Lichen on tree trunks may not be a sign of winter turning to spring, but they are more noticeable at this time of year. Some lilacs and yellowwood trees were covered so extensively with lichen that someone asked: could this kill the tree? Although various lichen species were covering a lot of bark, it would not kill or hinder these trees in Longenecker Horticultural Gardens. The lichen are simply using the tree as something to hold on to—a substrate. They attach themselves to the tree to gather light, moisture, and nutrients. You may also have seen lichen on rocks and the soil. Lichens are organisms composed of a fungus and some type of algae and/or cyanobacteria. Today, we were seeing plate-like lichen, called “crustose” lichen. Dominating the populations were a light orange, golden yellow lichen called powdery goldspeck (Candelariella efflorescens) and a pale grey green lichen called common greenshield (Flavoparemelia caperata).
The flowering of vernal witchhazel (Hamamelis vernalis) in the winter is always interesting. The flowers bloom from January to March. Its genus name, Hamamelis, means “together with fruit,” referring to the simultaneous occurrence of flowers with the maturing fruit from the previous year. Flower colors can vary. The plant we saw had many flowers—bright red in the center with short yellow strap-like petals. Longenecker Horticultural Gardens showcases various shrubs and trees that will grow in our climate. Coming at different times of the year, you can see what plants may look like at various ages, see what different species, hybrids, or cultivars look like, and at this time of year see which plants are interesting in winter.
Dogwood shrubs also provide interest in winter—they don’t retain flowers, but as the leaves and flowers drop off they reveal rich colors in their stems. We looked down the row of dogwoods with many shades of golden yellow to rich red bark. Hydrangeas shrubs occupy the next row over and don’t retain the color of their large, showy flower spikes, but if you don’t cut them back or wait until the spring they will provide an outdoor dried flower arrangement.
And—one more row over—finally some sure signs of spring! Pussy willows. The fine fuzzy silver-white hairs protect the pollen producing catkins. Even when it is fairly cold this fur coat can keep the developing pollen producing parts above the surrounding air temperature and aid in the development of the pollen parts that will soon emerge this spring.
In Longenecker Horticultural Gardens, the bench near the evergreen trees at the top of the hill is a popular spot to view the gentle slope of the gardens and the woods and some of the prairie in the distance. This view is brought to us by the glacial deposition and melting action as the glacier advanced 11,000 years ago. This feature is called a drumlin. You can ascend the steeper side heading east on the road from the Mills St. entrance and then proceeding down the gentler, longer slope toward the Visitor Center after passing the Wingra Woods parking lot, or by walking west through Longenecker Horticultural Gardens.
We were taking the opposite route, getting a little exercise going east from the Visitor Center up the slope toward Wingra Woods. We spotted an interesting tree, and many of us recognized the bark, which looked like the pale and brown peeling bark of a sycamore tree. We were partially correct—one of this tree’s parents is American sycamore (Platanus occidentalis). The other parent is the smaller Oriental planetree (Platanus orientalis). The offspring is named the London planetree (Platanus x acerifolia). Like many other plant breeds, the crossing of species was an experiment to achieve desired characteristics of a particular shape, color, or suitability to certain habitats, etc. One of the main goals of this hybrid was resistance to anthracnose, a fungus that often infects sycamores. Not only is this hybrid more resistant, it is also easy to grow, long-lived, and will tolerate compacted soils, droughts, and air pollution. In other words, it is designed to do well in urban areas. This trademarked cultivar is called the Ovation™ London planetree. It was first bred at the Morton Arboretum near Chicago.
I looked up the history of this hybrid after noting the genus and species information on the tree’s small metal tag. The tree has caught my attention before not only the familiar bark, but also the seed balls in winter: they are a little smaller than a golf ball, deep brown, and most still hang from the bare tree. It looked a bit comical. We guessed the sign of spring here would be when the leaves and flowers push the dense seedballs off their branches.
We headed across the street and down the north-facing slope in Wingra Woods. It’s always a delight to see the two springs along the lower trail on the south shore of Lake Wingra. Much of the lake is ice-free now. There are a lot of geese and ducks—the woods and the water make it a popular place for birds and there is regular activity by the springs. Today, we heard the usual chatter of chickadees, some nuthatches, a few woodpeckers, and a Cooper’s hawk in the distance. We paused at the springs to listen and look for a while. Several people took pictures of the water flowing through the bright green watercress.
I moved the group along as most had not seen or smelled skunk cabbage. So we headed east on the trail and found that within the last week many more skunk cabbages had emerged in the mucky soil around the stream that flows to the lake. Right now, the insulated apparatus called a spathe is most visible. It looks like a huge pointed pasta shell, a mottled deep red color, and has honeycomb insulation, like insulated window shades, to keep the flower parts warm. Inside the spathe is a bulbous structure where tiny white flowers will form and be pollinated by beetles and flies in late winter/early spring. They are attracted to the smell, like a mild skunk spray. There was a gentle breeze that helped carry the odor to us. As spring progresses, the skunk cabbage will grow large leaves that look like a loosely packed cabbage plant.