Looking for the Green

Pussy willow catkins, Longenecker Horticultural Gardens shrub trials

Pussy willow catkins, Longenecker Horticultural Gardens shrub trials

The March 12 tour (which took place five days before St. Patrick’s Day and seven days before the Spring Equinox) had the theme of “Looking for the Green.” My interpretation of looking for “the green” includes all seasonal Spring activity—I’m not committed to green only!

Our first tour stop was not, actually, related to green but rather to magenta and golden yellow. The hazelnuts (Corylus americana) were in full and spectacular bloom. It’s very possible to walk by a hazelnut without even noticing the “female” flowers. Although a brilliant magenta color, all that is visible is the tiny, ribbony styles/stigmas, just a few millimeters in diameter, emerging from buds on the branches. The magenta parts are really just the part of a flower to which pollen sticks and is then transported down into the ovary to form seed. The male parts are mature now, too, of course. If you bump your sleeve into these catkins, you will be covered in a yellow powder: pollen. These catkins were formed last season and are held tight and compact . . . until now, when they elongate and mature, releasing the pollen within. If you have started with spring sneezing already, you can point your finger at the hazelnut bushes.

Our next stop wasn’t green, either, but, instead, silver and yellow: the pussy willows in Longenecker. The row of willows is in partial bloom, with some pussy willows exposing yellow pollen while most show only the more durable silvery down. There’s no single species that is a “pussy willow.” Rather, the term is applied to several willow species (of which there are many) that produce the furry cat-like (you may need to engage your imagination) structures. As a child, I would gather these little furry buds and snuggle them into matchbox beds, tucked into tissue.

We checked in on events on the Icke boardwalk—as expected, overall, but there was more ice remaining than we expected.

Continuing onward, skunk cabbage–bound, the group brought up a few questions about tree identification in winter—which is a favorite topic of mine! We compared the dramatically different textures of the tree trunks of different species—black cherry vs. shagbark hickory vs. beech, for example. We also compared some more subtle differences—a particularly shaggy sugar maple vs. a not-too-shaggy shagbark hickory.

The skunk cabbage spathes are open, with the reproductive parts visible inside. Skunk cabbage are thermogenic, as are (what we usually call) “warm-blooded” animals. They have metabolic pathways that “burn” energy to produce heat. This is known as “uncoupling.” Usually, metabolic pathways are “coupled” with a product. In other words, an energy-releasing reaction is coupled with an energy-requiring reaction, resulting in a biochemical product. If “uncoupled,” then the energy-releasing reaction can just release heat. The heat is thought to protect the plant tissue against the cold, provide a microclimate for pollinators, and help to spread their skunky smell, which attracts pollinators.

We did, indeed, see plenty of green. Aside from the skunk cabbage (which, in fairness is as purple as it is green), we saw lush and reproducing mosses, basal rosettes of biennial and perennial plants, watercress (non-native and somewhat invasive, but, nevertheless, green), and other greenery.

Our tour start was marked by a lovely aerial display from three red-tailed hawks and the tour end was marked by the flight of three sandhill cranes. In all, a lovely Arboretum adventure.

As for the questions that we collected during the tour – here’s what I have to report so far:

  • I had mentioned that I didn’t think that silver maple (Acer saccharinum) was native, specifically, to the Madison are, but I was incorrect. According to USDA Plants database, silver maple has a much broader native distribution than I realized—from the “middle-ish” of the U.S, north-to-south, and eastward, as well as California and Washington state and much of Canada. The distribution shown in the USDA map, however, has me scratching my head. Some of it seems odd, like that silver maple would be native to Ontario and Saskatchewan but not Manitoba (which is right in between the two). Ditto for Oregon.
  • We admired the gigantic trunk of the silver linden (Tilia tomentosa) in Longenecker. It appears that a gigantic trunk is not a typical characteristic of this tree. The silver linden is a Eurasian species, planted in the U.S. as a resilient garden or street tree. I will see if I can find out any more about the factor(s) that may have contributed to the gigantic trunk of the specimen in Longenecker.

—Sara Christopherson

 

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