Combine 2 Dates into 1

In my select statement I have 2 dates and I tried using a (+ '-' +) to add the 2 fields together but it kept giving me this error   (The conversion of a char data type to a datetime data type resulted in an out-of-range datetime value.)  The following is my sql code, what I am trying to do is put the dates together and try to format them as 26-30 june 2008, right now they would show up as 26-june-2008 and 30-june-2008 in my labels on aspx page.  Is this possible or not????  Thanks

select      s.sidstrName_IND,
      s.sidstrST_ADDR,
      s.sidstrADDR_CITY,
      s.sidstrSTATES_US,
      s.sidstrZIP_CODE,
      s.sidstrGR_ABBR_CODE,
                     s.sidstrPAY_GR,
      cast(datediff(year, siddatPEBD, getdate()) as varchar(20)) as PGYrs,
      count(p.intAssignedPersonnelID),
      min(p.dtattendance) + '-' + max(p.dtattendance) as EDate    (Problem Area ??????)
from      cms.dbo.tblSIDPERS as s INNER JOIN
      tblAssignedPersonnel as p on s.sidstrSSN_SM = p.strSSN
where      p.bitPresent = 1 And
                     p.intDrillStatus = 2 And
      p.dtPayProcessed Is Not Null and
      p.dtPaid Is null and
      p.intUICID in (select intUICID from tblUIC where intTaskForceID = '13' and strUIC = 'PU3B1') and
                     p.strSSN = '474968040'
group by      s.sidstrName_IND, s.sidstrST_ADDR, s.sidstrADDR_CITY, s.sidstrSTATES_US, s.sidstrZIP_CODE,  s.sidstrGR_ABBR_CODE, s.sidstrPAY_GR, cast(datediff(year, siddatPEBD, getdate()) as varchar(20))