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Yellowing leaves onhydrangeasdetract from the balanced appearance of these big-leafed shrubs.
In colors varying from medium to dark green, hydrangea foliage provides a contrasting backdrop for dramatic blooms.
Different patterns and degrees of chlorosis in the leaves offer clues for finding and correcting the problem.
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Improper Watering
Considering moisture problems is the best place to start.
These issues are easy to identify and fix if you take steps beforeroot rotsets in.
Amoisture metercan help guide you to the best method of correction.
Overwatering
Large leaves often look droopy during the afternoon heat.
Limp leaves turn yellow before brown and mushy, and eventually fall off.
Other signs include stunted growth, fewer and smaller blooms, and blooms that appear wilted.
The plant can develop root rot.
If the soil is overly wet and soggy, the hydrangea is overwatered.
Underwatering
Underwatering also causes leaves to turn yellow with brown, crispy edges.
Don’t take a stab at correct the problem by watering excessively.
It can make the situation worse.
Irrigate deeply until the soil surface is slightly moist.
You may need to increase frequency.
Remember that a deep watering two to three times a week is generally sufficient.
Addmulchto help retain soil moisture.
Poor Drainage
Hydrangeas thrive better in loamy, sandy soils than in clay soils.
This increases the possibility of overwatering.
Choose a location with well-draining soil and avoid areas where rainwater puddles.
Working aged compost and sand into the soil around an existing hydrangea helps improve drainage.
Avoid improper sun exposure by choosing an appropriate location or relocating the shrub if possible.
you might do a home test to check for appropriate pH levels.
Plants use lots of nitrogen and can deplete soil quickly.
Working in compost and applying a spring treatment ofbalanced fertilizerfor acid-loving plants helps defeat this problem.
Iron
When new leaves turn yellow but veins remain green, the hydrangea is likely iron deficient.
This is sparked by overwatering, poor drainage, improper fertilization, and highalkaline soil.
Look for fertilizers formulated for acid-loving plants with iron as an ingredient.
Compost with oak leaves, pine needles, and coffee grounds helps raise soil acidity.
The soil-pop in hydrangeas prefer often lack magnesium.
This makes correcting this problem a little trickier.
Epsom salts and dolomite lime add magnesium, but lime also raises pH and should be used sparingly.
Try spraying foliage with a liquid seaweed extract.
Avoidfertilizerswith a high percentage of potassium which interferes with magnesium uptake.
Use products for acid-loving plants like hydrangeas and azaleas and follow package directions.
Disease
Hydrangeas are susceptible to fungal,bacterial and viral diseases.
Hydrangea mosaic virus and tomato ringspot virus cause yellowing of foliage.
Good sanitation practices help prevent mosaic virus.
Use sterile tools for pruning and spraying your pruner between cuts to prevents potential spread.
Tomato ringspot virus is triggered by nematodes.
Look for varieties with disease resistance.
White and yellow spots are followed by holes and eventual defoliation.
Early signs of spider mites include fine webbing.
Check the undersides of leaves for damage andapply neemor horticultural oil.
An overwatered hydrangeas has leaves may be yellow or yellow with green veins.
Foliage appears limp and wilted.
The plant produces fewer flowers that may also look droopy or wilted and stunting can occur on new growth.
To fix yellow hydrangea leaves with soggy soil, delay watering to give it a chance to dry out.
Adjust soil pH to correct levels.
Spray leaves with seaweed extract or work epsom salt solution into soil around the hydrangea.
