Re: Gooseneck Loosestrife (was Propagation of)

All the information I have been able to find indicates that Lythrum
(not Lysmachia, aka Loose Strife) poses an extremely serious threat to
wetlands throughout North America. It crowds out native species and,
therefore, the dependent animal life as well. The monster is also very
difficult and expensive to control.

The noxious weed law in Kansas, the state where I live, only deals with
plants that threaten agriculture. Environmental concerns, such as
wetlands, are not addressed at all. I believe this is the case in many
other states as well.

The best information I have been able to find about sterile cultivars
is at UCONN IPM Loosestrife
http://www.lib.uconn.edu/canr/ces/ipm/general/biocntrl/notprty.htm.

Excerpt from the page:

     The Sterility Issue

     Horticultural cultivars of Lythrum, such as 'Robert', 'Morden
     Gleam' or 'Morden Pink' are described as being cultivars of
     Lythrum salicaria, Lythrum virgatum L., both from Eurasia, or
     the native Lythrum alatum Pursh. Taxonomists in North America
     have determined that Lythrum salicaria and Lythrum virgatum
     are the same and that they hybridize freely...

     ... Neil Anderson and Peter Ascher at the University of
     Minnesota determined fertility levels of 18 cultivars of
     Lythrum salicaria and Lythrum virgatum in a 1993 study. Their
     results showed that purple loosestrife cultivars are not
     sterile, but are, in fact, very fertile. Although most
     cultivars are self-incompatible, they can produce large
     amounts of seed when used as a male or female parent in
     making crosses.

     Gardeners sometimes comment that when they put one or two
     purple loosestrife plants in their flowerbeds, the plants
     never set seed. If both plants are of the same flower type,
     they are not compatible with each other and seedset will
     probably not occur.

     However, purple loosestrife is insect pollinated. When bees,
     wasps or butterflies visit these garden plants, the insects
     carry pollen to purple loosestrife plants in nearby wetlands,
     adding to the spread of this invasive species in natural
     areas. With one purple loosestrife plant producing as many as
     2.5 million seeds each year, an acre of purple loosestrife
     yielding up to 24 billion seeds per year, and seeds remaining
     viable in the ground for at least five years, even a few
     plants can pose a serious threat to the environment.
     even a few plants can pose a serious threat to the environment.


There is some more helpful information for the home gardener (including
control methods and alternative plant choices for the garden) at:

MN Sea Grant: Purple Loosestrife: What You Should Know, What You Can Do
http://www.d.umn.edu/seagr/exotic/purple/purplel.html

Why is Purple Loosestrife an effective invader?
http://www.science.mcmaster.ca/Biology/Harbour/PURPLEL/INVA.HTM (This
site has "before and after" photos if you want to see this thug's
handiwork.)

At 1:43 PM -0600 7/21/98, kvlykins@mail.atl.bellsouth.net wrote:
>>
>Susana wrote:
>
>> There are varieties that are infertile, which are recommended.  It
>>is a noxious weed in many states.
>
>I've read that these "infertile" ones have turned out to be fertile.
>Does anyone know where to get the facts on this?  I've always avoided
>it because we have wetlands nearby.

---
Peggy Enes (peggy@unicom.net)   Zone 5/6


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