My agapanthus is mush too, like so many cited here. It's in an exposed part of the garden, in a pot with no protection at all. It's about seven years old and has flowered only once!
@janetfoss Assuming it is still ok, feeding once a week from May until late October helps with flowering. Have you repotted it at all, they do like some fresh compost which will also help. Full sun is necessary too.
I have worked as a Gardener for 24 years. My latest garden is a new build garden on heavy clay.
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