Geranium 'Sirak' is a striking, free-flowering hardy geranium, valued for its large violet-blue flowers with prominent dark veining and white centre, produced from late spring into summer. Vigorous and spreading, it forms a broad, leafy mound of dissected green foliage, making it excellent for borders, ground cover, or weaving through other perennials. Fully hardy and easy to grow, it performs well in sun or partial shade.