The characteristic of Salix dasyclados (woolly-stemmed willow) as a source of woody biomass is presented. It is shown that the use of S. dasyclados is limited by its high demand for excessive flow-through moistening. The necessity of studying interclonal and intraclonal reactions S. dasyclados to moisture deficit has been substantiated. The objective is to identify patterns of growth of annual shoots S. dasyclados against the background of early-summer drought. Material: growing annual shoots in the model inbred-clone population. Methods: breeding, comparative morphological. The structure of the seasonal cyclicity of daily growth of annual shoots was studied. It is established that the seasonal dynamics of the growth of shoots is characterized by infradian (multi-day) rhythm. The main types of biological rhythms of the growing shoots (biorhythmotype) have been identified. In the vast majority of cases the shoots of every seedling are of the same biorhythmotype. From 1 to 3 biorhythmotypes differing in reaction to the shortage of rain in early-summer period can appear within the same clone. Invariance and polyvariance of growth trajectories occur in both weak and highly productive clones. It is established that short-term drought and subsequent rains have a modulating effect on the rhythmics of daily growth of shoots. The direct impact of early-summer drought on the development of shoots has not been proven. Highly productive clones, the least affected by short-term early summer drought are recommended to use for breeding Salix dasyclados for drought tolerance.