Malone, the 72-year-old chairman of Liberty Global Inc., paid about 8 million euros ($10 million) for the neo-Gothic Humewood Castle in Ireland after it captured “my wife’s fancy,” Malone said in an interview this month.

“We call it our green banana project because at our age, you don’t buy green bananas,” Malone said. “It’s going to take a number of years to get it restored.”

Malone is among a growing number of Americans returning to their Irish roots and scooping up mansions and castles after the worst real-estate crash in western Europe. Overseas buyers accounted for nine of the 10 biggest sales of Irish country mansions last year, with 40 percent of those from the U.S., according to Dublin-based estate agency Sherry FitzGerald Group.

“Experience in 2013 suggests this trend is continuing if not increasing, with the U.S. buyer being crucial,” said David Ashmore, head of country home sales at Sherry FitzGerald. “There’s a significant international dimension to country house-selling campaigns today.”

Haughey’s Home

Sherry FitzGerald and Christie’s International Real Estate, on behalf of the receiver, are restarting efforts to sell the Dublin home of deceased Irish Prime Minister Charles Haughey. The house, Abbeville, and the rest of the 250-acre (101-hectare) estate is being offered for 5.5 million euros, Ashmore said.

The property was put on the market last year for 7.5 million euros by a different property broker, without being sold. The Irish Times reported at the time that the estate was sold in 2003 for 45 million euros.

An overseas purchaser last month bought Ardbraccan, an 18th-century mansion set in 120 acres of land with an asking price of 4.9 million euros, according to Savills Plc, which handled the sale. Charles Noell, founder of Baltimore-based private-equity firm JMI Equity, bought the property northwest of Dublin, the Irish Times said, without citing anyone.

Noell didn’t reply to two e-mail requests for comment or a telephone call to his office.

Irish Slice

The chance to buy a slice of Irish countryside comes courtesy of the country’s property developers, many of which went bust when the market crashed. They, along with local business executives, were once the main buyers of the biggest homes, according to Harriet Grant, head of country-house sales at the Irish unit of broker Savills.

“In the boom times, the market was purely domestic,” she said.

Some Irish country mansions are now selling for about a third of 2007 levels, when the real estate market peaked, said Tancred Lidbury, head of European sales at Christie’s International Real Estate in London.

“There is a market, but it’s at this level,” Lidbury said. “It’s disappointing for people out there whose house may have been worth 20 million euros five, six years ago and may only be worth 6 million or 7 million euros now.”

Humewood Castle

Malone bought Humewood Castle in November from an Irish developer whose plan to turn it into a resort were “demolished” after the real estate bubble burst in 2008, he said. Humewood, which includes over 420 acres of land, was sold in 2006 for 25 million euros, according to the Irish Times, the Dublin-based newspaper.

The castle, about a 60-minute drive south of Dublin, was built in the 1860s and includes 15 bedrooms, a ballroom, billiards room and music room with fitted bar.

“Unemployment is so high in Ireland we thought it was a good time to undertake something that would put a lot of people to work,” Malone said. He bought the property as “a nice private kind of family, friends get-away place.”

Liberty Global is in the process of buying U.K. cable television provider Virgin Media Inc. for $16 billion. The deal, approved by the European Union last month, will give the company a bigger share of the continent’s biggest market.

“We are going to be travelling for business purposes more frequently to Europe,” Malone said. He hopes to visit the castle about four times a year.

Roots Traced

Malone traces his roots back to an Irishman of the same name who moved to Pennsylvania in the 1830s. About 34.5 million U.S. residents claimed Irish ancestry in 2011, according to the U.S. Census Bureau.

Irish-American Jim Thompson, founder of closely held moving company Crown Worldwide Group, bought a country home with about 500 acres of land outside Stradbally in southeast Ireland last year for about 7 million euros.

“As I look my window at the river, the grass and the trees, it’s a nice place to be,” Thompson said. “I was mesmerized.”

Thompson, whose ancestors left Ireland in the mid-1850s, is renovating five other houses on the estate in addition to the main house. While his ancestors who worked in copper mines in the area may never have stepped foot on the property, Thompson said he feels a responsibility to bring the place back to its former glory.

“There are 10 bedrooms,” said Thompson. “Even the bathrooms are quite huge: you could have a small party in the bathrooms if you wanted.”

Humewood buyer Malone said the castle has been renovated to a level where he can now stay at the place. Even the Irish weather isn’t going to put him off, he said.

“I am enjoying my seniority and senility I guess,” Malone said, laughing. “We are from the arid west here in Colorado and so it’s kind of nice to see green, even if it comes with a little liquid snow.”