Bur Oaks on our 80 Acres

Much of the photography in this blog is taken on our 80-acre farm here on the edge of St. Joseph, in Central Minnesota. More than half of our land was too low or too wet to come under till, which means it has some remnant native plants. One of them is the Bur Oak. Indeed, the landscape of this part of Minnesota was once defined by the Bur Oak, as well as a whole system of native grasses and wildflowers. This ecosystem, or biome, we call the Oak Savanna. 

As I said in a previous post, the Bur Oak is a slow-growing tree, with a life expectancy of 200 years. Some have been measured to live 400 years, making them the longest living plants in our area.

This Bur Oak was about my height when we built our house in 1987. That makes it at least 35 years old. 

One aspect of the Oak Savanna is that the trees in it are spread out, allowing sunlight to penetrate the woodland floor. Such sunlight allows for a good many of prairie, or full-sun, plants to inhabit the a savanna. And of course the oaks will have a good many partial sun/partial shade (but not dense shade) native wildflowers under them. In many ways, a good savanna looks like a prairie with Bur Oaks in it. 

Because these trees grow slowly, their wood is more dense. So, square foot for square foot, these trees have stronger, heavier wood, which is why people like them for making things and for burning. The reason one sees "Oak Fire Wood" for sale is because an Oak log will put out more heat, and burn longer, than other lighter woods like Pine or Poplar. 

This Bur Oak is easily three feet in diameter, making it a two hundred year old tree. It has grown in a lower, wetter part of our land.

I'm guessing that there were many more oaks on our property at one time, but they were cleared to create tillable land and were used for construction. 

This cluster of Bur Oaks is unusual on our property. I assume a squirrel collected and stored acorns from the nearby Oak in the previous photo. Together they make up a nice little savanna in our wetlands. Because their acorns may have all come from the same tree, they are all of the same family, and therefore sharing similarities in structure, which I look for when I walk by them.

Native Plants that Provide Color in Winter

I love the look of Pin Oak leaves on the trees in winter. It is as though they're saying, "What's the rush? Spring foliage won't be coming until, well, spring." So, in the process they provide us with interesting texture and color on the horizon. 

I have a tree nursery. I deliver and plant balled and burlapped trees. I must say, I rarely get a request for a Red Oak or Pin Oak, the assumption being that they are Oaks, and thereby slow growing. But this is not the case in the Red Oak family. They grow as fast as anything. The White Oaks, on the other hand, grow slowly. But they live up to 200 years and more. Their cragginess, for lack of a better word, gives them a beauty all their own. They could be regarded as an ornamental tree, justifying their existence for sheer beauty alone (and not just for their utility in providing shade).   

Of course the red of the dogwood gives a very nice color in late winter and early spring. Pruning your dogwood will generate new shoots, and it is the new shoots that are the most red (while the older ones turn and stay green). A good time to prune them, or cut them down so that they re-sprout, is in late winter or early spring.

Few plants get a worse rap than the Eastern Red cedar. I grow them in my nursery and can't tell you how many customers scoff at them, sometimes refering to them as "scrub brush." 

Their virtues are several: they attract birds like no other tree, providing dense structure and stability for nest building. They are the only plant I can think of that appears to turn from their rusty summer color to a deeper green in the winter. We used one as a Christmas tree last year and, I swear, it turned greener after we cut it down and brought it in the house. They do best in full sun but will tolerate partial shade. 

They make for a wonderful plant in a prairie, complementing the grasses and wildflowers with height and texture. 

Winter Landscapes 2

The snow of winter is important for vegetative landscapes in cold climates, including prairies. It has the effect of insulating the ground, keeping the heat in and cold out. Likewise, it also serves to keep the moisture in the ground. Even though the turf is frozen, if exposed, evaporation happens and the soils dry. And of course the newly deposited seeds from the previous year need moisture to geminate. Moreover, certain native wildflower seeds need to "stratify." Most milkweed species, for example, need a cold/moist stratification to encourage spring germination. The thawing/freezing of late winter/early spring has the effect of bringing them out of dormancy.

This Milkweed husk adds texture to the winter landscape. Moreover, these husks have been completely divested of their seed, meaning they've been distributed out into the prairie, waiting for the freeze/thaw of spring to bring the seed out of dormancy.

It is not unusual to see these "Galls" on Goldenrod stems. In winter they add a glossy/waxy texture to the prairie. These galls are called by the Goldenrod Gall Fly, which injects it's larvae into the stem of the Goldenrod plant, providing food and shelter until the larvae hatch. Other insect species are known to eat the fly larvae in the gall before they hatch. 

The Goldenrod Gall Fly is quite small, not a good flyer, and lives a short life. They exist throughout all of North America. 

This lone Compass Plant is much more noticeable in winter and provides nice contrast to the shorter plants.

Winter Landscapes

Given that half the year in Central Minnesota our landscapes are dormant, if not snow covered, it is interesting how little we think about winter landscapes. Another of the many upsides of using native vegetation is that it enjoys a unique beauty in winter as much as it does in summer. Snow provides the perfect background to highlight the varied shapes, textures and colors of native grasses and wildflowers. White is also the perfect background for highlighting any object of art. Of course winter landscapes are subtle, and require our attention, but once we are sensitized to them, they afford us a beauty all there own.

The Grey Headed Coneflower here provides not only texture to the landscape, but food for birds. The heads you see in this photo that are not round are what remains after the birds have eaten the seeds. Interestingly, the stem is strong enough for small birds to perch upon, allowing them to eat the seeds. Since we started this prairie some 22 years ago, wildflowers are popping up throughout the farm, due to the birds spreading the seeds.  

Grasses too have interesting texture in winter, when they are dried out. This was taken right after a five-inch snow fall, but the grass is still upright. Particularly attractive is the Cordgrass, the grass that has the long, slowly curving  downward blades. 

It seems the birds don't care for the Monarda seed as much as they do the Grey Headed Coneflower. Nevertheless, Mondarda flower heads create a dappled effect upon the landscape as well as provides some foliage, one of the few plants that keeps its leaves through the winter. 

February is the month that one can see the cattails seed out.