Characteristics of North American Birch Trees
Birch species are generally small- or medium-sized trees or large shrubs, mostly found in northern temperate climates in Asia, Europe, and North America. The simple leaves may be toothed or pointed with serrated edges, and the fruit is a small samara--a small seed with papery wings. Many types of birch grow in clumps of two to four closely spaced separate trunks.
All North American birches have double-toothed leaves and are yellow and showy in the fall. Male catkins appear in late summer near the tips of small twigs or long shoots. The female cone-like catkins follow in the spring and bare small winged samaras drop from that mature structure.
Birch trees are sometimes confused with beech and alder trees. Alders, from the family Alnus, are very similar to the birch; the principal distinguishing feature is that alders have catkins that are woody and do not disintegrate in the way that birches do.
Birches also have bark that more readily layers into segments; alder bark is fairly smooth and uniform. The confusion with beech trees stems from the fact the beech also has light-colored bark and serrated leaves. But unlike the birch, beeches have smooth bark and they tend to grow considerably taller than birches, with thicker trunks and branches.
In the native environment, birches are considered "pioneer" species, which means that they tend to colonize in open, grassy areas, such as spaces cleared by forest fire or abandoned farms. You will often find them in meadow areas, such as where cleared farmland is in the process of reverting to woodlands.
4 Common Birch Species
The four most common birch species in North America are described below:
Paper birch (Betula papyrifera). Also known as canoe birch, silver birch or white birch, this is the species more widely recognized as the iconic birch. In its native environment, it can be found in forest borders across the northern and central U.S. Its bark is dark when the tree is young, but quickly develops the characteristic bright white bark that peels so readily in thick layers that it was once used to make bark canoes. The species grows to about 60 feet tall but is relatively short-lived. It is susceptible to borer insects and is no longer used widely in landscape design due to its susceptibility to damage.
River birch (Betula nigra). Sometimes called black birch, this species has a much darker trunk than the paper birch, but still has the characteristic flaky surface. In its native environment, it is common to the eastern 1/3 of the U.S. Its trunk has a much rougher, coarser appearance than most of the other birches, and it is bigger than the paper birch, sometimes growing to 80 feet or more. It prefers moist soil, and although short-lived, it is relatively immune to most diseases. It is a common choice in residential landscape design.
Yellow birch (Betula alleghaniensis). This tree is native to forests of the Northeast U.S. and is also known as the swamp birch due to the fact that it is often found in marshy areas. It is the largest of the birches, easily growing to 100 feet in height. It has silvery-yellow bark that peels in very thin layers--not the thick layers seen in paper birches, nor the very rough texture seen in river birches.
Sweet birch (Betula lenta). This species, also known in some areas as the cherry birch, is found native to the eastern U.S., especially the Appalachian region. Growing to 80 feet, it's bark is dark in color, but unlike the river birch, the skin is relatively tight and smooth but with deep vertical scores. From a distance, the impression is of a smooth, silver bark marked by irregular vertical black lines.
Dogwood branches on the lower half of the crown grow horizontally, those in the upper half are more upright. In time, this can lend a strikingly horizontal impact to the landscape, particularly if some branches are thinned to open up the crown. Lower branches left on the trunk will droop to the ground, creating a wonderful landscape feature.
Dogwood is not suited for parking lot planting but can be grown in a wide street median, if provided with less than full-day sun and irrigation.
Dogwood is a standard tree in many gardens where it is used by the patio for light shade, in the shrub border to add spring and fall color or as a specimen in the lawn or groundcover bed. It can be grown in sun or shade but shaded trees will be less dense, grow more quickly and taller, have poor fall color, and less flowers. Trees prefer part shade (preferably in the afternoon) in the southern end of its range. Many nurseries grow the trees in full sun, but they are irrigated regularly.
Flowering Dogwood prefers a deep, rich, well-drained, sandy or clay soil and has a moderately long life. It is not recommended in the New Orleans area and other heavy, wet soils unless it is grown on a raised bed to keep roots on the dry side. The roots will rot in soils without adequate drainage.
Eastern Redbud is a moderate to rapid-grower when young, reaching a height of 20 to 30 feet. Thirty-year-old specimens are rare but they can reach 35 feet in height, forming a rounded vase. Trees of this size are often found on moist sites. The splendid purple-pink flowers appear all over the tree in spring, just before the leaves emerge. Eastern Redbud has an irregular growth habit when young but forms a graceful flat-topped vase-shape as it gets older.
Scientific name: Cercis canadensis
Common name(s): Eastern Redbud
USDA hardiness zones: 4B through 9A
Origin: native to North America
Are your evergreens looking yellow or brown? This might be why…
Extreme temperature changes over short periods of time during winter months can leave evergreen trees looking a little yellow and sad. There are a number of different reasons an evergreen tree might be turning yellow/brown and/or dropping needles this time of year. Sometimes it’s perfectly healthy, other times it’s not. How do you tell the difference, and what should you do? Here’s a few tips:
Needle Cast: If your conifer (pine, spruce, fir, or juniper) is dropping needles, it may be a perfectly normal and healthy occurrence. If the needles that are dropping are only on the interior part of the tree while the needles toward the ends of the branches are still flexible, green, and firmly attached, then your tree is going through a process called “needle cast.” This process is kind of like deciduous trees casting off their leaves every fall – the needles deepest inside the tree no longer receive much in the way of sunlight as they are shaded by the newer exterior needles, so the tree drops them. This is totally normal and you should not be alarmed.
Sun Scald: If the needles on one side of the tree are showing yellow or brown coloration, but the other side of the tree still looks healthy, it could be suffering from sun scald. The exceptionally dry winter air combined with low soil moisture and intense sun causes the needles to dry out. The damage is often only present on the most exposed parts of the tree where prevailing winds or southern sun can have the greatest impact. Often, only the tip of the needle will be discolored while the base of the needle remains green.
Some of this damage may be inevitable, depending on the location of the tree, but it can be mitigated by good winter watering. For particularly sensitive evergreens like boxwoods, arborvitae, and oriental spruce, to name a few, a permeable fabric like burlap can be used to wrap the plants, providing a little extra protection. Trees can also be treated with Wilt-Pruf, a product designed to give evergreen plants an added layer of protection on their needles and leaves. Generally, this type of damage is only short-term. Only in extreme cases do we start to worry about the overall health of the tree.
Freeze Damage: If your tree is dropping needles or yellowing/browning uniformly around the entire plant, there’s a chance the recent deep freeze caused such a shock to your tree that the needles were damaged.
When plants go through such a rapid change in temperature, they don’t have time to undergo the physiological changes that help them tolerate the cold. Cell walls can rupture when they freeze and the dry air can cause damage more easily than would otherwise be the case. In instances like this, the damage will be most prominent on the outer parts of the branches, causing the tips to discolor and lose needles while inner needles that weren’t as exposed during the freeze remain green.
In these cases, the only thing to do is wait and see. It is possible that in the spring, the buds that have already formed on the tips of those branches will still produce a new candle (the growth from which new needles emerge). We encourage you to wait to prune until you are certain a branch has died, as cutting a branch that has a healthy bud on it will result in no growth next season. You can gently pinch the buds on damaged branches to find out if they’re still healthy – a firm bud is a healthy one, while a dried out dead bud will crumble between your finger tips. In this case, as with sun scald, the best treatment is a good deep watering 2 times a month through the winter when possible.
Crimson King Maple Tree
If you are looking to add an extra dimension of color to your summer foliage, the crimson king maple tree can be an excellent choice. A large, dense shade-tree, the crimson king offers rich burgundy foliage all summer long, changing to a brilliant gold for autumn. While it is not perfectly suited to all purposes, the crimson king adds an element of interest to most landscapes and makes a delightful addition to a park or garden.
Colorado Blue SpruceSpecies
The blue spruce, green spruce, white spruce, Colorado spruce, or Colorado blue spruce, with the scientific name Picea pungens, is a species of spruce tree. It is native to the Rocky Mountains of the United States.
Scientific name: Picea pungens
Biological rank: Species
Higher classification: Spruce
The names Colorado spruce, blue spruce and Colorado blue spruce tree all refer to the same magnificent tree—Pica pungens. Large specimens are imposing in the landscape because of their strong, architectural shape in the form of a pyramid and stiff, horizontal branches that form a dense canopy. The species grows up to 60 feet tall and looks best in open, arid landscapes, while smaller cultivars that grow 5 to 15 feet tall are right at home in lush gardens.
A slow-release fertilizer designed for trees helps keep your Colorado blue spruce healthy. Follow these guidelines when applying fertilizer:
Call your utility company before making holes in the soil around the tree so you don't hit any pipes or wires buried in the ground.
Because the tree's roots are fairly deep into the soil, you need to make small, 1- to 2-inch holes in the soil with an iron bar to a depth of 12 to 18 inches. The holes help ensure that the fertilizer reaches the roots.
Follow directions on the fertilizer label for your tree and mix the fertilizer with sand or compost to insert it into the holes.
Apply fertilizer once a year in the fall.
Damage From Pests
Colorado blue spruce is relatively resistant to pests, and they probably won't kill your tree, but they can do some damage. Look out for these insects:
Spider mites are the most serious pest your spruce may have, and they could affect the overall health of the tree. If the tree's needles turn yellow they may be infected. Examine the tree for the mites on the yellowed branches. If the tree is small, hose off the mites with a strong spray or use an insecticidal soap or a chemical insecticide for a large infestation. Follow the directions on the product.
Gall-forming insects come in a variety of types, but they all produce small bumps or growths that may look like miniature cones at the tips of branches. Galls will not harm your spruce.
Other pests that cause minimal amounts of damage include spruce budworm, spruce needle miner, pine needle scale and aphids.
Except for canker problems in the East, Colorado blue spruce doesn't suffer serious damage from diseases. If you live in that area, also plant a white fir (Albies concolor), which grows in zones 3 through 7.
These are the most typical diseases:
Canker turns needles brown before they drop off and produces white patches on branches that have been infected. To treat the disease, cut off infected branches and avoid overhead watering to keep the foliage of your tree dry. Sterilize your pruners after use to be sure you don't spread the disease to other trees.
Needle casts and rust both turn needles yellow or brown and cause them to drop off, but these diseases don't cause serious problems.
The hemlock tree is a coniferous evergreen tree. Information from the Arbor Day Foundation states there are three main types of hemlock tree: Western, mountain and Eastern. The Eastern hemlock is also known as Canadian hemlock, according to the University of Maine. Other names for the hemlock include hemlock spruce, weeping spruce, spruce pine and tanbark, according to Purdue University.
Hemlocks are large pyramid-shaped evergreens. Western hemlocks can achieve heights of 150 feet while Eastern hemlocks average 40 to 70 feet, but can get to 100 feet, according to the Arbor Day Foundation. Eastern varieties can be found in USDA hardiness zones 3 through 8; Western species are found in zone 6 but can adapt to other zones. The branches are pendulous, and cones are smaller than spruce or pine and more abundant. According to the USDA, the cones are short-stalked, brown with papery scales. Hemlock foliage does not change color in autumn but does have a light green to yellow color for new growth and a dark green for old growth, according to the University of Rhode Island. The bark is reddish-brown when the tree is young but darkens with age, says the USDA.
Hemlock trees are native to North America and can be found on both sides of the continent. The Arbor Day Foundation states that the Western hemlock can be found along the Pacific Northwest as far north as Alaska down through Canada. The USDA Forestry Service states that the Western hemlock can also be found through Washington, Oregon, Idaho, Montana and northwestern California. The Eastern hemlock, according to Purdue University, ranges from Ontario, Canada, down through Virginia and Alabama; it can also be found as far west as Michigan and Wisconsin.
Hemlocks grow wild in deep forests. Western hemlocks prefer dense shade and rocky soil, states the Arbor Day Foundation. The Canadian hemlock also is found on rocky ridges, hills and ravines. The Eastern hemlock is found along stream banks and where there are moist, cool beds, according to the University of Maine.
Hemlock trees are used for a variety of things. The Arbor Day Foundation states that the Western hemlock is an important part of the lumber industry, used for paneling, flooring and furniture. Hemlocks are also used for rayon yarns and tanning. Landscaping is another major use of hemlock trees, according to Ohio State University. The USDA also states that hemlocks are used in prevention of stream bank erosion. The University of Maine reports hemlock wood to be coarse, brittle when dry, strong and lightweight, but difficult to work with.
Throughout history hemlocks have been important. Tanning, basket-making, wool coloring, children's items and lining for pits were some of the uses Native Americans found for the wood, states the USDA. Other uses include poultices, liniments, windbreaks and structural support.
The common juniper's leaves are more like scales than coniferous needles. Some common junipers have spiny needle-like leaves that grow in whorls of three: The leaves are sharp-pointed and glossy green with a broad white band on the upper side. The adult tree shape is often narrowly columnar.
Common juniper bark is red-brown and peels off in thin, vertical strips. The fruit is a berry-like cone that evolves from green to glaucous to black as it ripens. The shrub and tree forms of common junipers are known as prostrate, weeping, creeping, and bushy.
Hardwoods are also known as angiosperms, broadleaf, or deciduous trees. They are abundant in the eastern forests of North America, though they can be found throughout the continent. Broadleaf trees, as the name suggests, bear leaves that vary in size, shape, and thickness. Most hardwoods shed their leaves annually; American holly and evergreen magnolias are two exceptions.
Deciduous trees reproduce by bearing fruit that contains a seed or seeds. Common types of hardwood fruit include acorns, nuts, berries, pomes (fleshy fruit like apples), drupes (stone fruit like peaches), samaras (winged pods), and capsules (flowers). Some deciduous trees, such as oak or hickory, are very hard indeed. Others, like birch, are fairly soft.
Hardwoods have either simple or compound leaves. Simple leaves are just that: a single leaf attached to a stem. Compound leaves have multiple leaves attached to a single stem. Simple leaves can be further divided into lobed and unlobed. Unlobed leaves may have a smooth edge like a magnolia or a serrated edge like an elm. Lobed leaves have complex shapes that radiate either from a single point along the midrib like a maple or from multiple points like a white oak.
When it comes to the most common North American trees, the red alder is number one. Also known as Alnus rubra, its Latin name, this deciduous tree can be identified by oval-shaped leaves with serrated edges and a defined tip, as well as rust-red bark. Mature red alders range from about 65 feet to 100 feet in height, and they are generally found in the western U.S. and Canada.
Softwoods are also known as gymnosperms, conifers or evergreen trees. They are abundant throughout North America. Evergreens retain their needle- or scale-like foliage year-round; two exceptions are the bald cypress and tamarack. Softwood trees bear their fruit in the form of cones.
Common needle-bearing conifers include spruce, pine, larch, and fir. If the tree has scale-like leaves, then it is probably a cedar or juniper, which are also coniferous trees. If the tree has bunches or clusters of needles, it is a pine or larch. If its needles are arrayed neatly along a branch, it's fir or spruce. The tree's cone can provide clues, too. Firs have upright cones that are often cylindrical. Spruce cones, by contrast, point downward. Junipers don't have cones; they have small clusters of blue-black berries.
The most common softwood tree in North America is the bald cypress. This tree is atypical in that it drops its needles annually, hence the "bald" in its name. Also known as Taxodium distichum, the bald cypress is found along the coastal wetlands and low-lying areas of the Southeast and Gulf Coast region. Mature bald cypress grow to a height of 100 to 120 feet. It has flat-bladed leaves about 1 cm in length that fans out along twigs. Its bark is gray-brown to red-brown and fibrous.
Northern white-cedar is a slow growing native North American boreal tree and its cultivated name is Arborvitae. It is often commercially sold and planted in yards throughout the United States. The tree is identified primarily by unique flat and filigree sprays made up of tiny, scaly leaves. The tree loves limestone areas and can take full sun to light shade.