NEW YORK (CNNMoney.com) - Are there really jobs that Americans just won't do?

The debate is anything but academic to millions of small businesses, across the country, that depend on migrant labor. Immigration reforms under consideration in Congress could put guest worker programs in jeopardy and force business owners to find workers who are citizens.

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Pete Haran, vice president of New Jersey-based landscaper Lipinski Landscaping, has relied on the guest worker program, which grants temporary work visas, for the past 10 years. He brings in hundreds of workers from Mexico and Poland to fill jobs that he says American workers don't want.

As part of the guest worker program, known as H2B, Lipinski must advertise jobs paying $8.75 to $14 an hour to attract domestic workers but after "18 days of advertising, we got one phone call this year," he said.

Haran, like other small business owners dependent on guest workers, is worried what would happen if Congress repealed those programs.

"Before the H2B program, I was spending thousands on ads trying to hire people," said Haran. "College students don't even want to do that kind of work, and I kind of blame the parents," Haran said.

"Even Clinton wanted every student to go to college and now there are less people to fill the low-end jobs;" jobs that typically get filled by younger workers with less education, he added.

Most agree that current immigration policies are largely unresponsive to the labor needs of the U.S. economy. As the U.S. work force ages and is better educated, there is a growing gap in industries that rely on low-skilled labor.

"The situation on the ground looks the way it does because we've had a broken immigration system for years," said Craig Regelbrugge, senior director of government relations at the American Nursery & Landscape Association.

"We estimate right now that 70 percent of the labor force working in this industry lacks proper immigration status. The idea that we can work without these people is just crazy," Regelbrugge said, referring to the immigration debate in Congress.

There are currently some 11.5 to 12 million unauthorized migrants living in the U.S., which account for more than 5 percent of the labor force, according to a study by the Pew Hispanic Center.

Those workers are mostly in blue-collar service jobs such as farming, cleaning, construction and food preparation, according to the study.

"To say the current program falls short is an understatement. The current system is not serving anyone's purposes except for smugglers and unscrupulous employers," according to John Gay, vice president for government affairs at the National Restaurant Association, which represents restaurant chains.

"We don't have people here to do the jobs that need to be done," said Laura Reiff, co-chair of the Essential Worker Immigration Coalition and co-chair of the Business Immigration Group at Greenberg Traurig, one of the nation's largest law firms.

President Bush told CNN that he hopes there will be "comprehensive immigration reform...that recognizes that there are hard-working people here doing jobs that Americans won't do." The president has been pushing Congress to pass legislation that includes a temporary guest-worker provision for noncitizens.

But not everybody agrees that there are jobs that Americans won't do.

"I do think in many respects that argument is a little overblown," said Jon Dougherty, a policy analyst with Freedom Alliance, a conservative nonprofit foundation. He argues that the problem, instead, is that the influx of immigrants has depressed wages and made it too difficult for many Americans to compete with undocumented workers willing to work for less pay.

"It bothers me that people will pay immigrants below-market wages because it undercuts American employment and it exploits immigrants," Dougherty said. "Americans will not do jobs they cannot afford to do," he argues, because "the wages have been depressed so much, it's not really worth it."

But, he believes, "for the right money people will work at any job."

House Republicans passed a bill in December that scrapped the guest-worker program, omitted any way for illegal immigrants to work their way become citizens, and made it a felony to come across the border illegally or to help illegal immigrants. The House bill also authorized construction of 700 miles of security fencing along the U.S.-Mexico border.

The House bill contains neither of the provisions in the stalled Senate legislation that have divided Republicans - the guest-worker program and a process allowing illegal immigrants to pursue legal status to stay in the country and obtain citizenship.

Judiciary Committee chairman Arlen Specter has vowed to turn his panel's attention to moving a bill back to the full Senate quickly.

If the Senate manages to pass a bill, a joint committee of members of the House and Senate would have to reach a compromise.

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Small business owners sweating over immigration debate. More here.