Its signature plant is the Hawaiian silversword, ʻāhinahina (Argyroxiphium sandwicense), part of an endemic alliance descended from a North American tarweed, while the nēnē goose and ʻuaʻu (Hawaiian petrel) are among its native fauna. The ecoregion is considered vulnerable, pressured by grazing and trampling from feral livestock and by invasive species. For mountain or rock gardeners, the native ʻōhelo (Vaccinium reticulatum), a low cranberry relative, is a notable cold-hardy ornamental from this flora.
RESOLVE 639
Oceania
715 sq mi
Tropical & Subtropical Grasslands, Savannas & Shrublands
Landscape type
Tropical & Subtropical Grasslands, Savannas & Shrublands
Plant region
Oceania
Region footprint
715 sq mi
Habitat pressure
Nature Could Recover (Dinerstein NNH 3)
Source & care
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Use this as the broad planting pattern for the region: Warm grasslands and savannas where grasses dominate and trees are scattered, maintained by seasonal rainfall, grazing, and fire. They support large herbivore communities and respond sharply to wet–dry cycles. For garden decisions, pair that context with the plant list below, then narrow by your site's light, water, soil, and mature-size constraints.
Range & origins
Marker placed inside the RESOLVE 2017 polygon at 19.5°N, 155.6°W.
Region through time
Modern footprint
RESOLVE 2017 maps 715 sq mi
This boundary is a modern ecological footprint for Hawai'i tropical high shrublands, not a permanent line on the planet. It is useful for today's plant and wildlife context because it follows recurring vegetation, climate, landform, and disturbance patterns.
Why here
tropical & subtropical grasslands, savannas & shrublands conditions
The region sits in the Oceania realm and is classed as tropical & subtropical grasslands, savannas & shrublands. Elevation, moisture, fire, soils, coasts, and human land use can all make the real landscape more varied than a single map color suggests.
Change pressure
Nature Could Recover
Plotwright shows this as the current RESOLVE footprint. Over decades to centuries, warming, disturbance, invasive species, land use, and restoration can move the living edge of a region even when the reference map stays fixed.
Similar planting regions
Browse other regions with a similar hot, dry-summer rhythm. Their plant lists can suggest species and combinations worth comparing.
RESOLVE 640 - Oceania
Hawai'i tropical low shrublands
The Hawai'i tropical low shrublands occupy the dry, leeward lowlands of the main Hawaiian Islands, blanketing the lowest slopes of the larger islands and nearly all of the smaller ones such as Lāna'i, Kaho'olawe, and Ni'ihau (the Northwestern Hawaiian Islands form a separate ecoregion). The vegetation is a mix of native grasslands and coastal shrublands carpeted in low-growing plants, dominated by 'ilima (Sida fallax), 'a'ali'i (Dodonaea viscosa), naupaka (Scaevola), pūkiawe (Styphelia tameiameiae), and the grass kāwelu (Eragrostis variabilis). This is the driest of all lowland habitats in the archipelago, with rainfall concentrated in the winter months, giving it a tropical-savanna character. More than 90 percent of its plant species are found nowhere else, including the flagship 'ōhai (Sesbania tomentosa), and the small flowers are pollinated by native Hawaiian yellow-faced bees; today the ecoregion is rated critically endangered, with little intact habitat left after losses to development, fire, feral animals, and invasive species. For drought-tolerant native plantings, the shrubland's own 'ilima, naupaka, and 'a'ali'i are well-suited ornamental choices.
Tropical & Subtropical Grasslands, Savannas & Shrublands
Zones 13b
+2.9°F by 2070
587 sq mi
NNH tier 4
RESOLVE 641 - Oceania
Northwest Hawai'i scrub
The Northwest Hawai'i scrub ecoregion spans the remote Northwestern Hawaiian Islands, a chain of low atolls and islets in the Oceanian realm stretching roughly 1,350 to 1,600 kilometers from rocky Nihoa in the southeast to low Kure Atoll, all within the U.S. state of Hawaii. Set on the eroded remnants of ancient volcanic islands and coral sand, the vegetation is treeless tropical shrubland: banks of low, salt-tolerant shrubs and ground plants fringing lagoons, with common species including Portulaca lutea and Boerhavia repens. Conditions are harsh, with storms, flash floods, and tsunamis shaping this tropical island habitat. The ecoregion harbors several endangered endemic plants, among them the Nīhoa fan palm (Pritchardia remota), Schiedea verticillata, and Amaranthus brownii, alongside the endangered Hawaiian monk seal and endemic birds such as the Laysan duck, Laysan finch, and Nīhoa finch; collectively the islands form the largest tropical seabird rookery in the world and lie entirely within the protected Papahānaumokuākea Marine National Monument. For gardeners, the native fan palm genus Pritchardia represents the region's most horticulturally notable group, the same palms that once formed forests on Nihoa.
Tropical & Subtropical Grasslands, Savannas & Shrublands
Zones 13b
+2.6°F by 2070
6 sq mi
NNH tier 4
RESOLVE 34 - Afrotropic
Angolan mopane woodlands
The Angolan mopane woodlands stretch across southwestern Angola and northern Namibia, running along the Owambo Basin and surrounding the salt flats of the Etosha Pan. As the name suggests, the ecoregion is dominated by the mopane tree (Colophospermum mopane), which grows as a single-stemmed tree up to about 10 meters tall or, where conditions are harsher, as a dense shrub, alongside associated Acacia, Combretum, and Commiphora species. The climate is dry, with rainfall concentrated in the summer and peaking in late summer. The woodlands shelter elephants, black and white rhinoceros, lion, and cheetah, as well as the near-endemic black-faced impala, and the wider region is anchored by protected areas including Namibia's Etosha National Park. Mopane here also has a direct human use, as the caterpillars of the mopane emperor moth are gathered locally as food.
Tropical & Subtropical Grasslands, Savannas & Shrublands
Zones 11a-12b
+4.2°F by 2070
74,248 sq mi
NNH tier 2
RESOLVE 35 - Afrotropic
Angolan scarp savanna and woodlands
The Angolan scarp savanna and woodlands form a long, narrow strip along the coast of Angola, running from the Atlantic shore up the steep west-facing escarpment that climbs roughly 1,000 meters to the country's central plateau. Vegetation shifts dramatically with elevation, grading from dry woodland and wooded grassland—where baobab, Strychnos, and Acacia welwitschii grow—up to humid mist and cloud forests whose canopy includes Khaya anthotheca, Bombax buonopozense, and Spathodea campanulata. The climate is tropical with summer rains; the coastal belt, cooled by the Benguela Current, stays humid but receives relatively little rain, while the escarpment is far wetter. Despite being poorly studied and only partly protected within reserves such as Quiçãma National Park, the region is rich in endemics, including the red-crested turaco and the grey-striped francolin, and is classified as Vulnerable. For gardeners, the showy African tulip tree (Spathodea campanulata), grown as an ornamental in warm climates worldwide, is native to these escarpment forests.
Tropical & Subtropical Grasslands, Savannas & Shrublands
Zones 12a-13b
+3.7°F by 2070
52,811 sq mi
NNH tier 4
RESOLVE 36 - Afrotropic
Angolan wet miombo woodlands
The Angolan wet miombo woodlands blanket most of the central Angolan plateau and extend north into the Democratic Republic of the Congo, sitting largely at elevations between about 1,000 and 1,500 meters. The defining habitat is miombo woodland, a moist deciduous broadleaf savanna dominated by legume trees of the family Fabaceae (subfamily Caesalpinioideae), especially the genera Brachystegia, Julbernardia, and Isoberlinia, with grassland and sandy-soil openings between the stands. The climate is tropical and notably wetter than the surrounding savanna, with rainfall strongly concentrated in the hot summer months from roughly November to March. The ecoregion is the stronghold of the giant sable antelope (Hippotragus niger variani), a critically endangered Angolan endemic protected at Cangandala National Park, and it also harbors a strict-endemic rodent, Vernay's climbing mouse. For gardeners, the signature native flora here are the canopy-forming Brachystegia and Isoberlinia legume trees that give the miombo its character.
Tropical & Subtropical Grasslands, Savannas & Shrublands
Zones 12a-13b
+4.0°F by 2070
173,318 sq mi
NNH tier 4
RESOLVE 181 - Australasia
Arnhem Land tropical savanna
The Arnhem Land tropical savanna covers the rugged Arnhem Land peninsula and its offshore islands, including the Tiwi Islands, Groote Eylandt, and the Wessel Islands, in Australia's Northern Territory. Eucalypt open forests dominate the landscape, led by Darwin stringybark (Eucalyptus tetrodonta) and Darwin woollybutt (Eucalyptus miniata) over a tall understory of Sorghum grasses, interspersed with monsoon rainforest patches, mangroves, and Melaleuca swamp forests. The climate is tropical and strongly monsoonal, with a summer wet season and a largely rainless dry season. Long isolation has made it exceptionally diverse: over 1,900 plant taxa have been recorded, at least 200 of them found nowhere else, and a 2017 assessment found that 36% of the ecoregion lies within protected areas such as Kakadu National Park.
Tropical & Subtropical Grasslands, Savannas & Shrublands
Zones 13a-13b
+4.0°F by 2070
61,266 sq mi
NNH tier 2
Sources & citations
Cite this page
For lesson plans, articles, or regional planting notes that use this Plotwright page. To cite the underlying ecoregion framework or a specific editorial profile, use the source cards below.
Plotwright. (n.d.). Hawai'i tropical high shrublands (Hawai'i tropical high shrublands). Retrieved 2026, June 14, from https://plotwright.garden/regions/resolve-639
Sources for this region
This page cites Plotwright first for the compiled view, then lists the upstream framework, climate, and editorial source pages so readers can cite the original material directly.
RESOLVE 2017 Terrestrial Ecoregions (Dinerstein et al.)
Primary ecoregion framework
Backs 4 fields
RESOLVE id
Biome + realm
Area
NNH tier
USDA Plant Hardiness Zone Map
Published hardiness-zone authority
Backs 1 field
USDA zone range