No tree symbolizes strength and longevity more than the mighty oak. It has been revered by people all over the world for thousands of years. The Druids would not meet for ritual without having an oak tree present. The masts of the sailing ships that brought the pilgrims from Europe were made of
Quercus robur, English Oak. Native Americans ground acorns into flour and used it as a main food source for their families.
For me personally, oaks have been a significant part of my life. They have helped sustain me both economically and emotionally. I have grown hundreds of thousands of them over my 35 year career as a propagator-grower. To be able to grow them is an honor. When I plant acorns and think about the possibility that my little ones could live to be 100, 200, or maybe even 300 years old... Holy Cow! It boggles my mind. What I do really means something!!!
We are blessed to have several native species growing in Wisconsin.
------ Red Oak Group ------
Northern Pin Oak, Hill's Oak, or Scrub Oak
60' tall by 45' wide
Northern Pin Oak is a scrappy species that tolerates tough, droughty conditions. It has very shiny, dark green leaves with deeply pronounced sinuses. Its foliage turns brilliant shades of red in the autumn. The distinctive striped, oblong acorns are an important food source for numerous animals. The federally endangered Kirtland's warbler uses the trunk cavities for nesting sites. Unfortunately, Northern Pin Oak prefers acidic soils, which makes it difficult for us to grow in our Jackson fields (though the pH can be managed in container production).
50-60' tall x 35-45' wide
Black Oak is very similar to the Northern Pin Oak in its cultural requirements. It has the same basic range in our state, being found throughout the acid sands regions of Southern and Northwest Wisconsin. Therefore it is also difficult for us to grow in our fields. It has similar foliage characteristics and acorns to Northern Pin Oak and readily hybridizes with it. It had been my mission for the last 20 years or so to try to find out how to distinguish these two species from each other in the wilds of Wisconsin. I practically drove my wife nuts while on vacation one year, stopping every 10 miles or so to look at the Oaks. It wasn't until about two years ago, when I was looking online at a taxonomy website, that I found the answer. Black Oak has fuzz on the dormant buds! Northern Pin Oak doesn't. That's it.
60-75' tall x 60-75' wide
Red Oak is the most common oak species in the woodlands of Southeast Wisconsin. It is distinguished by its large, pointy lobed leaves. The foliage turns a russet to bright red in autumn, usually late October or early November in our area. Its acorns are relatively large being ¾"-1" long with a shallow cap. Trunks on old trees have a distinctive deeply ridged black bark. Red Oak is a fast growing tree that will caliper up quickly if soil conditions are to its liking. It prefers a rich, moist, well-drained soil with an adequate mulch layer over its root system. At Johnson's Nursery we select only alkaline soil-tolerant seedlings and only pick acorns from mother trees that produce the most tolerant seedlings.
Quercus rubra is a highly desirable timber tree for use in cabinet making, paneling, flooring, and furniture among other things. Deer, squirrels, and various birds love the acorns, with turkeys being major consumers in bumper years.
*All species in the Red Oak Group are susceptible to Oak Wilt, especially Northern Pin Oaks and Black Oaks. If you know this vascular fungal pathogen exists in your area, we recommend selecting trees from the White Oak Group*
------ White Oak Group ------
50-80' tall x 50-80' wide
This tree, along with Red Oak, is perhaps the most important oak species in our Southern Wisconsin forests. The White Oak is common in our pre-settlement forests and can be easily distinguished from other oaks by its round lobed leaves and light, ash gray bark from which it gets its name. From a distance, the tree's bark can almost look white in comparison to other trees in the woods. Acorns on White Oak are a chocolate brown color when ripe, with a shallow cap that has bumpy scales. The leaves are almost bluish-green (when healthy) and often turn a bright red to wine red color in the fall.
White Oak wood is one of the most useful woods we have in our forests. It is used for furniture, flooring, boat building, wine and whiskey barrels, and cabinetry. It is a very tough wood, resistant to water, reasonably priced, and is prized by woodworkers.
Growing this species can be very difficult and for this reason is not readily available in commerce. The trees are very particular about their nutrition. It is not easy to keep good green leaves on this tree. They often get chlorotic (yellow) showing various degrees of nutrient deficiency, so you must have a rich, well-drained soil full of natural soil organisms. I have been most interested in working with various strains of this species that have superior growing capabilities. We have been advancing slowly with this work and are finally seeing some nice looking plants in the nursery.
70-80' tall x 75-90' wide
If I could have only one tree in my yard here in Southern Wisconsin, it would be a Bur Oak. To me, it is the tree that defines our area. You can find 300 year old specimens in this part of the country. The state champion is in Dousman, Wisconsin and is nearly 100' tall and over 100' across. When I stand under this tree it feeds my soul in a way that is better than going to church.
Quercus macrocarpa gets its name (
macro meaning large and
carpa meaning fruit) from the fruit (acorns) that can be very large in this species. I have collected acorns from a Missouri seed source that were the diameter of a quarter. Here in southern Wisconsin they are typically the size of a dime up to a nickel. The common name Bur Oak comes from the bur-like fringing on the edge of the acorn cap. The acorns are a prized food for squirrels, deer, blue jays and crows, as well as chipmunks and mice.
Bur Oak is a large tree that is adaptable to many different situations in Wisconsin, from the Central Sands region to Southeastern heavy clay soils. Because of this wide range of adaptability, it is an easy addition to the landscape (if you have the room). I have identified several of these ecotypes for production at Johnson's Nursery.
Customers often have concerns about the "transplantability" of Bur Oak and fear that it is too slow growing. But at Johnson's Nursery, it has been an important mission of ours for over 30 years to improve the root system quality of oaks. We have accomplished this through various root culturing techniques that we use early on in the tree's life. These growing practices ensure the trees are able to be successfully transplanted to your site. We also collect our own acorns and select the most vigorous-growing seedlings. A Bur Oak whip planted in the fields will be a harvestable size in about 3 years. Once the tree is established in your yard, you can expect a foot or more of growth per year.
Swamp White Oak
Hybrid Swamp White Oak
Quercus x schuettei
50-80' tall x 50-80' wide
As the name implies, this species naturally occurs in low lying, flood prone areas. Near the nursery, we see it growing right next to a cattail swamp, a little higher up from Winterberry and Speckled Alder. This should give you an idea of their tolerance to wet conditions as well as their requirement for acidic soil.
One of the best ways to distinguish Swamp White Oak from other oaks is its fruits. The tree has 2-4" long fruit stalks (peduncles). The acorns are usually polished-looking and have a light brown to tannish color. Leaves on Swamp White Oak are a dark green above and white to grayish-green underneath--thus the name
. One of my favorite distinguishing characteristics is its peeling bark on 1.5" to 2" branches up in the canopy of the tree. Swamp White Oak has been a favorite for use by municipal foresters in our area because of its ability to transplant easily. It probably has the most naturally fibrous root system of all of the native oak species we grow.
Swamp White Oak wood is used for many of the same purposes as White Oak, but is generally considered of lower quality because the wood has many more knots in it due to the tree's habit of holding onto dead branches. This species' acorns are an important food source for such animals as ducks, turkeys, deer, and various song birds.
When it comes to Swamp White Oak, our biggest concern has become the species' alkaline soil tolerance. Because the nursery has pH values ranging from 7.2 to 8.0, trees of this species will often become chlorotic under such conditions. For this reason, we collect acorns from specific mother trees both in the nursery and in the wild that produce alkaline-tolerant seedlings. What we have found is that many of these mother plants are actually hybrids of Swamp White Oak + Bur Oak =
Quercus x schuettei. These hybrids look so similar to regular
Q. bicolor that we suggest switching to the hybrid for better success in establishing a beautiful specimen.
50-60' tall by 50-60' wide
is a very distinctive oak. Its leaves resemble those of a true chestnut (
) with a coarsely-toothed margin. Each tooth curves in slightly and comes to a point. The foliage is a lustrous, dark green or yellow-green on the top surface and whitish below. The acorns are typically small in comparison to our other native species, usually being less than .75" long. The acorns turn a yellowish color as they ripen and develop dark brown vertical stripes as they mature, eventually turning a rich dark chocolate brown color. Like most oaks, they don't bear heavy crops every year, but Chinkapin acorns are even less reliable. Only once every 6 or 7 years you get a bumper crop that allows you to pick them off of the ground. You typically have to use equipment to get up into the trees to pick them before they fall and before the many connoisseurs of these low-tannin acorns eat them. Squirrels, chipmunks, mice, blue jays, crows, and deer all love these nuts. I think they prefer them over anything else. They must taste really good to a certain palette, but I tried them myself one time and was not impressed. Perhaps I should have prepared them a certain way, or I should be a squirrel. It requires more research.
Chinkapin Oak is incredibly adaptable and have the widest native range of any other North American oak species, over nearly the entire Eastern U.S. from Vermont to Georgia to Texas and up to Minnesota. There are even populations of this species native as far west as New Mexico and into Mexico itself. The tree thrives in inhospitable sites as well as pristine woodlands.
Chinkapin Oak is a calceophile, meaning it loves high pH soils. This tree has tremendous potential as a street tree--it is adaptable and the animals will clean up the acorns. Even though it can grow just about anywhere, Chinkapin Oak is the rarest of the native oaks that we grow at Johnson's Nursery. It is listed by the State of Wisconsin as a species of Special Concern because of the low number of plants in the wild. Pre-settlement trees in the Southeastern part of the state seem to be located only at old Native American settlements. My personal theory is that the Native Americans brought the acorns to the Southeastern part of the state when they moved here from points farther south and east.
Just as the squirrels plant the acorns to feed their bellies, I must plant acorns to feed my soul (and pocketbook). George Bernard Shaw wrote, "Think of the fierce energy concentrated in an acorn! You bury it in the ground, and it explodes into an oak!" Oaks have a way of connecting with people through their strength, durability, and majesty. Try to find room in your hearts and yard for at least one!