This remote ecoregion covers the Tristan da Cunha archipelago, including Tristan, Nightingale and Inaccessible Islands, together with Gough Island, a cluster of volcanic islands in the far South Atlantic that form part of the United Kingdom overseas territory of Saint Helena, Ascension and Tristan da Cunha, roughly midway between Africa and South America. Vegetation is sharply zoned by altitude: coastal tussock grassland of Sporobolus mobberleyanus and Poa flabellata withstands constant salt spray, giving way between about 300 and 500 metres to fern bush dominated by the fern Histiopteris incisa, the tree fern Blechnum palmiforme, and the island Cape myrtle (Phylica arborea), with wet heath of Empetrum rubrum and Sphagnum peat bogs at higher, wetter elevations. The climate is cool-temperate and oceanic, with mean temperatures around 11 to 15 degrees Celsius and little seasonal change, though rainfall ranges from roughly 1,676 millimetres on Tristan to about 3,397 millimetres on Gough. The islands harbour over sixty endemic plant taxa and some of the world's most important seabird colonies, including the critically endangered Tristan albatross, and Gough and Inaccessible Islands are recognised as a UNESCO World Heritage Site and managed as an IUCN Category I wildlife reserve. For gardeners in mild maritime climates, the native island Cape myrtle (Phylica arborea) stands out as a hardy evergreen shrub or small tree adapted to wind and salt.

The Al-Hajar foothill xeric woodlands and shrublands wrap around the lower flanks of Arabia's Hajar Mountains, spanning Oman and the United Arab Emirates from Jalan Bani Buhassan in southern Oman north to Khasab and the area south of the Musandam peninsula. Below the cooler montane belt, this is a hot, hyper-arid country of rocky slopes and gravel plains, where Acacia tortilis is the dominant tree and the Al Saleel area holds one of the largest tracts of Acacia in Arabia. Wadis that hold a little more moisture support ghaf, wild almond, Wonderboom fig, and Christ's thorn jujube. Despite the harsh conditions the ecoregion carries a high proportion of rare and endemic species and remains a stronghold for the Arabian tahr, its flagship animal, alongside Arabian gazelle, caracal, and Blanford's fox. For gardeners in similar dry climates, its drought-hardy natives such as Acacia and jujube point to plants suited to heat and scarce rainfall.

The Al-Hajar montane woodlands and shrublands cover the highest reaches of the Hajar Mountains in eastern Arabia, spanning portions of northern Oman and the United Arab Emirates above roughly 1,200 metres, including the summit area around Jebel Shams. Vegetation shifts with elevation: olive and Sideroxylon (Monotheca) woodlands occupy the lower montane belt, while open woodlands of Zeravschan juniper (Juniperus seravschanica) characterize the high peaks, often mixed with wild olive and watered by acacias and figs along seasonal watercourses. Despite being wetter than the surrounding foothills, it remains a mountain desert with low annual rainfall, hot summers, and cool winters that bring occasional rain, hail, and snow to the highest ground. The juniper woodlands are a botanical stronghold, holding a large share of Oman's total flora along with a number of endemic plant taxa, and the range shelters the endemic Arabian tahr (Arabitragus jayakari) plus several endemic lizards; overgrazing by goats and camels and climate-driven juniper decline are leading conservation concerns. For gardeners, the native flora here illustrates how junipers and olives can anchor a drought-tolerant, cold-snap-resilient mountain planting.

The Alai–Western Tian Shan steppe stretches across the lowland and loess plains at the western foot of the Tien Shan and Alay mountains in Central Asia, spanning parts of Uzbekistan, Kazakhstan, Turkmenistan, Tajikistan, and Kyrgyzstan. It belongs to the temperate grasslands, savannas, and shrublands biome, where ephemeroid herb and grass vegetation dominates alongside coniferous Juniperus woodlands and relict fruit and nut forests; characteristic steppe plants include bulbous meadow-grass (Poa bulbosa), sedges (Carex), wormwoods (Artemisia), and wild ryes (Elymus). The climate is sharply continental, with hot, dry summers, mild winters, a wide annual temperature swing, and only modest precipitation. The region is botanically rich, with more than 2,000 recorded plant species, and it serves as a recognized centre of crop diversity holding important wild relatives of cultivated plants; the critically endangered Saiga antelope is its flagship animal. For gardeners, the area's native junipers and its wealth of wild fruit and nut relatives reflect a flora long tied to cultivation.

The Altai steppe and semi-desert spans parts of Kazakhstan, China, and Russia, forming a transition zone between the conifer forests of the Altai Mountains and the drier Kazakh plains, with the upper Irtysh River and the Tarbagatay Mountains as landmarks. Grasslands dominate, characterized by fescue and feather-grass (Stipa) along with hardy shrubs, while poplar and willow line the watercourses. The climate is sharply continental, with short warm summers and long, cold, dry winters (a humid continental, warm-summer Dfb type). The region's dry grasslands support birds of prey, including endangered steppe eagles, saker falcons, and eastern imperial eagles, alongside the demoiselle crane and mammals such as Altai marmots and the elusive Pallas's cat. Much of the ecoregion remains lightly developed and used mainly for livestock grazing, though overgrazing and agricultural pressure are the main threats, with formal protection still limited.

The California Central Valley grasslands fill the long lowland between the Sierra Nevada to the east and the Coast Ranges to the west, spanning the Sacramento Valley in the north and the San Joaquin Valley in the south. The climate is Mediterranean, with most rain falling in winter and conditions growing drier from north to south and on the western, rain-shadowed side. Historically a mosaic of perennial bunchgrass prairie, oak savanna, vernal pools, and riparian woodland, the region is now largely converted to farmland and dominated by introduced annual grasses. It is one of North America's most altered grasslands: less than 1% of native grassland remains and only about 4% is protected.