Not exactly answering your question maybe…
…but since your time string is perfect for pulling the time comparison into the domain of string comparison…

use strict;
use warnings;

chomp(my @directories_time_tagged = <DATA>);

for my $directory_name ( @directories_time_tagged ) {
  next unless $directory_name =~ /(\d\d\d\d_\d\d_\d\d_\d\d)/;  # Year_
+month_day_hour
  my $date_time = $1;
  my ($year, $month, $day, $hour) = split /_/, $date_time;

  my ($y_now, $m_now, $d_now, $h_now) = (localtime)[5,4,3,2];

  my $now = sprintf('%d_%02d_%02d_%02d', $y_now+1900, $m_now+1, $d_now
+, $h_now);

  if ($date_time le $now ) {  # If the date has been passed
    print "\nconditions have been met for $directory_name\n";
  }
}

__DATA__
foo_2006_03_02_14_verzeichnis
bar_2007_05_02_02_directory
baz_2007_05_03_22_dossier
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