Non-Blooming Hydrangeas

(Question)

A common question, I know. But I’m stumped. I have 3 lovely, healthy 8-year old hydrangea plants (3′ tall) in a sheltered, dappled shade, sandy soil location. They’ve NEVER bloomed. I do not cut them back and I have other hydrangeas in the garden that boom regularly, which are in less sun. Any suggestions for what I can add/do to promote blooms? They are right off our deck, so I’d love to have them blooming like I’d intended. Thx!

(Answer)

Eight years without any blooms – that’s pretty amazing. I am surprised you have not given up on these hydrangeas. You are right it is a mystery.

If you want your hydrangeas to bloom it is extremely important to know what kind you are growing.  Some of them grow flowers on new wood and some on old wood. If your hydrangea won’t flower, then you need to figure out which variety you have planted. It would appear that they are different from the ones that bloom for you. The main reason hydrangea do not bloom is due to incorrect pruning.  However, you indicate that you do not prune your non-flowering hydrangea.

Hydrangea that bloom off of new wood usually are not problematic. These would include Annabelle and PeeGee varieties.  Hydrangea that bloom on old wood are the troublesome ones. These are the big leafed species (Hydrangea macrophilia) which happen to be the most popular. Even if you have not pruned, these cultivars can die back in the winter, particularly if there’s been a colder than normal winter or a late frost. If the old wood dies , your hydrangea won’t bloom when it grows back the following year. This is because it’s growing new wood and the new wood doesn’t produce flowers on this particular variety. You have to wait for the following year. Your case is a bit of a mystery because this has been going on for 8 years. Try protecting your plants this winter by surrounding them with burlap and see if that makes any difference.

Perhaps the lack of blooms is because you have planted a variety that does not do well in your zone.  Maybe your plants do not get enough sun for the variety. They need at least 4 hours. All reasons for trying to identify the variety of hydrangea you own.

None of the above really seem to apply to your situation. Perhaps it is the soil. It might be worth your while having your soil tested. When was the last time you fertilized? Too much nitrogen or a lack of phosphorus in the soil could be the reason there are no flowers. An abundance of nitrogen produces lush green growth, but little to no blooms. Phosphorus is responsible for the flowering and fruiting in most plants, so the addition of a phosphorus-rich fertilizer may be all that is needed to correct this. Bone meal is a great way to add phosphorus to the soil.

For further reading check out the following links:

https://www.clemson.edu/extension/hgic/plants/landscape/shrubs/hgic1067.html

https://web.extension.illinois.edu/dmp/palette/110724.html