Somehow the \ in this case doesn't do what I need.

Correct. The following:

takes a reference of every item in the list, without flattening it first.

See the following as an example:

use Data::Dumper;

my $scalar = 'string';
my @array = ( 1,2,3 );
my %hash = ( a => 1, b => 2 );
print Dumper \( $scalar, @array, %hash );
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This is also a useful trick for getting a reference to a scalar when your editor's syntax coloring (eg, BBEdit) thinks you're escaping a quote: