6:00am

Sat April 19, 2014
The Garden Report

Beware! Some Ornamental Plants Have A Sinister Agenda

The Russian Olive spread so fast in Colorado that its sale was banned.
Credit John / Flickr - Creative Commons

Any plant can become a weed if left unattended. There are some popular plants grown for their aesthetically pleasing features that will spread rapidly and destroy flora native to Colorado. 

Tom Throgmorton provides some alternatives to growing potentially invasive plants.

Thankfully there are many native plants with similar characteristics that won't run amuck in the garden.

Several years ago the fast growing Russian Olive tree was banned for sale in Colorado. The invasive species developed a pattern of pushing out native plants and trees. This is just one of many invasive flora that threaten Colorado’s fragile ecosystem.

"A less invasive alternative to Russian Sage is Leadplant, a Rocky Mountain native."

Russian Sage is another invasive species that blooms in from late July until the first frost, giving it an edge over other shrubs that bloom earlier in the season. The lavender flowers make it popular, but its tolerance to drought can cause this plant to spread rapidly.

After Russian Sage is established, it sends out sneaky roots that search for new water sources. These roots are strong enough to break through cracks in sidewalks. A single Russian Sage can colonize an entire area if the gardener isn’t diligent. 

A less invasive alternative to Russian Sage is Leadplant, a Rocky Mountain native. Once established it also survives on natural moisture, but if it gets more water from a drip system or sprinkler, it doesn’t take over. 

Leadplant has long, slender spikes of purple to blue flowers with a shorter bloom period than Russian Sage. It can extract nitrogen from the air and change it into useful nutrients for plants, actually building the soil for other plants in the garden. Spring pruning will develop a fuller shrub with more flowers.

Here are a few other plants I think should be grown sparingly. Barren Strawberry is a flowering ground cover that is so aggressive it takes over bluegrass. Creeping Yarrow is promoted as an alternative to a grass lawn because of its ability to take over. Painted Daisy left on its own takes over the perennials around it. 

There are many alternatives to these potentially invasive plants that support a healthy and balanced ecosystem.

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