A new high-quality doublefile viburnum, "Shasta," has been introduced by the National Arboretum, and is now being grown in many wholesale nurseries for sale to the public.

In addition to its profusion of white flowers in May, it has landscape merit in all seasons of the year, such as distinctive horizontal branching, green-pleated leaves that are attractive throughout the summer and dull but appealing purplish-red in autumn, and scarlet-red berries in midsummer.

Shasta resulted from the hybridization in 1954 of a select Viburnum plicatum f. tomentosum plant growing on the Cornell University campus and V. plicatum f. tomentosum 'Mariesii.' From the abundant seedling population, a superior one was selected in 1968 for propagation and evaluation.

After outstanding performances in trial plantings, additional plants were distributed for stock increase in 1975.

The plant will thrive under diverse climatic and soil conditions, grows well in many exposures, but does best in sun or in light shade with moderate moisture. Since indiscriminate pruning destroys the horizontal branch lines, the plant should be allowed to develop naturally.

Plants are easily propagated by soft-wood cuttings under mist; small plants frequently will bloom the first season, but it is not until the third year that flowering and fruiting are heavy.

The original plant of Shasta in 12 years has attained a height of about seven feet and a breadth of about 10 feet.

The mimosa, Albizzia julibrissin, in full bloom is an attractive small tree with fern-like leaves and slightly fragrant light-pink to rosy-red flowers.

There are thousands of them growing in this area. Many have been killed by a disease, Fusarium oxysporum perniciousum, for which there is no cure. Now, the Coastal Plain Agricultural Experiment Station, Tifton, Ga., and the USDA Science and Education Administration, announce the introduction of a new variety, "Union," that is resistant to the disease.

Union is a selection from seed obtained by the Forest Service in 1951, through self-pollination of a resistant tree. The seedling survived inoculation with the disease in the seed flat. In 1960 plantings were made of the selection in an area at Tifton to which inoculum from different sources were applied yearly from 1960 to 1965.

No evidence of the disease has been seen on plants grown at Tifton, the National Arboretum, Mobile, Ala., or Wachapreague, Va. since 1972.

The original tree of Union has a crown spread of approximately 50 feet and a height of about 26 feet. Individual flower clusters are approximately 12 inches wide. Flower color is light red, yellow and white. The tree has proven cold hardy in the National Arboretum since 1970, weathering the severe winters of 1976-77 and 1977-78.

Plants will be available to the nursery industry for sale to the public Oct. 15, 1979 from Gulf Stream Nursery, Wachapreague, and in limited quantity from Science and Education Administration, Agricultural Research, Tifton. CAPTION: Picture, The new viburnum, "Shasta": A profusion of white flowers that bloom in May.