C. sepium and other "regional" invasives
- Subject: C. sepium and other "regional" invasives
- From: B* B*
- Date: Tue, 24 Jul 2001 06:40:00
David Feix wrote:
>The white flowering morning glory I saw in Seattle was
>definitely not the common bindweed, Convolvulus
>arvensis,
[tongue somewhat in cheek here]
Nope, it's worse than that!
>The vine I was asking about, and has been
>tentatively identified by Diane as Convolvulus sepium,
>is a much larger growing vine with larger leaves and
>flowers which are also much larger, about 3 to 4" in
>diameter, pure white in color, and on a vigorous vine
>with deep green leaves and thick stems more similar in
>appearance to the common Blue Dawn Morning
>Glory/Ipomoea acuminata.
Yep, that's the beast. It was Convolvulus sepium; now it's Calystegia.
>It was also equally at home
>in full sun or shade, blooming in both exposures.
Hence its evilness!
>I would never advocate planting of common bindweed,
:) And doubless you would never advocate planting any other nasty invasive.
For all I know, C. sepium, or "hedge bindweed", might be better behaved in
other places. But in the Northwest it is a monster. Several plants are
listed here as invasives, which are more innocuous elsewhere.
>The White Morning Glory I found interesting in
>Seattle; C. sepium?, was the one I was asking about
>with regard to seeding around or rooting from stems in
>contact with the ground.
Yes and yes. :) And it creates a brittle underground spaghetti of roots.
(Which I have heard are edible but tasteless.)
>It was apparent that it is
>wide spreading and can be a nuisance from that
>standpoint, but I didn't know if it was also invasive
>in the sense that it could spread into other areas by
>seed or self rooting as well
All you have to do is drive down Highway 99 and see the huge banks of Queen
Anne Hill, on which grow two plants: Himalayan Blackberry and "Morning
Glory". Hey, at least they kill out the English Ivy (the other serious
invasive here).... "Battle of the Titans"!
You mention I. acuminata - and here I envied you all being able to grow it
down there...
>I notice that the current
>Heronswood mail order catalogue limits some plants to
>local sales only, and will no longer ship certain
>items to warmer, milder areas like Florida or Hawaii.
Yep, and check the vining Lonicera listings - they mostly end in "mindful of
possible biological invasion." :)
>I would suspect that Convolvulus sepium might be a
>similar case, but was hoping to find out what its
>exact liabilities were in the Seattle climate. It
>might be an invasive unwanted plant if grown in an
>adjoining neighbor's garden, but could also be very
>useful as a tough non irrigated flowering vine for a
>freeway divider or to screen a junkyard, as an
>example.
It was originally brought in as an exotic. It does grow in northern
Arkansas where my mom lives, but she has only been able to find it once. So
obviously under Ozark conditions it doesn't seem to be a threat at all. But
here...just think, the seed that spawned the writhing mass next door,
probably originated in some median strip.
(BTW did you notice the Buddleia japonica that pops up all over the town,
even in highway median strips?) :)
>High on the list of
>exotic plants to avoid are any that set viable seed
>which can be readily spread, whether by birds/animals
>or the winds, and in addition can survive and
>reproduce without supplemental irrigation in California.
Yep. I mentioned English Ivy - it generally doesn't set seed in the East,
but in the Northwest it grows vigorously and quickly "goes sexual", covered
with masses of black berries. These are spread by birds, and sprout in
local woodlands. There the plant carpets the ground thickly, creating "ivy
deserts", because almost no natives can compete. There is a strong case for
getting the plant listed as invasive here. Russian olive, giant cow
parsley, himalayan blackberry, St. Mary's thistle, purple loosestrife,
scotch broom, are just a few of the other plants that are serious problems
in the state. In Washington, some are invasive on one side of the Cascades
and not on the other (like Russian Olive and some of the Centaureas). I
have C. macrocephalum in my garden, the large yellow one, and it has never
once seeded itself, but I would never think of taking it east of the
Cascades.
I'm sure no offense was meant in the replies to your post either, and
certainly nobody truly familiar with any invasive would advocate planting
it. But the responses you got are an accurate indication of just how much
misery it has caused gardeners up here. And it is too bad because the
flower is gorgeous, even if you might have trouble in getting any Seattle
gardener to look at it objectively... ;) Oddly, this plant is not listed
here but I imagine it's because its eradication would not be enforceable. I
know I have tried for years, and only managed to keep it under control; if I
had to pay a fine for not getting it out, I'd probably be among the homeless
by now!
Bob
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