Snowy hydrangea flowers, just two, topped thirsty stems in a vase. Softly mounded, they needed no further design.

“Oh!” said Helen. “They look just like whipped cream!”

Hydrangeas are hard to miss in our summer landscapes. Discovered in this country in the early 1700s, explorers found and brought back — many other varieties from Asia, mostly from China and Japan. (Still more grow in South America; have any been cultivated commercially in our climate?)

The first native hydrangea was found and grown in 1736 as a curiosity. Ten years later, it bloomed. It was used in some gardens just for variety.

In the 19th century, when Asiatic species became available, gardeners grew interested in learning more about all kinds of hydrangeas. Botanists began the long history of hybridizing them for different purposes, all to do with beauty.

In our area, Hydrangea arborescens, such as “Hills of Snow” and “Annabelle” have done well. Priscilla’s shaded Rockland house was surrounded by “Annabelle,” which grew so eagerly that the shrubs crept into the lawn when nobody was looking, and had to be curbed. The lavish snowball-blooms helped to lighten that dark area.

Normally, however, hydrangeas in our part of Maine like a bit more sun. Wherever they are, they crave water — as the first syllables of their Latin name (“hydra”) would indicate.

Outside our dining room windows are hedges of an unknown hydrangea. In 13 years, they have bloomed once-and-a-fraction. They have been pruned in winter, in early spring, even in fall. Right now, the hedges of lush, dark leaves are interspersed with low, dead twigs, left from one of those prunings.

This is, I learned, a good time to root hydrangeas, using shoots from the sides, not the tips. I shall try this and(if the cuttings last through the winter on an unheated porch), try any new plantlets — potted — outdoors in different areas of light and shadow.

There’s so much to know about hydrangeas that I’ve barely begun to describe them. Questions? Tell me, care of this newspaper.