There are more than 400 species of willow. The cultivar of willow grown in this part of our garden is 'Nana.' Nana means "small." Mature height of this willow is about 5 feet, much shorter than the more common weeping willow. Branches are red and covered with elongated light green leaves. Willows produce male and female flowers on different plants. Clusters of flowers are called catkins. The catkins from this sype of willow are popular in cut flower arrangements. In nature, willows are found next to ponds and river or stream banks, so adequate water in a garden setting is important.