Hydrangea macrophylla, or Big Leaf Hydrangea is arguably the most popular garden Hydrangea on Long Island. In fact it’s rare to come across a yard that doesn’t have at least one. These beautiful summer flowering shrubs are covered with blooms most of July and into August boasting beautiful “mop-head” and “lace-cap” type flowers in colors ranging from white to shades of pink, purple and blue (color will be dependent upon the soil chemistry… but that’s a discussion for another day). Unfortunately, this spring has shown that a lot of them have died back considerably. Most, if not all of last year’s stems and branches have perished and many of them are only showing signs of growth from the base of the plant.
Why did this happen?
Several factors come into play here:
The hydrangeas’ flower buds do not have very good protective “shells” for dormancy… In fact, it is known as a “naked bud” because instead of a hard protective shell, hydrangea buds are housed by under develop leaves. This unfortunately leaves the buds susceptible to damage in extreme conditions.
And extreme conditions we had! With the combination of the very cold and long winter, and that we experienced late frosts this past early spring after some initial warm up, many of the buds and stems were damaged severely (Some will argue that last summer’s drought has had a role in this as well, as last year’s growth was stressed and now weaker than normal) . In a few rare occurrences, some hydrangeas faced complete death, but for most, the plants are recovering with new growth from the base of the plants.
What does this mean?
Well… unfortunately, most Hydrangea macrophylla, especially older cultivars, produce their flower buds on the stems produced the year before they bloom. Due to the damage, these plants will most likely not bloom, or only produce a few blooms this year. The plant will recover in size and set buds for next year (barring any extreme conditions, of course). Some of the newer remontant (re-blooming) varieties will still bloom, perhaps later in the season, or weaker than normal, or look be completely normal… but they will still produce flowers due to their ability to produce flowers on old and new wood.
What should be done to ensure strong healthy growth?
By keeping your plants healthy, they will have a better chance of making it through tough conditions. All trees and shrubs, but especially our suffering Hydrangeas will benefit greatly from the following:
• All of the dead and damaged branches need to be pruned away, making clean cuts back to where the plant is still alive.
• Fertilization with a slow-release, organic fertilizer infused with beneficial microorganisms, like Espoma Plant-Tone (Holly-Tone for blue Hydrangeas) or Dr. Earth brand products. The Dr. Earth Metabolic Transformer is especially helpful for these situations
• A ½” to 1” layer of compost around the base of the plant out to its drip line (or previous drip line in the case of our struggling Hydrangeas)… be careful not to suffocate the crown of the plant.
• A 1 to 2” layer of organic mulch… again, be careful not to suffocate the crown of the plant
• Ensure the plants receive adequate moisture to prevent stress to the new growth.
While it may be a disappointing Hydrangea season for many of us, the vast majority of our damaged plants will recover to produce their aww-inspiring blooms once again. For those of us looking to add new Hydrangeas to your garden, I strongly suggest purchasing cultivars with remontant (re-blooming capabilities) as they have proven to be strong bloom producers through harsh conditions. There are also other species of Hydrangeas that produce their flowers on new growth, and therefore are not affected by harsh conditions. H. arboresecens or the Smooth Hydrangea, the most popular cultivars being ‘Annabelle’, and ‘Bella Anna’ . And H. paniculata, or the Panicle Hydrangea, with many popular varieties like ‘Limelight’, ‘PeeGee’, ‘Pink Diamond’ and many many more.
See our staff interviewed about Hydrangea on CBS-New York by clicking here.