Deb sent me an email the other day telling me that she has three hydrangeas that will not bloom for her. The year of the flood (2008) one of them bloomed, so that flood water must have had some good stuff in it. Otherwise, nada.. no blooms.
Well, hydrangeas love water. We found that out the first year we had our ‘Endless Summer’ hydrangea. It kept drooping a couple of days after we would water it. We ended up watering it with five-gallon buckets of water every other day. That seemed to keep it happy. So maybe that is what happened with the one hydrangea that DID bloom for Deb… it finally got the water it thought it needed!
Other problems are too much shade, having the wrong type of hydrangea, winter kill and pruning too much (although I think that is more of a problem on the southern zone plants).
There are several varieties of hydrangea and many of them are not hardy in our state. These put out blooms on the old wood. The problem is that in Iowa, our winters tend to kill off that old wood. You need to make sure the variety you have can either be saved by keeping it well covered (which probably won’t work) or blooms off of new growth. ‘Endless Summer’ and ‘Annabelle’ are two varieties that are hardy in Iowa. If you manage to get one of the not-necessarily-hardy varieties, make sure you know if it blooms on new growth or old growth before you prune anything. The oakleaf hydrangea is a beautiful one to get. Its leaves are shaped like oak leaves and the foliage turns burgundy in the fall.
If the hydrangea is buried too deeply, it won’t bloom. It may be in too much shade, although ours in on the east side of our house and is in shade for half of the day. They prefer rich, well-drained and consistently moist soil and if there is too much nitrogen in the soil with will keep the energy focused in root and stem growth and not the flowers.
One of the most fun things about the ‘Endless Summer’ hydrangea is that you can pick which color of flower you want. Do you want pink?
In order to get blue blooms, you need aluminum in the soil. This is only available to the plants when the soil pH is low. So, if you want blue flowers,
you need acidic soil. You can buy aluminum sulfate at your local nursery. To get the pink blooms
you need to increase the pH. Adding high levels of phosphorus fertilizer to acidic soil should prevent or limit the plant’s uptake of aluminum. Adding lime to the soil will increase that pH. If the soil pH is somewhere in between the acidic and alkaline, the plants may produce a dull green or purple colored bloom.
And in some plants, you can have both!
We didn’t add anything to the soil around the hydrangea last summer and the plant has blue blooms near the house and pink blooms away. I bet you can tell which side of the plant is more acidic!
I have both aluminum and the lime. I wonder which one I should go for this year…. Let me know what you think.