Professor Lois Stack helps answer typical questions Signs of the Seasons volunteers may have when setting out to observe plants this fall. Lois is a professor of sustainable agriculture at UMaine and a Cooperative Extension specialist in ornamental horticulture. For years, she offered viewers gardening tips on the WABI-TV’s “Weekend Gardener” program and also wrote a regular horticulture column for the Kennebec Journal.
As we head into the fall monitoring season, do you have any general advice for trained SOS volunteers?
By this time of year, nearly all of our plants have finished flowering and even many fruits have fallen to the ground. But the calendar of plant events continues. Leaves will turn color and fall, some plants will die back to the ground, some plants will simply die. It’s the process of preparing for winter. That process differs a bit from year to year and documenting observations over time can help us understand if climate change, drought, temperature fluctuations and other occurrences are impacting our plants’ performance.
Why is fall observation as important as spring when everything is coming to life?
We’ve had a tumultuous summer in terms of weather, with a dry spring, heavy rainfalls, long periods of excessive heat, and now early frost. As of Sept. 18, I’ve already scraped my windshield on two mornings in western Hampden. The effects of all these events accumulate and stress becomes evident in the fall as the plants enter dormancy. Woody plants may turn color earlier and herbaceous plants may die back earlier. The general patterns are similar over time, but the dates change from year to year and that is important to document.
Let’s talk about the eight plants on the SOS Indicator Species List. Are there any special features or peculiarities people should watch out for?
This year, I’ve seen very abundant development of stolons, which give rise to new plants. That might be, at least in part, due to the spring weather patterns. But how will those new plants establish? When will they turn yellow and go dormant? Only monitoring will answer those questions.
Sugar maple fall color is largely a response to fall weather. Increasing colder nights combined with warm days produce the best fall color. Our sugar maples have plenty of water going into this coloration period, and this has the potential to be a spectacular fall color season if the daily weather patterns do their part.
Red maples grow in very variable conditions. They tolerate considerable soil moisture, but they also occur on dry slopes. Drier soils or root disturbance often cause early fall color in red maples. It might be interesting to watch red maples on two very different sites, just to compare the effects.
Dandelion flowers most abundantly in spring, but in a moist moderate-temperature fall, many dandelions flower fairly well in September. Be sure that you’re looking at dandelion (Taraxacum officinale), and not “fall dandelion” (Leontopodium autumnalis), which produces large numbers of smaller but similarly structured flowers.
Common lilac has already formed its flower buds for spring. You’ll see them mature into large, round buds as the season progresses. You can predict how abundant the flowers will be in spring 2014 by assessing the number of flower buds this fall. The leaf/stem buds are small and more pointed and are located just above this year’s leaves, along a long section of each stem. The flower buds are nearly spherical, and are only found toward the tip of each stem, usually only one or two pairs on each stem. Lilac leaves don’t have much fall color, but some plants may lose leaves early if they were heavily infected with powdery mildew – a whitish fungus that grows on leaf surfaces.
Forsythia has already formed its flower buds for spring. They’re mixed with the leaf/stem buds along the stems. Flower buds are similar to the others, but flower buds are about twice as large by the time they’re fully developed. Forsythias seems very predictable in its fall leaf drop. The leaves may turn purplish before falling.
Milkweed pods are not yet mature. In the coming weeks, they’ll increase in size, dry out, and then split open along one side to allow the seeds to dry out and drift off in the wind. They mature over a period of time, and some of the pods that formed latest in the season may not mature or open at all, hanging on the plants until spring.
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