Idaho Roadside Vegetation, by Eugene Ross, Roadside Manager, (208) 334-8416

Idaho's program approach to vegetation establishment emphasizes erosion control, soil and slope stabilization. This approach calls for diversity in selection of grasses, forbs and shrubs; chosen primarily for providing variable root depths rather than above ground top growth.

Because it is advantageous to select plant species that provide variable root depths, the Idaho Department of Transportation (IDT) is currently conducting extensive research into selection and availability of plant species (preferably native) adaptable to adverse environmental conditions associated with soil disturbance due to slices, road construction and roadside maintenance activities. The selection process involves picking the plant species that will grow in soil conditions (i.e. very steep road cuts) where top soil is non existent. Additional consideration in picking plant species is the mutual or symbiotic relationship that beneficial soil microorganisms (such as mycorrhize) have with plants that results in healthier plants especially during drought periods. Another important consideration is picking plant species seed that is available in sufficient quantities in the marketplace.

In conjunction with the plant species selection process, ITD is doing considerable work and research by using organic based (compost/seedmeal) and soil biological stimulant products that provide slow release nutrients and humus to start the process of rebuilding top soil in the disturbed areas. This process of feeding the soil before feeding the plant has resulted in remarkable results in rapid and sustainable vegetative growth.

Idaho's wildflower program fits in neatly with the total overall plant diversity concept and becomes a colorful part of the roadside plant community. Wildflowers are no longer planted in beds along the roadside except where extensive beautification/landscape projects are constructed.

These projects are usually constructed at interstate interchanges and entrances to cities. Idaho has also incorporated wildflower seeding/planting into its Adopt-a-Highway Program, where volunteer groups can plant wildflower seed on their adopted segment of road. This program, while having certain limitations, has been well received.

Additionally, a unique wildflower planting program involves Idaho Garden Club members utilizing ice cubes to spread native wildflower seeds in areas too rugged for conventional planting methods. It took the members about three years to perfect a planting method for the roadsides. They freeze the seeds in half full ice cube trays. After the cubes freeze, the half full trays are filled with water, which results in the seeds freezing into the middle of the ice cubes. The cubes are very useful. They provide a way to throw the seeds onto the hillsides. We should start seeing some results of this unique method in 1999.

Special recognition needs to go to Sherie Sweaney, our Volunteer Services Coordinator (Adopt-A-Highway, Operation Wildflower, etc.), and Bruce Drewes, ITD Training Specialist, who has an eye for what makes a winning picture.