Construction of a National Herb Garden has been started on the grounds of the National Arboretum and it is expected to be completed this year. Financed in part by the Herb Society of America, it is to be the largest designed herb garden in the world, of about two acres.

"It will be a teaching garden, an historic garden, and a garden of the finest design," according to Herb Society officials, "and above all it will be a garden of inspiration and continuity and affection."

The herb garden will be located opposite the terrace of the Arboretum's Administration Building, within a large, lovely meadow.

One section will have plants used for medicinals, flavoring, essentials oils, dyes and teas. Another section will display plants of historic value, ranging from collections used in Roman and medieval times to herbs of American Indian tribes and those brought to America by colonial settlers.

There will also be a fragrance garden featuring species roses, the non-hybrid types, and more fragile "sweet" plants, including rosemarys, lemon verbena, and heliotrope.

A special decorative part of the garden will be a 25-by 50-foot herb knot garden. Plant masses will be arranged to look like interwoven chains that will express the traditional elegance of formal gardens of herbs.

The Herb Society was organized in 1935 and its members throughout the U.S. and Canada had wanted for many years to build a herb garden at the National Arboretum.

In the past two years members of the Herb Society have been busy researching display possibilities for the basic design created especially for the National Herb Garden by Sasaki Associates, of Watertown, Mass.

Although the garden will be richly detailed, including changes in elevation and lots of treillage, its generoud dimensions and design will comfortably accommodate large groups of visitors. There will be many places to stop for observation, study, or to sit in the shade. The entire garden will be accessible by wheelchair.

Surrounding the garden will be large shrubs commonly associated with herb gardens-witch hazels, spice bush, bayberry, and Dyer's greenwood as well as small herbal trees such as linden and sassafras.

The National Arboretum which occupies 444 acres, conducts research on trees, shrubs and other plant life. Educational programs will be extended to include herb culture and uses.

"The new garden will help people understand the long history of herbs in the United States and in the world," according to Dr. John Creech, Arboretum director. "Persons from every ethnic group will be able to learn something of their heritage by observing and reading about plants that helped create and sustain their cultures."