Hydrangea plant named `Frau Katsuko`

This invention relates to a new and distinct cultivar of Hydrangea macrophylla (Thunb.) named `Frau Katsuko` which originated as a seedling from the inventor\'s controlled hybridization of the Hydrangea macrophylla cultivars `Madam Blumkock` and `Silver-Edge` and is distinguished from its parents by the combination of its pigmentation pattern in its sepals which is predominently colored with deep, irregular, white edges; its deeply serrated, ruffled edges; and its dense inflorescence that does not require staking for support. Pigmentation is darkest at base of sepal, fading slightly as it progresses along the length and width of the sepal, and then turns white as far as 5 mm from edge. The sepals of `Madam Blumkock` are uniformy pigmented one color, while the sepals of `Silver-Edge` are also uniformly pigmented except the sepal edges are white. The new variety `Frau Katsuko` further possesses the favorable characteristics of a compact growth habit, long lasting large flowers and it is easily forced in a greenhouse for flowering in the spring without growth regulation.