Hibiscus Syriacus. - The Althea is a well-known ornamental shrub, of easy cultivation; but a little tender in some situations, particularly the double white variety. They grow freely from cuttings, from which the double varieties are multiplied; or very easily from seed, for single varieties. We think some of the single varieties are equally handsome as the double, and generally more. hardy. There is the double white, red, blue and white, with stripes, or blotches, and others.