Gardeners love hydrangeas because they're beautiful--with big, soft dollops of blooms in pink, white, chartreuse, purple and blue. Hydrangeas add gauzy yet powerful color to a garden for weeks, starting with bigleaf types that bloom in June, extending through winter if flowers are left to dry on the limbs.
Hydrangeas are more popular today than ever, thanks in part to the recent development of new kinds, especially those that rebloom on new and old stems. "Today, we're seeing many new varieties, and I see no indication of this slowing down," says Jonathan Pedersen, brand and business development manager for Bailey Nurseries near Saint Paul.
Hydrangeas are generally worry-free, though some types need periodic pruning. "Here's a group of plants that don't have insect or disease problems, so for the little care you give them, the rewards are great," says Ed Hasselkus, horticulture professor emeritus at the University of Wisconsin-Madison.
It's important to choose a hydrangea that's appropriate for your Zone and landscape. The next slides show four main types of hydrangeas: bigleaf (H. macrophylla), panicle (H. paniculata), smooth (H. arborescens) and oakleaf (H. quercifolia).
Bigleaf (H. macrophylla) hydrangeas, which include varieties that can be pink or blue depending on soil conditions, are a longtime home garden favorite. And they're even better today: Many new types bloom on new and old growth, not just on last year's stems.
Among the new bigleaf hydrangeas are Endless Summer, released in 2003, and Forever & Ever, released in 2005. "They're a very romantic flower in a softer, shadier part of the garden," says Linda Guy, new products director for Novalis, a national plant company that offers several bigleaf hydrangeas.
Type of flowers: Early summer flowers bloom in white, blue, purple or pink, depending on variety and soil. Two flower head shapes: rounded mophead and flat lacecap.
Where to plant: Grow in partial sun to shade with 1-2 inches of water per week. For blue flowers, add aluminum sulfate to soil, following package directions.
What to watch for: Can be vulnerable to late spring frosts. Overfertilizing, overwatering and a lack of sun can delay or prevent blooms.
Recommended types: Try mopheads 'Lemon Daddy' and Cityline series, plus rebloomers Endless Summer, Blushing Bride, Forever & Ever series, Let's Dance series and Mini Penny. Try lacecap Light-O-Day and rebloomers Let's Dance Starlight and Twist-n-Shout.
Zone: Generally as far north as Zone 5 or 6; some hardy in Zone 4 with winter protection.
Panicle (H. paniculata) hydrangeas are especially recommended for the Midwest because of their cold tolerance. Panicle hydrangeas bloom best in full sun, and most are hardy to Zone 3. Because of their larger size (6-8 feet tall and wide) and vase shape, panicle hydrangeas often appear in hedges, borders or as a garden's focal point.
"It's hard to beat a paniculata for the Midwest. They're just plain beautiful plants," says Tim Wood, horticulturist and product manager for Proven Winners ColorChoice plant company in Grand Haven, Michigan.
Type of flowers: Flowers open white or chartreuse in midsummer, aging to pink or tan.
Where to plant: Grow in full sun.
Recommended types: Try: 'Limelight', Pinky Winky, 'Little Lamb', Quick Fire and 'Tardiva'.
Zone: Zone 3.
Smooth hydrangeas (H. arborescens) also perform well in the Midwest. The most popular, 'Annabelle', was found in 1910 along a wooded trail near Anna, Illinois.
Annabelle is a reliable and profuse bloomer, although its flower heads can get so large--up to a foot across--that they droop. You can prop up the plants with a short wire fence or other support.
Type of flowers: White, round flower heads are the typical bloom, although a new variety scheduled to be introduced in 2010, 'Invincibelle Spirit', is pink and is a rebloomer.
Where to plant: Grow in sun to part shade.
Recommended types: Try: 'Annabelle', 'Hayes Starburst', White Dome.
Zone: Zone 4 ('Invincibelle Spirit' is hardy to Zone 3).
Oakleaf hydrangeas (H. quercifolia) grow panicle flowers on rangy stems with attractive, peeling bark. They're native to the United States and super-easy to grow in warm climates, but not hardy enough for much of the Midwest. If you live in Zone 5, an oakleaf is a good low-care option.
Type of flowers: White flowers turn pink or brown in fall. Leaves go red.
Where to plant: Grow in sun to shade.
Recommended types: Try 'Sikes Dwarf', 'Little Honey', 'Snowflake', 'Vaughn's Lillie'.
Zone: Zone 5.
Cut hydrangeas will sometimes wilt almost as soon as you bring them in from the garden. Either the sticky sap in the stem or trapped air bubbles can form a barrier that prevents the flower from taking up water.
Some techniques that will help prolong your blooms:
-- Cut flowers in morning or evening, when it's cooler.
-- Bring a container outside and place stems in water as soon as you cut them.
-- Give stems a quick hot-water bath. Boil water and pour it into a container. Hold the bottom few inches of your hydrangea stem in the hot water for 30 seconds, then transfer to a vase with room-temperature water.
Click here  to read more about hydrangeas in the Plant Encyclopedia of our sister publication, Better Homes and Gardens.