Spirea Shrubs Are Dying

Question

We have several spirea shrubs that we planted over 20 years ago. This year one by one their leaves began to turn, dry up, die and fall off. Now every shrub is dying. I treated them with Neem oil but it did not help. I do not see black or scorched spots on the stems, so I don’t think it is fire blight. Could it be Verticillium Wilt? We need to know so we don’t infect any future scrubs we replace them with. We trim these shrubs annually so the second pic does show some of that old growth (gray stems) so you don’t get confused between it and this year’s growth.

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Answer 1

To be on the safe side, don't replace these with more spireas, plant a different kind of shrub to lessen the chance of repeating the problem.

It could be verticillium wilt. This article tells you how to determine if it is by examining the inside of the stems. If it isn't wilt, check for spider mites. Prune back the damage and see if that helps. Also you can try a miticide since Neem oil didn't help.

https://www.gardeningknowhow.com/plant-problems/disease/verticillium-wilt-treatment.htm

https://www.gardeningknowhow.com/ornamental/shrubs/spirea/growing-spirea-shrubs.htm

https://www.gardeningknowhow.com/ornamental/shrubs/spirea/pruning-spirea-shrubs.htm

https://www.gardeningknowhow.com/plant-problems/pests/insects/spider-mite-treatment.htm