Hello,

The hydrangea that blooms on old wood only, the one in the middle is a Hydrangea macrophylla—also known as big leaf or mophead hydrangea. Since it flowers on old wood and blossoms late, you should leave the old dry flowers on the plant for winter interest and to protect the coming season’s flower buds. Prune in the spring, cutting stems that have flowered back to the fat flower buds. You can also thin excess twiggy growth to let in more light.

The other hydrangeas, are cultivars, probably Endless Summer which is remontant, that bloom on old and new wood. It is recommended that you prune it in the spring, just like the Hydrangea macrophylla. You could watch the attached Youtube videa on the maintenance of Endless Summer hydrangeas. https://www.youtube.com/watch?v=zgAYF0-6hnc

“Getting the most from your Endless Summer Hydrangea.”

And here: https://www.youtube.com/watch?v=L6LOS8orBrE “Spring pruning for your Endless Summer Hydrangea.

It seems that the larges plants are outcompeting the middle one for sun, water and nutrients which may be why it did not flower well this year. You could consider moving the middle one to another location and it may flower more readily.

I hope this helps you with your hydrangeas.

Thank you for contacting Ask Extension.

Hello again,

According to Cass Turnbull in her book ‘Guide to Pruning’, mophead “hydrangeas can be made to look better by following the rules of selective pruning. First, take out the deadwood. Then take out the worst crossing/rubbing canes, especially those that are crowded in the center. Cut off canes lying on the ground, or growing out too far. The canes can be cut to the ground or to a promising side branch, node or bud down inside the shrub.”

When it comes to size reduction, hydrangeas can be managed by annually cutting them to 3-12 inches above the ground. Hard pruning like this usually results in in larger blooms and leaves but may be floppy. Sometimes the plant will bloom in the same year or they may not in the first year after blooming. The shrub will probably be back to its original size 2-3 feet 2 or 3 years later.

The best time to do this pruning would be early spring.

I hope this helps.

Thank you for contacting Ask Extension.

You're welcome.