University of Vermont Extension
Department of Plant and Soil Science
Anytime News
Article
THE STORY BUDS CAN
TELL
Dr. Leonard Perry, Extension Professor
University of Vermont
Watching when buds and then flowers
appear on specific plants from year to year now is being used to watch for
changes in climate. Knowing these dates
also can be related to the appearance of certain pests and diseases, so can tell
you the best times for control. The
study of such biological events is known as “phenology.” It is easy, once you know a few tips, and now
you can join a national network of gardeners and naturalists all sharing this
interest.
The appearance of robins in spring,
flowering of crabapples and lilacs, and the flowering of the cherry trees in Washington are all phenological
events. They respond to a combination of
climate factors such as temperature, rainfall, and daylength. Of course these can be measured separately,
but what I find fascinating about watching plants is that they are programmed
to combine all such factors to determine when certain events such as bud
opening occur.
Watching dates of biological events
each year is not new, dating back centuries to pre-agricultural times. The earliest written records were by the
Chinese in 974 B.C. The Japanese have
been monitoring peak cherry tree bloom for 1200 years. The famous Swedish botanist of the 1700’s
Linnaeus is considered a cofounder of the study of phenology. The word actually comes from the Greek words
for “study” of “appearances.” Another
cofounder of phenology was a British landowner, Robert Marsham, whose family
kept detailed records for a couple hundred years. Phenology has been handed down for years in
folklore, such as the saying relating leaf appearance
and rainfall. "If
oak's before ash, you're in for a splash. If ash before oak, you're in for a
soak."
Much of the current phenology
efforts can be traced back in part right here to Vermont, to the
research and network begun
in 1965 by Professor Hopp in the Department of Plant and Soil
Sciences. I took over this network in the early 1980’s,
at that time collecting bud and bloom data on certain selections of
lilac and honeysuckle. Since then, this network has been expanded
under Dr. Mark Schwartz at the University of Madison Milwaukee. The
current result is the National Phenology
Network where you can learn more about this science (www.usanpn.org).
You can become involved with many across the
country in their latest effort, Project Budburst (www.budburst.org).
The goal of Project Budburst is to
gather phenology data on several dozen native tree, shrub, and flower species,
over many years, and over all regions.
This data then can be used to track any changes in climate. Even if you just monitor your own plants
without sending this project the dates of certain events, you can get a feel
over the years of whether the climate in your own area is changing.
The website for Project Budburst has
some very useful information for your monitoring, with descriptions of
events
such as first leaf, full leaf, first flower, full flower, and end of
flower. There is a map you can click
your state for a list of possible native plants to watch for such
events. For instance, in Vermont there were about 30 possible plants
listed. Of these, some are more common
such as American linden, aspen, black locust, box elder, chokecherry,
dandelion
(yes, you can even monitor weeds!), yarrow, white pine, large-flowered
trillium, common lilac, paper birch, red maple, and red osier dogwood
(the
shrubby one with red stems).
When you pick a plant or two to
watch, make sure you chose a species and not a cultivar
(cultivated
variety). With lilacs, for instance,
depending on the cultivar, you might see first bloom from the second week of
May to the second week of June.
Many more details on phenology,
climate change, details and photos of all the plants, and how to participate as
a “citizen scientist” are on the Project Budburst website. Through participation in this program which
is easy, and doesn’t require much time (outside of what you probably already
are doing in watching your plants in spring and summer), you will be learning more
about your climate. You’ll be helping scientists in their
predictions, taking the “pulse of the planet.”
And you can begin to relate certain events, such flowers and pests. More information on this is available in Integrated
Pest Management checklists from the University
of Massachusetts
(www.umassgreeninfo.org/fact_sheets/ipmtools.html).
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