THE state Department of Transportation has wisely sought help from plant experts to research native vegetation for effective ground cover along state roadways.

The goal is to identify plants that will not need permanent irrigation systems, mowing and use of herbicides, reducing maintenance and environmental costs. Native plantings also eliminate the problems invasive species can cause.

Unfortunately, because of bureaucratic entanglements, a highly invasive succulent was recently put in along a Puuloa Road landscaping project.

The non-native species called the “;ice plant”; had been rejected for projects after the department learned that the South African introduction had cost California millions of dollars to remove.

The department said the project was designed in 2004, before problems with the ice plant were known, and that changes would have added costs.

While it's fine for the department to be frugal, officials may have made a penny-wise and pound-foolish decision. Ice plants easily reproduce through seeds generated year-round and by rootings of segments or shoots. They form solid mats that block other growth, compete for water and change soil acidity. Herbicides don't eliminate them; in most cases, the plants must be dug up, all of its parts removed to prevent regrowth.

The ice plant incident should be the department's last fumble. The program it is developing to list bad plants and make planting natives easier and cheaper is sensible. Kudos to Christopher Dacus, a landscape architect for the department, who proposed the idea five years ago when he joined the agency.