If they matured you have to report the interest.
See IRS Publication 550 starting on page 7 for Savings Bond Interest. See middle of middle column....
https://www.irs.gov/pub/irs-pdf/p550.pdf
Reporting options for cash method taxpayers. If you use the cash method of reporting income, you can report the interest on series EE, series E, and series I bonds in either of the following ways.
Method 1. Postpone reporting the interest until the earlier of the year you cash or dispose of the bonds or the year in which they mature. (However, see Savings bonds traded , later.)
Note. Series E bonds issued in 1980 matured in 2010. If you have used method 1, you generally must report the interest on these bonds on your 2010 return.
Method 2. Choose to report the increase in redemption value as interest each year.
