Xylem & Phloem

Keep in mind that many professional hydrangea growers never cut back the plants at all, preferring to leave dead flowerheads on the plant to provide winter interest and food for hungry, seed-loving birds.

Hydrangea.com has a page dedicated to correct hydrangea pruning here.  

There are, however, new exceptions to his rule. New varieties are being developed every year to satiate the public's appetite for no-fuss, repeat blooming hydrangeas. In my landscape, I have a mix of traditional and care-free varieties.

In my front border, I have planted a row of Blushing Bride hydrangeas. This a gorgeous variety with blooms that are pure white, maturing to a blush pink or blue, depending upon your soil acidity. Blushing Bride is part of the Endless Summer series from Bailey Nurseries. Unlike traditional varieties, Blushing Bride blooms repeatedly through the spring and summer. The plant also bloom on new and old wood alike.

2. Protect hydrangeas in early spring after buds begin to emerge but spring frosts still threaten. As mentioned above, hydrangea flower buds develop on the previous year's growth in early spring. Many times, bud emergence is well before the last frost date for an area. (I had some frost damage to mine this year.)

To ensure that you get the most bang for your buck in terms of blossoms, take care to protect your hydrangea plants during the final weeks leading up to spring when sudden frosts are still likely.

UPDATE: Hydrangea Craft at MarthaStewart.com: Check it out!