Evergreens are one of the most popular types of tree species in the world. They are usually considered to be beautiful and have been used for centuries in many cultures around the globe. However, they do not always thrive well in certain climates due to their tendency towards being cold sensitive plants or having weak root systems. Some of these trees are so small that they cannot even survive in some zones.
Zone 7 is a climate where evergreens thrive. These trees tend to be tall and slender with large, round leaves.
Their bark is often grayish brown and their stems are typically white or cream colored. They are generally very drought tolerant and tolerate temperatures from zero degrees Fahrenheit to 120 degrees Farenheit (minus 40 C to plus 50 C).
In addition, evergreens are sometimes called “cold sensitivity” because they prefer cool weather. Although some evergreens may be cold-sensitive, others like the heat!
All of them require a minimum temperature range between 60°F and 80°F (16°C and 25°C) for optimal growth.
There are two types of evergreens: broad leaf and needle leaf. Both of these are native to various parts of the world although there are far more needle leaf evergreens, which tend to grow in colder regions.
Needle leaf evergreens are better adapted to cold weather than broad leaf ones, which cannot survive in freezing temperatures.
The most popular evergreen tree is the cone-bearing pine (Pinus). This is a tall, slender tree with long, green needles that grow in bundles of two.
Its branches spread nearly straight upward and its wood is used for building and furniture. One of the most popular types of pine trees is the Scots pine (Pinus sylvestris). The leaves of this tree are two to four inches long with each needle being one to two inches wide. Its wood is typically used for paper pulp and other low-grade paper products.
The Colorado blue spruce (Picea pungens “Glauca”) has a bluish cast to its needles, which are one to three inches long. These needles grow in bunches of five and are often used for Christmas trees.
Another popular evergreen is the white pine (Pinus strobus). Its greenish-gray, five-inch needles grow in bundles of five and spread out at the top of the branches. The wood of this tree is often used for furniture and building.
One of the oldest evergreens is the yew (Taxus). This tree has small, yellow-green leaves and red berries.
Its wood was made into bows for longbows by ancient Britons and is still used for this purpose today. Another popular needle leaf evergreen is the macarthur palm (Macarthur palm), so named after General Douglas MacArthur. This tree grows in clusters and has long, gray leaves that are serrated at the edges. It is often found in tropical regions.
Broad leaf evergreens are less common than needle leaf types but are just as interesting. The most common type is the holly (Ilex), which have flat, shiny leaves that vary in color.
They also have berries that grow in clusters and make a “jingle bell” sound when shaken. Most hollies are native to the eastern part of North America. They are popular plants due to their red berries and lack of prickles. Another broad leaf evergreen is the Christmas, or Sierra, pine (Pinus hydaspes) a tree with short, blue-green needles that grow in clusters of five. The fruit, or cones, of this tree are brown and grow in pairs.
Although many evergreens are native to colder climates, this is not always the case. Some, like the Chinese English holly (Ilex cornuta “Rotunda”) and the American holly (Ilex opaca) are well-suited to warmer areas.
These plants have glossy leaves and berries that vary in color. The berries can be red, yellow or green and grow in clusters. These plants can withstand dry conditions and pest infestations and are resistant to disease.
Evergreens are popular for a number of reasons. Many varieties offer food and shelter for birds, while others have qualities that make them useful for crafts and art projects.
No matter what the species, evergreens are an important part of the ecological web and should be appreciated as such.
Sources & references used in this article:
A systematic quantitative review of urban tree benefits, costs, and assessment methods across cities in different climatic zones by S Roy, J Byrne, C Pickering – Urban Forestry & Urban Greening, 2012 – Elsevier
Non‐structural carbon compounds in temperate forest trees by G Hoch, A Richter, C Körner – Plant, cell & environment, 2003 – Wiley Online Library
Leaf structure and function in evergreen trees and shrubs of Japanese warm temperate rain forest I. The structure of the lamina by PJ Grubb, EAA Grubb, I Miyata – The botanical magazine= Shokubutsu …, 1975 – Springer