Sentence:  Particular care must be taken not to <WSD>overshift</WSD> such kinds as E. tricolor and its varieties, retorta, Hartnellii, &c. During their progress in growth, attention must be given to train and form the plants as may be desired. 
Meaning of the word marked with <WSD> tags:  (horticulture) To replant or repot too soon or too often.