How annoying that the pond plants aren't growing properly! This can have several causes. Below are the most common causes. 

Fountain, filter or pump present
Pond plants don't grow well if the plants are placed too close to a pump, filter or fountain. The plants need calm water to grow. You can place the plants in a different spot in the pond or turn down the pump, filter or fountain. 
 
Koi carp / large fish
Koi carps or other large fish often eat the plants or turn everything in the pond upside down. 
Therefore, wait before adding fish until the plants have grown well. Do you already have fish in the pond? Then select plants the fish don't find attractive. Or, if possible, create different zones in your pond that the fish cannot reach. 
 
Too deep or shallow
Pond plants have a minimum and maximum placement depth. If the plants are too shallow, it becomes too hot for the plants. The water boils, and the plants don't grow. When the plants are placed too deep, they don't get enough light or heat. It is therefore very important to place the plants at the specified depths. 
 
If one of these causes, is the reason why the plants don't grow well, the 100% growth and bloom guarantee doesn't apply. Do you still have a question? Please contact us via this form.