Zone 9 is a region of the United States where temperatures are generally milder than average, rainfall is moderate, and days are relatively long. The climate varies from place to place due to local geography and topography. These factors include elevation (mountains or lowlands), soil type (loess or clay loam) and water availability (riparian lakes or rivers).
In general, zones 8 through 10 encompass most of the northern half of the continental U.S. and southern California. The eastern third of the country is covered by zones 7 through 6, while the western third is covered by zones 5 through 4.
In addition to these broad geographic boundaries, there are many smaller areas within each zone; however, they all share common characteristics such as cool summers and hot winters.
The name “zone” comes from the fact that it was originally defined as a geographical area separated into five distinct regions based on climatic conditions. Today, the term refers to a range of different climates. Some places have only one zone, while others have several.
Zones 8 through 10 are characterized by warm summers and cold winters. Average annual temperature ranges from 80°F (27°C) in the mountains to 32°F (0°C) at sea level. The growing season is at least 200 frost-free days.
Zones 7 and 6 have cold winters and warm summers. The growing season in these zones is between 150 and 200 days long. Average temperatures range from 14°F (-10°C) at high elevations to 70°F (21°C) at low elevations.
Zones 5 through 1 encompass the areas with mild or warm winters and short cool summers. The growing season is at least 150 days long. Average temperatures range from 50°F (10°C) at high elevations to 77°F (25°C) at low elevations.
And although these zones aren’t based on rainfall, zones 1 through 4 are generally much drier than zones 5 and 6.
Virtually all cities and counties in the U.S. have been assigned to one of these zones. So when planning a landscape, it is important to determine which zone you live in so that you can choose plants that are suited to your area.
The following list shows the zones for cities and counties in the state of California:
Zone 1: above 4,000 feet (Mt. Whitney, Independence, Bishop, Old Man Mountain, Mammoth Mountain)
Zone 2: above 3,000 to 4,000 feet (Lone Pine, Shaver Lake, Owens Valley)
Zone 3: above 2,500 to 3,000 feet (Manzanar, Big Pine)
Zone 4: above 2,000 to 2,500 feet (Bishop, Lone Pine)
Zone 5: above 1,500 to 2,000 feet (Big Pine, Independence, Bishop)
Zone 6: above 1,000 to 1,500 feet (Bishop, Big Pine)
Zone 7: above sea level (Independence, Bishop)
Zone 8: below 1,000 feet (Bishop, Lone Pine)
Zone 9: below 500 feet (Bishop, Big Pine)
Zone 10: below 200 feet (Lone Pine, Shaver Lake)
(Courtesy of the USDA)
Now that you know your zone, you can narrow down your choices for native plants. Here is a list of some of the more popular ones. They are listed in alphabetical order:
Common Name: bristlecone pine Scientific Name: Pinus aristata Description: Needles are one to two inches long, dark green in color with a distinctive white stripe on the lower portion. Cones are 4 to 5 inches long and have thick scales. Growth habit is narrow and upright.
Sources & references used in this article:
Flowering trees in subtropical gardens by G Kunkel – 2012 – books.google.com
Flowering trees of Florida by IS Majnep, RNH Bulmer – 1977 – Auckland University Press
The foraging behaviour of a nectar feeding marsupial, Petaurus australis by MK Stebbins – 1999 – books.google.com
Small Flowering Trees Deserving Greater Use© by RL Goldingay – Oecologia, 1990 – Springer
Remnant Flowering Trees as Avifaunal Refuge in the Fringe Areas of Pakke Tiger Reserve, Arunachal Pradesh, India by D Creech – … of the International Plant Propagators Society-2012 …, 2012 – actahort.org
Taylor’s guide to growing North America’s favorite plants: proven perennials, annuals, flowering trees, shrubs, & vines for every garden by A Vishwakarma, A Kumar, M Samte, D Parbo… – Proceedings of the …, 2020 – Springer
Wyman’s gardening encyclopedia by B Ellis – 2000 – books.google.com
Altitudinal differentiation in growth and phenology among populations of temperate-zone tree species growing in a common garden by D Wyman – 1986 – books.google.com