Willow 
To dream of a willow tree symbolizes sadness and mourning.
Wind
To dream of the wind blowing represents your life force, vigor, and energy. It is a reflection of any changes in your waking life. To see gusty or strong winds is a representation of trouble and inner turmoil. There is much anxiety in your waking life.
Yucca
To dream of the yucca tree indicates that you may be nervous about an impending situation and cautions against feeding this anxiety with foods high in acid like coffee, chocolate, or meat. Moderation is the key at this time.
To dream of yucca flowers may be a reminder from spirit to ensure your diet is replete in vitamins (especially thiamine or vitamin B1, riboflavin or vitamin B, calcium, and iron).
Many yucca trees in a dream signifies an ingenious money-saving idea.
Zinnias
To dream of zinnias indicates friendship, joy, and laughter. It further symbolizes the pleasures of summer.