The number of Americans buying new homes dropped in March to the slowest pace in seven months, the government said Wednesday, in a sign that real estate’s spring buying season is off to a weak start. The Commerce Department said that sales of new homes declined 14.5 percent last month to a seasonally adjusted annual rate of 384,000, marking the second straight monthly decline and the lowest rate since July 2013. Sales plunged in the Midwest, South, and West in March, but rebounded in the Northeast, where snowstorms in previous months curtailed purchases. New home sales have fallen 13.3 percent over the past 12 months. “Our core view is that the housing market has stalled and won’t contribute” to overall economic growth this year, the Associated Press quoted Ian Shepherdson, chief economist at Pantheon Macroeconomics, as saying. Rising home prices have caused some buyers to back off at the lower end of the market, while new-home buyers at the top continue to buy. Because of this, median sales prices rose 12.6 percent during the past month to $290,000.