Issue No. 129 - September 12, 2004
by Sue Sweeney
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| GOLDENROD: The goldenrod's blooming, so it must
be fall. Goldenrod's a lovely fall bloomer that's gotten an
undeserved bad rap as a major source of allergy-causing
pollens. While it’s not pollen-free, it’s not the really bad
guy. Goldenrod's a friendly, photogenic native, beloved of
birds, and bees, and other beneficial insects. There are at
least 130 goldenrod species in North America. There's even a
seaside variety and a white one (“silver rod’). It's a great
late summer garden plant, too. |
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Picture: One of our
beautiful native goldenrods (Solidago) with a
beneficial wasp (Bartlett Arboretum, Stamford CT August
2004) |
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The villains are some of those
easy-to-overlook weedy things with greenish flower
stalks. The worst is the wind-pollinated ragweed,
which blooms at the same time, and often grows in
the same place as goldenrod, and which also belongs
to the Aster (Composite) Family. And then there’s
ragweed’s close relative the ubiquitous mugwort,
which is also coming into bloom now.
RAGWEED: Starting with ragweed, not
only is it the source of much human misery;
but we have only ourselves to blame. All
ragweed needs to get started is
freshly-turned earth to expose the seeds
buried in the soil, and a bit of sunshine to
wake the seeds up. The seeds will wait in
the soil for 40 years for the right
conditions to come along before germinating.
Like poison ivy, ragweed’s what we call
an “enhanced species” because human behavior
gives it a major ecological boost. Ragweeds
thrive where the earth has been disturbed.
In a way, it’s Mother Nature’s revenge for
leaving her earth naked to dry out and
erode. Almost daily, I read yet another new
article about research confirming that we
should disturb the soil as little as
possible, and that we need to mulch, mulch,
mulch. mulch. |
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picture: common
ragweed just before the flower stalks rise.
(Bedford Street, Stamford CT September 2004)
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Ragweed, for example, didn't get out of hand
until the European settlers along the East
Coast cut down much of the forest and plowed
up the land. Indeed, once I read that
archeologists date the mud at the bottom of
the Long Island Sound by the ragweed pollen
count, which rocketed upwards in the 1800's. |
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picture: western
ragweed detail (Scalzi Park, Stamford CT,
2004) |
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There are a good 2 dozen kinds of ragweed;
our local ragweeds come in three basic
types: common ragweed (Ambrosia
artemisiifolia), western ragweed
(Ambrosia psilostachya), and giant
ragweed (Ambrosia trifida). The
common’s usual knee height or less and has
deeply cut “raggy” looking leaves. The
Western looks like the common only it’s a
lot bigger. The giant have rounded leaves
with 2 to 5 pointy-tipped lobes and can
reach shoulder height or more. The common
and giant are annuals; the western can be
annual or perennial, spreading by
underground roots. |
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Picture: leaf
samples from the giant ragweed (Morgan
Street, Stamford CT September 2004 |
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| The three ragweeds have very similar flowers. The tiny
flowers along the flower spikes are facing downward; so what
you see are the scalloped green flower bases with the flower
parts peeking out from underneath like a petticoat. The
giant ragweed has tiny gold-yellow flowers; the common ’s
are tan. |
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picture: close up view of
the flowers of giant ragweed (Scalzi Park, Stamford CT
September 2004) |
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pictures: L: common
ragweed viewed from a distance R: giant ragweed from a
distance
The giant ragweed’s flower stalks are
striking green candelabras dusted with gold;
the common’s are smaller and closer together so they like
more like a crowd of slightly curved green spires |
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| MUGWORT: Now for the mugwort (Artemisia
vulgaris), also called “common wormwood”. This one’s an
alien, so again, we only have ourselves to blame. It’s
another one of the Euro-Asian imported herbs that got out of
hand. Along long the East Coast, across the Midwest and in
the Northwest, you’ll see the silvery, plumy colonies of
mugwort along sidewalks, backyards, parking lots and
roadways where we’ve disturbed the earth. It’s related to
absinthe and sagebush (not the cooking herb known as
“sage”). |
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picture: form, leaf
and flower stalk of mugwort, (Morgan Street
Stamford CT 2004) |
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USES: Ragweed is useful to
non-humans. The oil-rich seeds are good bird
food, particularly in winter. Mugwort and
ragweed are used in homeopathic medicine.
Mugwort, in particular, seems to have a
number of useful herbal applications. For
example, it’s recommended as an herb for a
“sleep pillow” and it’s sold as a lice and
mite repellant for caged birds.
Invasive, common-as-mud, allergy-causing
mugwort is still sold in nurseries and
on-line. The variegated “Oriental Limelight”
highbred seems to be very popular. One of my
fellow Master Gardener Interns spotted it in
a Connecticut nursery this past week, at the
amazing price of over $10 a pot. (I wonder
what the hapless buyers thought when they
later saw mounds of it growing wild by the
parking lot!) |
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picture:
detail of mugwort mature leaf (note the pointed
tips) |
picture: detail of western ragweed
leaf
(note the deep cuts between leaves)
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picture: mugwort
blooming with Joe Pye weed (Scalzi Park
Stamford CT September 2004) |
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picture: giant
ragweed (Morgan Street Stamford CT 2004) |
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