Can I cut back the long stems now?

It is best to wait until after the hydrangea has finished flowering. Cutting now might remove the buds for next year.

Will these stems ever get thicker?

Existing stems will harden over time, but they likely will not thicken significantly. Pruning them back later will encourage new, stronger growth.

Bigleaf Hydrangea: leggy growth, causes and fixes

Check these first

Observe how many hours of direct sunlight the plant receives each day.
Check if the plant is leaning toward a window or a shaded area.
Inspect the stems to see if they are soft and weak or just long.

Likely causes

Insufficient Light
Most likely
How to tell: The stems grow long and thin with large gaps between the leaves as the plant stretches toward a light source. You might also notice the plant leaning heavily to one side.
What to do: Move your hydrangea to a spot that receives bright, indirect light, ideally with morning sun and afternoon shade. If you are growing it indoors, place it directly in a sunny window or use a grow light for 10 to 12 hours a day.
Excessive Nitrogen Fertilizer
Possible
How to tell: The plant produces a lot of lush, soft green growth that cannot support its own weight. This often happens after using a high nitrogen fertilizer meant for lawns or leafy vegetables.
What to do: Stop using high nitrogen fertilizers immediately. Switch to a balanced, slow release fertilizer designed for flowering shrubs to encourage sturdier growth.

Find out what's wrong with your bigleaf hydrangea

The list above covers the usual causes. Pocket Botanist looks at a photo of your actual plant and tells you the likely cause, how serious it is, and what to try first. Identification and a health check are free.

When to worry

It is not a medical emergency, but it will affect the plant's ability to produce large blooms. If the stems are so weak they are snapping, you should prune them back after the flowering season ends.

Stopping it coming back

Provide consistent, bright light and avoid overfeeding with nitrogen heavy products. Proper pruning in late summer helps maintain a compact shape for the following year.

Keep your bigleaf hydrangea healthy from here

Save your plant in Pocket Botanist and you get care reminders timed for this plant, plus a care history that shows what worked. Identification and a health check are free.

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Questions people ask

Can I cut back the long stems now?: It is best to wait until after the hydrangea has finished flowering. Cutting now might remove the buds for next year.
Will these stems ever get thicker?: Existing stems will harden over time, but they likely will not thicken significantly. Pruning them back later will encourage new, stronger growth.

Why is my bigleaf hydrangea looking so leggy?