Rhododendron Park in Haaga is Helsinki University's public research garden, planted with rhododendrons and azaleas that thrive in the Finnish climate. Boardwalks lead through the plantings, making it an easy, low-key walk.
The park is at its best in early to mid-June, when the flowers are in bloom. Outside that short season it is still open, but it becomes more of a quiet neighbourhood green space than a destination.