Through her works, Yastreb generated aesthetic ideas embraced and developed by the Odesa nonconformists, who opposed socialist realism and resisted the rigid demands of official art of that period. She became an informal leader for artists in search of their own creative path and identity. Many of the ideas and professional techniques formulated and realized by Yastreb became the foundation of the artistic program of the group Mamаi, which continues to hold an important place in contemporary Ukrainian art.
The central theme of her work was the image, appearance, and grandeur of womanhood — both in its philosophical and aesthetic dimensions — and now these works are part of the Golden Fund of Art of Ukraine. Her avant-garde paintings at once evoke associations with naive art and with the masters of the Early Renaissance, reflecting the richness and diversity of traditions she drew on.
Yastreb often used pure colors in her paintings, yet it was through her use of white that she achieved the greatest resonance. In her works, white symbolized life and affirmation, the tension of the sun and heat, the purity of thought and the light of space — but never merely a background. Color, rhythm, figure — everything carried meaning and together created essence. The message was the triumph of life. Her art radiated astonishing vitality and joy of existence despite her severe illness. Creativity overcame pain and gave no chance to despair. Yastreb is known as the White Angel of Nonconformism.