Purple Loosestrife 'Morden Gleam'

I grew a Lythrum hybrid in Minnesota. It was not the least bit misbehaved. When I dug it up, it did not regrow from bits of root left in ...Read Morethe soil. To this day I consider it an irreplaceable perennial in the garden. The invasion by Lythrum on the Minnesota river did not happen overnight. If you ignore a problem plant for fifty years, it is going to run amok. Some gardener planted it directly on the riverbanks. I don't know of any lakes overrun with it in Minnesota, so apparently birds don't carry the seed significantly.

FYI-
Lythrum Quarantine
WAC 16-752-400 - 415
purple loosestrife Lythrum salicaria
wand loosestrife Lythrum vi...Read Morergatum
It is prohibited to transport, buy, sell, offer for sale or to distribute plants, plant parts or seeds of Lythrum salicaria or L. virgatum into or within the state of Washington. It is also prohibited to transplant wildplants and/or plant parts of these species in the state of Washington.
The Lythrum quarantine applies to all Lythrum species including any hybrid cross and all named cultivars, including but not limited to plants with the horticultural names: morden pink, morden gleam, morden rose, the beacon, fire candle, brightness, lady sackville, Mr. Robert, Robert’s happy, roseum superbum, purple spire, rose queen, the rocket, dropmore purple and tomentosum.

Lythrum salicaria, L. virgatum, and all of their hybrids are responsible for a devastating amount of damage to North American wetlands. A...Read Mores stated above, even self-fertile hybrids can contribute hugely to the problem, by pollinating wild-growing stands.

This species is considered self-fertile. However, research has shown that sterility occurs only when no wild species are growing in the ...Read Morevicinity.

According to Armitage, when 'Morden Pink' or 'Morden Gleam' was planted near wild Lythrum salicaria the resulting seed was over 80% viable.