We recently had a visit from a customer, puzzled by their agapanthus flower head, with its slightly deformed flower buds and its failure to open into full bloom. This is a problem which we have had little experience of in the past, and were slightly puzzled by ourselves.

More frequently we hear reports of agapanthus growing lush foliage at the expense of flowers – a problem commonly caused by poor watering after flowering, over-dividing, over-potting, or on the contrary, letting it become excessively pot-bound. But this problem was less familiar, so we turned to the wonderful world wide web for answers!…And the ‘go-to’ resource for gardeners, the RHS, came up trumps…

Agapanthus gall midge is a new species of fly affecting Agapanthus that can cause buds to become deformed and discoloured and fail to flower. It was first noticed in the UK in 2014 but may have been present for several years.

Agapanthus gall midge is a tiny fly that lays eggs on the developing flower buds of Agapanthus. The feeding activities of the larvae inside the buds cause abnormal bud development and infested buds can fail to open”.

It seemed very possible that this gall midge could responsible for the troubled agapanthus and we passed on this information to the customer in case they wanted to investigate further/take action. On returning home, and under close inspection, the customer was actually able to see the midge-larvae in some of his flower buds, and is now taking action to manage the problem – by removing all contaminated heads and applying (and re-applying) ‘bug-killer’ to try and eradicate all larvae. Fingers crossed it works.

As a ‘new’ disease, highlighted above as only first being noticed in 2014, we thought it would be a useful one to share with you all, particularly agapanthus lovers and owners, in case something similar ever shows itself on your plants.

Research is ongoing – there is a lot more to learn about the disease, its effects and how it should be controlled, but it’s certainly one to keep track of in coming years.