A dwarf hydrangea is a smaller version of a regular hydrangea, a perennial flowering plant that grows between 1 and 3 feet (0.30 to 0.91 meters) tall. This allows it to be planted in container gardens or confined outdoor areas that don't have the space for a regular bush-sized hydrangea. The types of hydrangeas seen in the regular-size plant, such as mophead and lacecap, are mirrored in similar versions for the dwarf hydrangea and include such popular varieties as mini penny, munchkin, and pink elf. Several versions of the plant have also been bred in Germany and named after European cities, including the Vienna, Berlin, and Paris strains.
The color of the flowers on this species of plant can be altered by changing the pH level of the soil in which it grows, where higher pH levels will tend to produce pink-hued flowers and lower pH levels, the blue- and purple-shaded hues. Red hues can be approached as well, but are really just dark pinks, and white-flowered hydrangeas will not change color regardless of the pH level, though some may sprout a few pink or red blossoms as they age. Many varieties of color combinations are now available for dwarf hydrangeas, with color combinations for flowers including green-pink, white-pink, and green-blue mixtures.
Caring for a dwarf hydrangea involves a bit more attention than many other flowering plants. They require well-watered, fertile soil and partial shade, and grow best where there is sunlight early in the day and shelter from the direct afternoon sun. As they bloom, older flowers must be pruned away to keep the plant vibrant, and they need to be cut back in the fall to avoid growing too large, as they are woody plants that will spread out if given the opportunity. After a fall pruning, the plant will also skip a growing season for blooming and won't produce flowers until the following spring, but this period of rest will encourage it to bloom more vigorously when it does.
Two popular types of dwarf hydrangea that are found for sale in many garden centers are the dwarf hydrangea pia, also known as the pink elf, and Mathilda Gutges variety, also known as the bigleaf hydrangea. The pink elf strain is known as a Hortensia or mophead flower design, which is a spherical-shaped ball of flowers usually a dark pink to red in color. The Mathilda is either a mophead or lacecap flower head design, which is a flatter collection of blossoms. Both strains have the same growing conditions as any other dwarf hydrangea and will change color from pink to blue shades as the pH of the soil drops.