A giant dahlia in the garden

VIRGINIA BEACH 

Lavender flower petals along with red, orange and brown autumn leaves litter the lawn at Mac Houfek's home in Virginia Beach.

The petals are falling from a flower whose blossoms grow on a stalk so tall that they are silhouetted, starlike, against the sky.

Houfek's late-blooming beauty is a giant tree dahlia that looms over the lawn just like a little understory tree. The dahlia is at least 15 feet tall, and its bamboo-like stem is more than 4 inches around.

Some 40 oversized dahlias are blooming up there in the sky. They form somewhat of an umbrella at the end of the stalk, though "trunk" might be a better word for this hefty stem.

Houfek, who enjoys finding and trying unusual flowers and shrubs, purchased the dahlia on a whim about four years ago from Plant Delights Nursery (www.plantdelights.com) in North Carolina. She said the tuber was larger than a big amaryllis bulb.

Each year the dahlia has come back bigger than it was the year before. This year it has outstripped the predictions of the Plant Delights Nursery catalog.

"Dahlia imperialis can reach 30 feet," the catalog reads, "but our garden plants only reach a meager 9 feet in height. The bamboo-looking stalks easily grow to a massive 3 inches in diameter."

Houfek's is truly a giant in comparison.

This year a new stalk is emerging from the ground, and it looks like she eventually could have a grove of giant dahlias in her yard.

The giant tree dahlia is a native of Central America, where the Aztecs were said to have once used the hollow bamboo-like stems to carry water.

Transplanted to Hawaii, they now grow wild there, too. Here in the mid-Atlantic, they will live in zones 7 to 9. In warmer areas where frost doesn't kill the blooms, the giant dahlia will flower all winter. But especially in zone 7, it is vulnerable, the catalog said. The flowers are often hit by killing frost about the time they bloom.

On the other hand, Plant Delights suggests that even if an early frost hits, the giant dahlia is "worth growing just for its stature and texture in the garden... and to fool all your neighbors with its identity."

The plants need full sun and will do really well in a protected spot out of the wind because the stem can be a bit fragile. Houfek's is leaning somewhat, as if running away from Virginia Beach nor'easters.

Dahlias die back in winter, and their stems can be staked without any harm if you stake them in increments starting in spring.

Houfek is so delighted with her giant that she sometimes thinks she should give it to the World of Wonders children's garden at Norfolk Botanical Garden.

With a child's imagination at work, the giant tree dahlia easily could be Jack's beanstalk with lavender flowers.

Mary Reid Barrow, barrow1@cox.net