You can try this way out using $root.blah
html
<label ng-click="test($root.blah)">Click</label>
javascript
angular.module('app', [])
.controller('Ctrl', function Ctrl1($scope, $rootScope) {
$rootScope.blah = 'Hello';
$scope.yah = 'World'
})
.directive('myTemplate', function() {
return {
restrict: 'E',
templateUrl: 'my-template.html',
scope: {},
controller: ["$scope", "$rootScope", function($scope, $rootScope) {
console.log($rootScope.blah);
console.log($scope.yah);
$scope.test = function(arg) {
console.log(arg);
}
}]
};
});