Answer: I'm not sure whether your soil is naturally too high in lime or if you applied too much lime to your garden. If you apply too much lime, your soil will become extremely alkaline. In soils that are too alkaline, nutrients such as iron, manganese, zinc and phosphorus become inaccessible to plant roots. It can take 3-4 years for the lime to degrade. If your soil is naturally too high in lime you'll want to plant things that tolerate alkaline soils. I suspect you added too much lime if your hydrangea is blue. Acidic soils make hydrangea flowers blue; alkaline soils turn them pink. You won't need to do anything for your hydrangea to produce pink blooms if you added lime.
Best wishes with your garden!
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