Hi there,
I have about ten big leaf hydrangeas (let’s dance blue jangles variety). They bloom on old and new wood and were covered this winter for protection. We are just east of Toronto and they are in an east facing yard with full morning sun.
This spring they came back completely healthy and have been full of buds and then about two weeks ago they started wilting and dying. They are watered regularly and one is potted and has the same issue. The leaves and flower buds look great and then each stem wilts and dies back (does not brown). We dug one up that has died almost entirely and the root system is healthy with no rot or sign of insects. Any help with what may be going on is hugely appreciated.
Thank you for consulting Toronto Master Gardeners about your wilting hydrangea stems .
Given that you report no change of soil, routine , watering schedule , sun exposure and that roots are healthy ,you can see no rot , no insects ( any chance of fertilizer or pesticide use ? ) the wilting is a puzzle until we remember the dangerously high temperatures of mid June . Hydrangeas use a lot of water so my guess is that the sudden hot day temperatures that did not cool down at night , did not allow your plants to recover their day time water loss. You could try watering deeply right down to the roots to see if this helps and perhaps put a few handfuls of organic matter on the soil /pot surface to improve moisture retention .
Do you have schedules that let you water when the soil is dry(not on a fixed schedule)? While time consuming, it does mean that plants don’t get overwatered after rain or under watered during a drought and it gives you more time with in your garden.
In case other new symptoms appear , here is a link to an informative site about other things that can go wrong with hydrangeas .
https://homegarden.cahnr.uconn.edu/factsheets/hydrangea-diseases-and-pests/
I hope your plants recover .
Thank you for consulting us .
July 3, 2024