For years we've had lantanas in mini tree form on the roof patio of our city apartment, see below,
and I was appalled to read one day that they have been outlawed in some countries as invasive plants. Here's a link to an article about the havoc they are wreaking in various places. I had really wanted a lantana because they bloom tirelessly throughout the summer and are a wonderful magnet for bumble bees, bees and butterflies, including the intriguing hawk moth (picture taken from Wikipedia, see here).
Link to Creative Commons licensing agreement which applies to this photo.
A hawk moth - rather unusual in our zone and with an uncanny resemblance to a humming bird - regularly visited the lantana (and the petunias) at about 4 p.m. all summer, delighting us everyday. The patio literally buzzes with activity due to this plant.
We are in hardiness zone 7, and the lantanas do not survive the winter outside, so I figure they don't pose that much of a danger here. I either take them inside starting in late November or purchase a new one in the spring.
The other shrub I wanted was of course the butterfly bush, Buddleia davidii, and in fact I've already purchased and planted a dwarf species, "Buddleia Flower Power".
Imagine my dismay on discovering that this shrub, too, is considered an invasive species in some places and is prohibited, for example, in Oregon. And it's on the black list of invasive species in Switzerland, right next door. In Germany there seems to be a border between areas where it survives easily (and I'm in that area) and areas to the East with a more continental climate, where it doesn't. But no official measures are being taken, and in fact, summer lilacs (as they are often called here), are very popular and widespread. I read that one of the reasons it became popular is that it could survive even on the postwar rubble of many Germany cities. But it is causing the German Railroad trouble, since it proliferates along embankments.
While researching I discovered that several other garden favorites here in central Europe are also considered invasive, including mahonia, Himalayan balsam (a kind of impatience), Japanese honeysuckle, and many others.
So I'd be interested to hear what all you gardening experts out there, especially at Blotanical, think about this. Am I violating a basic principal of good organic gardening by planting these shrubs in my garden? It's somehow hard to imagine that shrubs that are so obviously appealing to native fauna could be harmful.