What happened to my hydrangea

(Question)

This hydrandrea s grows in a pot. Flowers fried up and leaves turning brown. What ‘s going on with this plant?
Thank you for your help.

(Answer)

Thank you for contacting Toronto Master Gardeners to inquire about your Hydrangea plant.  Your Bigleaf hydrangea (Hydrangea macrophylla) has so many beautiful blooms!   These plants require sun to maximize blooms, but they also need well-draining soil and plenty of water.  We’ve had some very hot, dry days earlier in June.   Hydrangeas need consistently moist soil and don’t do well when the soil dries out.  When blooms turn brown and die off too soon, it’s usually a sign they need more water.

Water your potted Hydrangea macrophylla when the top 1-2 inches of soil feel dry.   During hot, dry weather, you may have to water more than once a day.   If you have space in your pot, add a bit of organic matter or mulch on top of the soil to increase water retention.  It’s interesting to note that the symptoms of under or over watering are similar with Bigleaf hydrangeas – the leaves will wilt, beginning with the leaves closest to the bottom.  Make sure your hydrangea is not sitting in water (empty the tray under your plant after watering or after it rains) as this could cause root rot.   If you suspect your plant has been over watered, remove it from the pot, trim off any dead roots, and repot in new fertile potting soil.

The flowers could also be turning brown if they are exposed to too much hot sun (noon to early afternoon).  If this is the case, move the plant to a location that receives direct sun in the early morning or late afternoon.

Blackening leaves on hydrangea contains a response to a similar question on hydrangeas.

Other useful information:

Hydrangea Fact Sheet

Hydrangea Diseases and Pests

Good luck with your Hydrangea macrophylla!

************************

June 28, 2021