Written by davethetreecenters • April 18 The Pine Trees of America #2
PART 2, THE 5-NEEDLE PINES OF AMERICA
In the first part of this look at our native Pines, we talked about how to identify pine trees with a reasonable degree of accuracy. In this part we will begin to take a look at the major species of pines, including points to look for in identification. With those basic methods and the information here you should be able to get pretty close to identify most pines you encounter. There are, though, almost 50 species of pine growing in North America. Many are rare, and only found in very limited areas. Others are wide-spread, and it is the top fifteen of those we will look at. In the next part we will look at our native 3-needle pines, and finish up with a final blog on 2-needle pines.
Pine species occupy specific parts of the country, and this is important to remember. If you are in eastern North America, and you find a wild 5-needle pine, then you must be looking at eastern white pine, Pinus strobus. Other 5-needle pines grow in other places, but not the east. Knowing which pines grow where you are is an important step in identification.
American 5-needle Pines, the Soft Pines
Let’s start with the soft pines, which are easy to recognize as a group. 5 needles in each bundle, and older bundles do not have a papery sheath around their base. If you live in the east the most likely native pine you will see is:
Eastern White Pine
This magnificent pine is a feature of the landscape of the northeast, and is the only 5-needle pine growing wild east of the Rockies. It grows around the Great Lakes, often clinging to rocky cliffs, and its profile, with a tall trunk and elegant upper branches is incredibly photogenic. More precisely, it can be found wild across an area from Minnesota through the Great Lakes to Newfoundland, and as far south as Georgia and a few high-altitude spots in Alabama.
Called Pinus strobus, it is also a wonderful tree for gardens and landscapes, and in older neighborhoods we often see striking specimens. The needles are soft and green with bluish overtones, and between 5 and 7 inches long. The bark is deeply furrowed and split into irregular plates, and a striking gray color. The cones are long and slender, no more than 2 inches wide when open, and about 6 inches long. They are light brown when mature, often with white clumps of waxy sap on them.
This tree grows rapidly, with young trees adding about 2 feet a year. Once a tree is 15 years old – which will probably be about 10 years after you plant a young one – growth speeds up, adding 3 feet a year, and within the next 30 years it could reach 100 feet, although in reality it will usually take longer than that. With age it slows down, but older trees of 100 feet are not rare, and 150 feet is seen widely in wild trees. It is likely that in the past wild trees topped 200 feet. Like most pines old trees develop long branchless trunks, topped by spreading, often wind-swept upper branches.
It is hard to imagine how numerous and extensive this tree used to be across the east. During the spread of Europeans westward in the 19th century trees were extensively logged for lumber. In a single year at the peak, 250,000 trees were sent just to Chicago lumber yards. Many millions of trees were cut down, and the wood was highly valued for the clean, knot-free planks that could be cut, quickly processed, and used everywhere density and great strength were not needed. Since wood was the major material for many things we today use plastics and cardboard for, much of the economy of America was built on the destruction of these forests.
For gardens, there are several excellent dwarf varieties that have been found. Here are some of the best and most useful for landscaping:
Dwarf White Pine – Pinus strobus ‘Nana’. This lovely bush grows into a dense, rounded plant about 5 feet tall and 8 feet wide, in about 20 years. The foliage is very attractive, and this tough and reliable plant can be used in sunny spots on dry soil. ‘Blue Shag’ is a superior selection, with especially dense form. An even more compact form is ‘Green Twist’, which is only a foot or two tall and wide, with unusual twisted needles.
Weeping White Pine – Pinus strobus ‘Pendula’. Very different, but still in a way dwarf, the Weeping White Pine is a form that has no desire to grow upwards. Instead it grows horizontally, or cascades under it’s own weight. It is generally grown as a unique ground cover over banks and slopes, but it can also be trained into a more upright, but still weeping, form. It isn’t particularly dwarf, and grows rapidly to be 10 to 20 feet across, with a mounding height of 4 to 6 feet if it isn’t trained to be taller. A striking and unique garden specimen.
Western White Pine
Virtually identical in appearance to Eastern White Pine, of you are west of the Rockies, this tree, Pinus monticola, is what you will be looking at. Growing between 3,000 and 10,000 feet above sea level, in mountain forests, it can be found from British Columbia through the northwest into northern California. The tree itself is narrower and more tightly branched than White Pine, but otherwise they are very hard to tell apart outside their natural habitats. As a garden tree it is more demanding, needing moist soil and cool climates, and not drought tolerant.
Limber Pine
A tree of the Rocky Mountains, and often called Rocky Mountain Pine, the Limber Pine, Pinus flexilis, is a smaller, often twisted tree, growing to no more than 50 feet tall, with a broad trunk and a rounded crown when mature. In the past it was logged extensively in Nevada and used for construction, but trees today are generally too twisted for top-grade lumber. It is exceptional among pines for growing better on alkaline soils than most, including White Pine, so it’s ideal if you have those kinds of soils. Very cold hardy – to zone 3 – it is a picturesque and attractive tree that is easy to grow across all cooler zones.
The needles are no more than 3 inches long, usually less, and a striking dark green. The needles feel smooth when pulled back and forth between the fingers, while white pines have rough-feeling needles. The cones are up to 6 inches long, but more rugged, with thick, slightly domed scales.
For garden use it’s a tough and fast-growing tree, and drought resistant. The best variety for garden planting is ‘Vanderwolf’s Pyramid’, a more compact selection growing no more than 30 feet tall and 15 feet wide. This tree is pyramidal in shape, with slightly twisted needles, and can be trained and pruned into a giant bonsai for an Asian garden in colder regions.
Sugar Pine
This tree of the west is the tallest-growing pine in the world, routinely reaching 130 to 200 feet, with the record tree, called Tioga Tower, growing in Yosemite National Park to a height of 275 feet. The needles are between 2 and 4 inches long, and the cones are the longest of any, between 10 and 26 inches in length, so this is a tree you are hardly likely to mistake for something else. Watch where you stand, because the cones can weight 4 pounds – not something you want landing on your head after falling 100 feet.
Known as Pinus lambertiana, it was named by David Douglas, the famous botanical explorer of the northwest. The nuts are edible by humans, and very popular with chipmunks, and the sap can be tapped like maple syrup, as native Americans did. Hardy to zone 6, but difficult to grow in gardens, needing a Mediterranean climate – mild winters and hot, dry summers – and very susceptible to white pine blister rust.
Bristlecone Pine
Often called Rocky Mountain Bristlecone Pine, because there are actually two closely-related species of bristlecone pine. You might ask yourself what this plant is doing here, since we said we would look at pines that covered significant parts of the country, and you certainly can’t say that about Pinus aristata. Found only in the San Francisco Peaks, a small mountain range running through parts of Colorado, New Mexico and Arizona, and only between 7,500 and 12,000 elevation, the range of this plant is very small. But its fame is world-wide, and it is widely grown by gardeners who have an acceptable climate. So it certainly deserves a place in our discussion.
A tree that can grow to 50 feet, with a flattened, irregular crown, in gardens it is normally a ‘dwarf’ evergreen, because it is slow-growing and large trees are only rarely seen outside its wild range. Distinctly blue-green, the curving needles are between 1 and 1½ inches long, in bunches of 5, and they stay on the plant for 10 to 17 years – something else remarkable about this amazing tree. The needles are spotted and blotched with white resin, giving them an exotic look. This is unique among pines, and often causes questions, since it can look like scale insects if you don’t know.
Cones are 2 ½ to 3 ½ inches long, purple-brown, and pointed, with bristle-like spine on the tip of each scale. Even young plants can have cones.
This tree is both slow-growing and long-lived. It adds 2 or 3 inches a year, with a maximum of 9 inches in ideal conditions. A 10-year tree could be 5 feet tall, and rarely more. It takes many years to reach 20 or 30 feet, and some old trees are among the oldest living things on the earth, with the oldest being 2,500 years old. That is exceptional, because most trees live no more than 1,500 years – certainly still a remarkable age.
In gardens the Bristlecone Pine is a great conversation piece, and a valuable addition to a conifer collection. It’s twisted form always attracts attention. When planting, consider that one day it could be over 20 feet tall and up to 15 feet across, and it cannot be safely transplanted when old. So leave some clear space around it, or with plants that could be one day moved.
