When Should Hydrangeas be Pruned?

Many gardeners feel like hydrangeas are one of the most confusing shrubs to prune. When trimmed correctly hydrangeas will produce big beautiful blooms year after year. If you trim it incorrectly you could be left with a flowerless bush for several years.

So how do you know when is the best time of year to prune your hydrangea, especially when there are so many different varieties?

Supplies you may need to care for your hydrangeas:

Knowing if your shrub blooms on old or new wood is key

Not all hydrangeas should be pruned at the same time of year. Those that bloom on old woody growth should only be pruned after flowering. Others bloom on new growth and should be pruned before as they are growing dormant in the fall but before they "wake up" in the spring.

If it blooms on old wood do this:

To determine if your hydrangea blooms on old wood, notice when it flowers. Shrubs with flowers that grow on old wood generally begin blooming in early summer and stop by midsummer, though sporadic blooms may appear afterward.

These shrubs form next year’s flower buds in late summer or early fall as the days get shorter and temperatures cool off. To reduce the risk of removing these buds, prune just as the flowers begin to die.

Often, the earlier you get it done after bloom, the quicker the shrub can recover, producing more and larger blooms next season. Snip off spent blooms just below the flower head and remove any wayward or straggly canes at the soil line.

When a hydrangea gets old and woody, it can produce smaller blooms. Regular removal of a few of the oldest canes at the soil line can keep the shrub lively, producing large and colorful flowers. The same method can keep a shrub from getting too tall by targeting the tallest branches for removal.

If your hydrangea blooms on new wood do this:

Cut these shrubs back in late winter before new growth begins. Because they need to grow and set buds the same year that they bloom, shrubs that flower on new wood generally start blossoming later than old-growth bloomers, beginning in midsummer and continuing until the first frost. These shrubs are forgiving if pruning is not done at a certain time as long as you avoid pruning after the flower buds start blooming.

To get bigger flowers, cut them all the way back to the ground in late winter or early spring. Hydrangeas will produce much larger blooms if pruned hard like this every year.

When Should I prune an Endless Summer hydrangea?

The great thing about Endless Summer hydrangeas is that you don’t need to prune them back to the base like other hydrangeas. They bloom on previous years’ growth and the new season’s growth, so you can leave them all winter long to achieve double the blooms next spring.

Don't prune Endless Summer hydrangea back in fall. Leaving the fall blooms on your plants over the winter provides winter interest, and ensures you aren’t removing buds that will become flowers in the spring and summer.

If you pruned your hydrangeas back to the base, it will take some time for the new growth to develop and produce blooms. Be patient and look for the green growth coming up from the base of the plants. That is where your new blooms will grow from.

How do you fertilize hydrangeas?

Hydrangeas should be fertilized with fast-release fertilizer in March, May, and July. Be sure to spread it around the drip line of the branches and not the base. Water well. If the fertilizer you choose is a slow-release type, remember to lightly cover it with soil to activate the fertilizer

What should you feed hydrangeas to make them bloom?

Most hydrangea’s will grow flowers that are either blue/purple or pink. If you want to encourage blue blooms you need to make the soil more acidic. Add aluminum sulfate, composted oak leaves, pine needles or coffee grounds. To encourage pink blooms you must make the soil more alkaline. You can do this by adding wood ash, lime or fertilizers with high levels of phosphorus to prevent aluminum from entering the plant’s system. A ratio of 25-10-10 is best.

Do coffee grounds make hydrangeas bloom?

Coffee grounds won’t make a hydrangea bloom but it can affect their color like explained above. Coffee grounds add extra acidity to the soil around hydrangeas. On a chemical level, this increased acidity makes it easier for the plant to absorb naturally occurring aluminum in the dirt. The effect is pretty blue clusters of flowers.

How many times will a hydrangea bloom?

Common Hydrangea

These hydrangeas bloom earlier than some other varieties, often with blooms forming in May. The plants typically continue to develop blooms into July.

Big Leaf Hydrangea

Big leaf hydrangeas are known to change bloom colors based on the soil properties; a plant that blooms pink one year can bloom blue the next. These varieties will bloom later in the year, closer to August and into the fall.

What's your opinion? When should hydrangeas be pruned? Let me know your best tips and tricks in the comments!