Wednesday, September 28, 2011

Signs of Fall

Every year, it's good to remind people that goldenrod is NOT allergenic. Goldenrod is golden as a means of attracting bees that then do the work of spreading the pollen, rather than the wind. The true allergen is ragweed, which blooms at the same time of the year as goldenrod and has inconspicuous green flowers--green because ragweed (Ambrosia artemisiifolia) is wind-pollenated and therefore doesn't need to attract insects with bright colors.

Walk along most any nature trail in Princeton this time of year and you're likely to see a shrub that is turning yellow a few leaves at a time. This is spicebush (Lindera benzoin), an important shrub for bird nesting and also for its lipid-rich red berries. Lipids are fats, and fat is a more concentrated form of energy than sugars and carbohydrates. Birds like to travel light, so high lipid foods are the best fuel for their migrations. Professional deer management in the township over the past decade has allowed spicebush to make a dramatic comeback in Princeton's forests.

Now is the the last chance to pull out Japanese stiltgrass (Microstegium vimineum) that may be invading your flower beds, before its seeds mature and fall to the ground. Stiltgrass is an annual introduced to the U.S. back when it was used as packing material for porcelain from Japan. At Mountain Lakes Preserve, it forms monoculture meadows on the forest floor. It uses a "warm season" growth strategy similar to crabgrass, sprouting from roughly a gazillion seeds late in spring, maturing in late summer. You'll find it growing in miniature in your lawn, or crawling 4 or 5 feet high, up and over other plants. This plant's a big, big problem if one's interested in promoting biodiversity, and the best way to keep it from becoming an ongoing nuisance in one's yard is to catch it early and pull it out before it drops its seed. If deer would eat it, some sense of balance could return to the local woods, but don't expect their taste buds to change any time soon, despite the presence of this hugely abundant food source. Read more here.

Persimmon is a native tree that typically bears fruit out of reach. This photo was taken thirty feet up, looking down from the new university bridge over Washington Road, between the chemistry building and the athletic fields. A couple more years growth and we'll be able to pluck the fruit from the bridge.

No comments:

Post a Comment