This section is from the book "Manual Of Gardening", by L. H. Bailey. Also available from Amazon: Manual of Gardening.
The following list of 100 "best hardy perennials" is adapted from a report of the Central Experimental Farm, Ottawa, Ontario. These plants are chosen from over 1000 species and varieties that have been on trial at that place. Those considered to be the best twenty-five for Canada are marked by a dagger (†); and those native to North America by an asterisk (*).
Height, 1 foot; in bloom fourth week of June; flowers, small, pure white, double, and borne in clusters; blooming freely throughout the summer, †
Height, 3 to 4 feet; September; flowers, bluish purple, borne in loose panicles.
Height, 3 to 4 feet; July; flowers, deep blue, borne on a large terminal spike; desirable for the rear of the border.
Height, 6 to 9 inches; first week of May; flowers, large, lemon-yellow, borne singly from the ends of the stems.
Height, 1 to 2 feet; fourth week of June; flowers, medium size, bright crimson, borne singly from the sides and ends of the stems; a very showy plant with silvery foliage, and continues to bloom throughout the summer.
Height 6 to 9 inches; fourth week of April; flowers, large, and deep purple.
Height, 1 to 2 feet; fourth week of June; flowers, large, deep yellow, borne singly on long stems; it continues to bloom profusely throughout the summer; is very showy and valuable for cutting, †
Height, 1 to 1½ feet; third week of May; flowers, medium size, red and yellow.
Height, 3 to 4 feet; fourth week of June; flowers, large, bright lemon-yellow, with long slender spurs; much later than other columbines, †
Height, 1 to 1½ feet; fourth week of May; flowers, large, deep blue with white center and long spurs, †
Height, 1 foot; third week of May; flowers, large, deep blue with white center and short spurs.
Height, 1 foot; second week in May; flowers, large, deep purplish blue with blue and yellow centers; a very desirable early species.
Height 9 to 12 inches; third week of May; flowers, large, deep blue with white center; one of the best.
Height, 6 inches; first week in May; flowers, small, pure white, in clusters.
Height, 9 inches; third week of May; flowers, yellow, borne in clusters with petals spotted with purple. One of the most charming of early flowering plants.
Height, 1½ to 2 feet; third week of July.
Flowers, bright orange, borne in clusters. Very showy.
Height, 9 inches; first week of June; flowers, large, bright purple, borne on long stems from the base of the plant; the earliest flowering of all the asters.
Height, 1 to 11 feet; July to September; flowers, large, deep purple, singly on long stems; very fine.†
Height, 5 to 7 feet; fourth week of August; flowers, bright pink, borne profusely in large terminal clusters ; very showy.
Height, 4 to 5 feet; September; flowers, smaller than the next, pale pink, borne very profusely in large panicles; much later than the next species.
Height, 4 feet; first week of August; flowers, large, white, somewhat resembling asters, and borne very profusely in large panicles.
Height, 6 to 9 inches; first week of July; flowers, medium size, deep blue, borne profusely in loose panicles; continues in bloom throughout the summer. A white variety of this is also good.
Height, 3 feet; first week of July; flowers, large, deep blue, borne on a long spike.
Height, 3 feet; flowers, large, blue, borne in a raceme with long flower stems. There are also white and double varieties which are good.
Height, 4 feet; fourth week of June; flowers, small, pure white, borne profusely in dense clusters. This is a very compact bushy species and desirable for the rear of the border. Clematis Jackmani with large deep purple flowers and Clematis Vitalba with small white flowers, are excellent climbing sorts.
Height, 6 to 9 inches; latter part of May.
Height, 2 to 3 feet; first week of July; flowers, large, yellow, with dark centers and borne singly with long stems.
Height, 2 to 3 feet; fourth week of June; flowers, large, deep yellow, borne singly on long stems, blooming profusely throughout the summer.
Height, 2 feet; fourth week of June; flowers large though slightly smaller than the last, and borne on long stems, blooming throughout the season, †
Height, 1½ feet; first week of July; flowers, pale to bright blue, in large open heads, †
Height, 9 inches; second week of June; flowers, large, white or pink, very sweet scented, and two or three borne on a stem. A variety called Mrs. Simkins is especially desirable, being very double, white and deliciously perfumed, almost equaling a carnation. It blooms the fourth week of June.
Height, 3 feet; second week of May; flowers, heart-shaped, red and white in pendulous racemes.
Height, 1½ to 2 feet; second week of June; flowers, white with an aromatic fragrance, and borne in large terminal racemes. A well-known variety has purple flowers with darker markings.
 
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