BLOOMING DATES OF SOME SELECTED HARDY 

 PERENNIALS 



By Harold S. Tiffany 

 Assistant Research Professor of Nurseryculture 



Introduction 



A study of the garden value and hardiness of herbaceous perennial material 

 was begun at the Waltham Field Station of the Massachusetts Agricultural 

 Experiment Station in 1931. Evaluation of the material continued until 1936 

 when a recording of the time and duration of the flowering, heights, and color 

 of some 2,000 perennials was begun. These records were continued through 1941 

 for the purpose of securing sufficient data from which to determine the average 

 time and duration of bloom during these five years. From this study are drawn 

 the conclusions which follow. 



Although several very excellent works on this subject have been written, it 

 appears that the broad scope of material included has in itself tended to confuse 

 and baffle the average gardener. Therefore, a limited list of superior selections 

 of tried and proved material has been drawn up for the purpose of a more useful 

 and workable reference. 



The question of what plants are most desirable has as many answers as there 

 are difi^ering and varying landscape developments in which certain plants are 

 more suitable than others. Included are such hardy species and varietal forms 

 as are generally adapted to perennial borders, formal and informal gardens, 

 and a few which are at home in meadow or wild garden plantings. Most of these 

 are readily obtainable in the trade. All the plants are of simple culture. 



It must be kept in mind that blooming dates, particularly of early flowering 

 plants, are very irregular because of climatic conditions bringing either an earl^^ 

 or a late spring. While, in some cases, early flowering plants have differed in 

 their flowering period in certain years by as much as three weeks, this variability 

 gradually decreases as the season progresses and little variation is found after 

 June in fairly normal years. For Cape Cod, average bloom dates would be ad- 

 vanced approximately one week, and for the area north of Boston and the Berk- 

 shires retarded a like period. The lateness of flowering of the early bulbs as given 

 in the lists is due to a mulch covering over winter. Neither very early bud break- 

 ing nor late sparse continuation of bloom has been included, the aim being to give 

 the period of bloom when the flowering is at its height for best garden value. 



It has been the policy to test the plants under average conditions in order to 

 determine which would best survive with ordinary care rather than to work for 

 maximum horticultural excellence. While this attitude has been adopted more 

 because of economic necessity than for other reasons, the plants have thus been 

 given a fairly severe test. The gardens have the benefit of full sun and are not 

 closely protected by hedges or windbreaks. 



