I have had agapanthus in my garden for about 3 years. They bloomed the first year but not since. They look fine, and I fertilize them and they're propagating very nicely, BUT NO FLOWERS. What else can I do to get them to bloom? Thanks.
The Agapanthus should be divided every 3rd year to keep it blooming.
Fertilize in the early spring with a balanced fertilizer, like 10-10-10.
Apply half that amount again mid summer.
Make sure the fertilizer is balanced and not too high of nitrogen. Too much nitrogen will cause lots of green leaves and no flowers.
Here are some articles to help you.