What’s wrong with planting non-native plants in an urban setting?

Why do ecologists argue for native landscaping?

Key Facts: 1) introduced species cause about 35 billion dollars in environmental damages per year (control costs, damages, etc)

2. About half of all the cases of species threatened with extinction involve interactions with introduced species (most in conjunction with habitat change)

3. ‘Accidental’ release of ornamental speciesaccount for about half of the non-native invasive plant problems.

Myrtle spurge exits the garden and heads for the meadow...

Myrtle spurge can ‘monoculture’ and displace

Native species.

Example of ‘ornamental plant ‘gone wild’. Myrtle spurge, still sold nationally…is spreading across the Colorado Front Range

Same site, revisited, 40 hours of labor later

Dalmatian toadflax, may be controlled by a single biological control agent, the weevil Mecinus janthiniformis.a;

Toadflax growing near Missoula, MT

Far too abundant and widespread for either mechanical or chemical control….

Species to watch in Colorado:Dames rocket, Hesperus matronalis, a riparian invader of Colorado

Purple loosestrife, Lythrum salicaria, the wetland invader

Boulder Open Space is still trying to eradicate this species.

Foxglove, Digitalis purpurea, recently found miles from any homestead. The next purple loosestrife in Colorado?

Bouncing bet, Saponaria officinalis. Oxeye daisy, Leucanthemum vulgare

This roadside scene is repeated on at least twocontinents…(This photo isFrom Australia)

(Boulder County sponsored a weed pull for this species at Caribou Ranch)

“It is a common weedy plant that spreads by prolifically producing seeds, but rarely becomes aggressively invasive, since its seed require open ground to germinate …it is not a very competitive species.” (This appears to be changing!)

Common mullein, kept in gardens for medicinal reasons

Escaped ornamentals that, by law, must be eradicated in Colorado

Orange hawkweed Purple loosestrife Myrtle spurge

Early detection and eradication is a strategy that ecologists and weed managers agree upon.

We recommend a phase-out of non-natives wherever possible.

Spotted knapweed, known as the ‘wicked weed of the west’ is the purple flowering plant shown here and has been found in small areas of the Front Range.

Attempts are underway to eradicate this weed on the Front Range rather than simply control it. Other fairly abundant weeds on that eradication list include the escaped ornamental species, myrtle spurge.

Myrtle spurge