A hardiness zone is a geographic area defined as having a certain average annual minimum temperature, a factor relevant to the survival of many plants. In some systems other statistics are included in the calculations. The original and most widely used system, developed by the United States Department of Agriculture (USDA) as a rough guide for landscaping and gardening, defines 13 zones by long-term average annual extreme minimum temperatures. It has been adapted by and to other countries in various forms.
Ulmus minorsubsp.canescens is a small deciduous tree occasionally known by the common names grey elm, grey-leafed elm, and hoary elm. Its natural range extends through the lands of the central and eastern Mediterranean, from southern Italy, the islands of Sicily, Malta, Crete, Rhodes and Cyprus, to Turkey, and as far south as Israel, where it is now considered rare and endangered in the wild. The tree is typically found amidst the comparatively humid coastal woodlands and scrublands.
Rhododendron macrophyllum, the Pacific rhododendron, California rosebay, California rhododendron, coast rhododendron or big leaf rhododendron, is a large-leaved species of Rhododendron native to the Pacific Coast of North America. It is the state flower of Washington.
Atriplex canescens is a species of evergreen shrub in the family Amaranthaceae native to the western and midwestern United States.
Atriplex confertifolia, the shadscale or spiny saltbush, is a species of evergreen shrub in the family Amaranthaceae, which is native to the western United States and northern Mexico.
Tiquilia canescens, the woody crinklemat or shrubby tiquilia, is a perennial, shrub in mid- to lower-elevation desert regions in the family Boraginaceae - Borage or the Forget-me-nots. It is found in the southwestern United States and Northwestern Mexico, in the states of California, Nevada, Arizona, Utah, New Mexico, Texas, Chihuahua, Sonora, and Baja California. It is a short, low-growing plant, seldom over 15 in tall.
Arctostaphylos canescens, common name hoary manzanita, is a species of manzanita.
Atriplex lentiformis is a species of saltbush.
Amorpha canescens, known as leadplant, downy indigo bush, prairie shoestring, or buffalo bellows, is a small, perennial semi-shrub in the pea family (Fabaceae), native to North America. It has very small purple flowers with yellow stamens which are grouped in racemes. Depending on location, the flowers bloom from late June through mid-September. The compound leaves of this plant appear leaden due to their dense hairiness. The roots can grow up to 5 m (16 ft) deep and can spread up to 1 metre radially. This plant can be found growing in well-drained soils of prairies, bluffs, and open woodlands.
Tetradymia argyraea is a species of flowering plant in the aster family known by the common names spineless horsebrush and gray horsebrush. It is native to western North America.
Tetradymia glabrata is a species of flowering plant in the aster family known by the common name littleleaf horsebrush. It is native to the western United States, especially the Great Basin and Mojave Desert. Its habitat includes sagebrush, woodlands, and scrub. It is an erect, bushy shrub growing to a maximum height over one meter, its stems coated unevenly in white woolly fibers with many bare strips. The narrow, pointed leaves are usually no more than a centimeter long and most occur in clusters along the branches. The inflorescence bears up to seven flower heads which are each enveloped in four woolly phyllaries. Each head contains four yellow cream flowers each around a centimeter long. The fruit is a hairy, ribbed achene with a pappus of bristles.
Conradina brevifolia is a rare species of shrub in the mint family known by the common name short-leaved false rosemary. It is endemic to Central Florida, where it is known only from the Lake Wales Ridge. There are perhaps 36 occurrences of the plant remaining, and 10 of these are likely to be destroyed as their habitat is fragmented in the coming years. About 15% of the Lake Wales Ridge, the only home territory of the plant, remains today, the rest having been cleared for development and citrus groves. Few of the extant populations have more than 25 plants. This is a federally listed endangered species of the United States.
Conradina etonia is a rare species of shrub in the mint family known by the common name Etonia rosemary. It is endemic to Putnam County, Florida, where it is known from about 8 populations on Etoniah Creek State Forest containing fewer than 1000 total individuals. It has a specific habitat requirement and the main threat it faces is destruction and degradation of its habitat. It is a federally listed endangered species of the United States.
Conradina glabra is a rare species of shrub known by the common name Apalachicola rosemary. It is endemic to Liberty County, Florida, where it is known from about ten populations. It is found only in a small area and it is threatened by habitat destruction. It is a federally listed endangered species.
Sophora tomentosa, also known as necklacepod, yellow necklacepod, and occasionally as silver bush, is a pantropical shrub or small tree in the family Fabaceae. It commonly ranges in height from 4 to 10 feet and often occurs in coastal conditions and near wetlands. The common name Necklacepod is derived from the characteristic string of seed pods that develop after its yellow flowers germinate into seeds.
Conradina grandiflora is a species of flowering plant in the mint family known by the common name largeflower false rosemary, or large-flowered rosemary. It is endemic to Florida in the United States, where it occurs on the Atlantic coastal ridge. Its distribution spans Brevard, Broward, Dade, Highlands, Indian River, Martin, Osceola, Palm Beach, Polk, St. Lucie, and Volusia Counties.
Atriplex nuttallii, also known as Nuttall's saltbush, is native to central and western North America. It has been treated by some botanists as a synonym of Atriplex canescens.
Calamovilfa arcuata, commonly known as Cumberland sandreed, is a species of flowering plant in the grass family. It is native to the southeastern United States, where it is found in river scour zones. Due to its specialized habitat, it has a highly localized range, found only on the Cumberland Plateau and in the Ouachita Mountains.
Hypericum tenuifolium, known as Atlantic St. John's-wort and sandhill St. John's-wort, is a species of flowering plant in the St. John's wort family, Hypericaceae. It is native to the Southeastern United States.
Hypericum suffruticosum, known as pineland St. John's-wort, is a species of flowering plant in the St. John's wort family, Hypericaceae. It is native to the Southeastern United States.
