Re: Brooklyn tree/Loosestrife

> Date: Tue, 18 Jul 2000 11:32:59 -0400
>  From: Lowery@zeonchemicals.com
  
> >  I'm curious as to what makes this plant spready?

Val, 
Good question!  Purple Loosestrife spreads because it is a very prolific seed 
producer and also reproduces by underground stems.  Even if it is not a 
problem in your area, seeds from local plants probably travel down the river 
where they create trouble elsewhere.  

Here are more details from the Plant Conservation Alliance's Alien Plant 
Working Group at http://www.nps.gov/plants/alien/fact/lysa1.htm

>>
Lythrum salicaria L.  

METHODS OF REPRODUCTION & DISPERSAL: Purple loosestrife enjoys an extended 
flowering season, generally from June to September, which allows it to 
produce vast quantities of seed. The flowers require pollination by insects, 
for which it supplies an abundant source of nectar. A mature plant may have 
as many as thirty flowering stems capable of producing an estimated two to 
three million, minute seeds per year.  

Purple loosestrife also readily reproduces vegetatively through underground 
stems at a rate of about one foot per year. Many new stems may emerge 
vegetatively from a single rootstock of the previous year. "Guaranteed 
sterile" cultivars of purple loosestrife are actually highly fertile and able 
to cross freely with purple loosestrife and with other native Lythrum 
species. Therefore, outside of its native range, purple loosestrife of any 
form should be avoided.  

ECOLOGICAL THREAT: Purple loosestrife adapts readily to natural and disturbed 
wetlands. As it establishes and expands, it outcompetes and replaces native 
grasses, sedges, and other flowering plants that provide a higher quality 
source of nutrition for wildlife. The highly invasive nature of purple 
loosestrife allows it to form dense, homogeneous stands that restrict native 
wetland plant species, including some federally endangered orchids, and 
reduce habitat for waterfowl.  

DISTRIBUTION IN THE UNITED STATES: According to the U.S. Fish and Wildlife 
Service, purple loosestrife now occurs in every state except Florida.  

HABITAT IN THE UNITED STATES: Purple loosestrife is capable of invading many 
wetland types, including freshwater wet meadows, tidal and non-tidal marshes, 
river and stream banks, pond edges, reservoirs, and ditches.  
>>

--Janis

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