KAILUA — The majestic royal palm trees that line the Ryan residence on well-traveled Ulumanu Drive have long been admired by residents.

But the Ryans can't keep all 18 trees, which were planted on the 7,500-square-foot property more than 20 years ago.

The maintenance is too much for them, and one of their neighbors is allergic to the flowers produced by the trees.

So the family is offering 12 of these mature, 30-foot royal palms to any church, school, government building or nonprofit organization to use for landscaping at no charge.

Private or commercial businesses can purchase the trees — which are valued up to $1,000 each, according to the family — for a nominal fee.

"We're trying to avoid killing them," said Pohai Ryan, 45, mother of three, walking around her backyard on Monday. "It's really a bummer because I love trees."

Last year the Ryans approached the city and state to see if either was interested in taking the royal palms for landscaping purposes.

While the city declined, the state Department of Transportation was interested in replanting the royal palms along Kailua Road, which is being realigned and landscaped in the final phase of the state's $5.8 million rockfall mitigation project.

But the Board of Water Supply pointed to a water main line that runs about 3 feet below the roadway in that area.

The deep roots of the royal palms could have damaged the water main and make it difficult for crews to do maintenance work.

So the Department of Transportation decided to plant loulu palms, which are smaller and have shallower roots, on that upper portion of Kailua Road, leaving the Ryans to find someone else to take their royal palm trees.

The loulu palms will be added along Kailua Road starting in a couple of months.

"We really wanted to use the trees," DOT spokesman Scott Ishikawa said about the royal palms, which the Ryans were going to donate to the state for free. "But because of the location of the water main, it just wasn't feasible ... It was just unfortunate."

Royal palms are a stately, slow-growing type of palm tree that aren't very common in residential areas in Hawai'i anymore.

They can grow up to 75 feet tall and require plenty of water and sun.

Ryan, who was born and raised in the Kawela area of Moloka'i, doesn't want to uproot and dispose of these trees.

But if she can't find anyone to take them soon, she may have to resort to that — in her opinion — drastic action.

She's planning to keep the six royal palms facing Ulumanu Drive and replace the others with different, easier-to-maintain trees or plants.

"I'd prefer to see them in Kailua somewhere, but at this point, I don't care where they go," Ryan said. "We just don't want to kill them."

Reach Catherine E. Toth at ctoth@honoluluadvertiser.com.