|'Mariesii' is a lacecap type of hydrangea that grows 4 to 5 feet tall. The flowers are usually pink to mauve except under the most acid soil conditions when they may be a pale blue. This deciduous, rounded shrub has ovate, toothed green leaves to 8inches long. Enormous flower clusters to 8 across bloom in summer and early fall. Lacecaps have small fertile flowers in the center of the cluster, surrounded by larger, four-petaled sterile flowers. Hortensias, also known as Mophead Hydrangeas, have clusters made up of only large sterile flowers. Pink or blue flower color is determined by soil pH. White varieties are not affected by soil pH. Hydrangeas do best in moist, well drained, moderatly fertile soil that is rich in humus. Protection from winter winds and extreme cold is best. Cultivars of Hydrangea macrophylla fall into either Lacecaps or either Hortensias. Red to pink flowers occur in alkaline soils and blue to purple flowers in acid soils. Hydrangeas can be forced to change flower color, however, this must be done before bloom begins. To make or maintain blue flowers in alkaline soils, treat with aluminum sulfate. To make or keep pink flowers in acid soil, add lime.