$ perl 
use strict;
use warnings;
use Data::Dumper; 

my $string="1:one;2:two;3:three";
my %hash;

my @list1 = split /;/, $string;
foreach my $item(@list1) {
  my ($i,$j)= split(/:/, $item);
  $hash{$i} = $j;
}
print Dumper \%hash; 
__END__
$VAR1 = {
          '1' => 'one',
          '3' => 'three',
          '2' => 'two'
        };
$