Plants wilt when roots are unable to supply sufficient moisture to the stems and leaves. Wilting for short periods of time does not harm plants. Sometimes a plant wilts on a hot day because moisture is evaporating from the leaves faster than the roots can supply it. If there is ample soil moisture, the plant will absorb water in the evening to firm up the stems and leaves. Over a prolonged period, however, drought will cause serious damage, such as yellowing, leaf scorch, browning, leaf drop or stunted growth. Extended periods of drought also inhibit flower formation. Severe heat and water stress when a plant is in bloom may cause scorching or browning of flower buds and blossoms. Plants vary in their ability to tolerate drought and some may die suddenly after extended periods of drought.
Japanese Stewartia drought symptoms