By Redemma
United Kingdom 
Why has my buddleia died?! I thought they were indestructible. I have 2 buddleia bushes in my garden. Both made a promising start in the spring - then stopped growing during the dry patch in April/May. After that was over, one of them burst back into life and is now huge and thriving. The other one made no further growth, and all the little spring leaves it had have shrivelled up and died. The whole thing looks brown and dead. The two bushes are in the same soil, same growing conditions, no weedkiller used nearby. Any suggestions?
21 Jul, 2017
Answers
Also, it could simply be the luck of the draw. Minute, imperceptible differences in soil structure and sun exposure can make critical differences in how well a plant survives drought.
22 Jul, 2017
and the lack of water in April / May wont have helped.
22 Jul, 2017
Mine has died this year too. Don't know why.
22 Jul, 2017
Many thanks for all your helpful comments. Really good to get some informed opinions! I will try compost and better aeration from now on. Thank you.
21 Aug, 2017
Their roots can die back over winter, due to several causes such as waterlogging, lack of aeration in the soil, fungal infections etc.. They appear to grow again in the spring, relying on reserves, then towards the end of June they will at first wilt, and then die. Some varieties, and even individual plants of the same variety, vary hugely in how well they cope with adverse conditions.
The solution is compost - plenty of organic matter in the soil - and aeration by pushing a garden fork into the soil around the trunk to loosen any compaction.
21 Jul, 2017