Can This Common Tree Cause Your Hydrangea Blooms To Stay Blue?

If you're growing hydrangeas in your yard, you probably already know that you can alter the color of the blooms by amending the pH of the soil. You'll find this is primarily true for the big leaf and mountain varieties. In a nutshell, if the soil is acidic, the flowers will be mostly blue but if it has a neutral to alkaline pH, the result will usually be pink blooms. Now, there's a common tree that may be growing in your yard that thrives in acidic soil – the majestic pine. So, if you've planted some hydrangeas under or near a coniferous tree, you might be wondering whether this is causing your hydrangea blooms to stay blue, due to the pine needles that make such a terrific mulch.

This is a common myth that's not true and needs to be explained. In actual fact, pine needles and even pine trees don't acidify the soil – they just naturally love growing in soils with a low pH. So, it's not the tree or the needles it drops that are keeping your hydrangea blooms blue – it's actually the pH of the soil itself. If you wanted to turn the flowers pink, you would need to adjust the pH of the soil. But, you don't want to do this for hydrangeas planted close to a pine because the tree would likely suffer.

Hydrangeas will grow quite nicely beneath pine trees because they provide some welcome shade. In fact, the best spot in your garden to plant hydrangeas is where they'll receive morning sun and are shaded in the afternoon. But, if your tree is thriving thanks to the ideal acidic soil conditions, you'll have to be content with having blue flowers. If you're really bent on having pink blooms, the only preferable remedy is to move your plants to a different space in the garden and then concentrate on altering the soil's pH. Make sure that you only transplant them while they're dormant and have lost all their leaves by following our expert tips on how to remove established hydrangeas from your garden. 

To get pink flowers, hydrangeas need a soil pH of between 6 and 6.5. You'll have to add a lime solution to achieve this but remember to test the pH level first. The Mississippi State University Extension suggests adding one tablespoon of lime to a gallon of water and mixing it well. Pour this blend onto the soil around the base of your plants beginning sometime in spring or early summer. Repeat the application, once a month, for an additional two months. While other things will change hydrangea color like magic too, this is the fastest way to get an effective color change in your flowers.