How and When to Prune Different Types of Hydrangeas

Tools You'll Need For Pruning Hydrangeas

Ready to start pruning your hydrangeas? Here's what you need (and what's optional):

• Bypass pruners: These pruners are the main tool you need for pruning hydrangeas. Bypass pruners function like scissors, with one blade sliding past the other to make a clean cut, which is important for the plant's health. Avoid anvil pruners, which crush branches and can damage the hydrangea. Look for pruners that are comfortable to hold in your hand and have sharp blades.
• Loppers (optional): If you have thicker branches (up to 1 inch in diameter) to remove from your hydrangea, loppers will be a helpful tool. Loppers are similar to bypass pruners but with longer handles and larger blades that can handle thicker branches.
• Pruning shears (optional, for very thin stems): Pruning shears are a good option for trimming very thin stems or spent flowers on your hydrangeas. They are smaller and more maneuverable than bypass pruners but may not be necessary for general pruning.
• Oil for cleaning and lubricating the tools: Keeping your pruning tools clean and sharp is important for the health of your plants and your safety. After each use, wipe down the blades with a damp cloth to remove any dirt or sap. Apply a few drops of oil, like canola or vegetable oil, WD-40, honing oil, or even household three-in-one oil, to the blades to prevent rust. Wipe off any excess oil before storing your tools.

Other Common Questions about Pruning Hydrangeas

What happens if you don't cut back hydrangeas?

Certain hydrangea varieties, like panicle and compact reblooming hydrangeas (like Seaside Serenade®), don't require pruning and may benefit from keeping the dried flower heads over winter for added visual interest in your garden. However, older and larger varieties benefit from pruning.

Remember that skipping pruning won't necessarily harm your hydrangeas in the short term. They may still flower, and some gardeners prefer the natural, unpruned look. Here's what could happen if you don't cut back your hydrangeas:

• Reduced flower size and showiness: Over time, unpruned hydrangeas can develop a leggy appearance with fewer flowers. This is because new flower growth typically happens on younger stems. Without pruning to encourage new growth, the plant puts its energy into maintaining existing branches, leading to smaller and less impressive blooms.
• Tangled and overgrown appearance: Hydrangeas are naturally bushy shrubs, and without pruning, they can become overgrown and messy-looking.
• Potential for disease: Dense, unpruned hydrangeas usually have poorer air circulation, which can create an environment more favorable for fungal diseases.

Should I cut off brown hydrangea blooms?

In most cases, removing brown hydrangea blooms is a good idea. Deadheading keeps your plant neat and tidy and encourages new blooms on certain varieties. However, there are a few exceptions to consider.

Leaving the last blooms on the plant through winter can help protect the new buds in cold climates. Additionally, some hydrangeas, like Seaside Serenade blooms, stay attractive for a long time without turning brown. In this case, it's up to your preference whether you want to remove them or enjoy the color they age.

To deadhead, use sharp pruners to cut the stem of the spent bloom just above a set of healthy leaves. For reblooming hydrangeas, deadhead throughout summer. Stop in mid to late fall to allow the plant to set buds for next year's blooms.

How do I keep hydrangeas blooming all summer?

Here are some things you can do to encourage your hydrangeas to bloom all summer long:

• Provide the right light: Hydrangeas generally prefer morning sun and afternoon shade. Some varieties, like panicle hydrangeas, can tolerate more sun, but all hydrangeas will wilt and struggle to flower if they get too much hot afternoon sun.
• Water deeply and regularly: Hydrangeas are thirsty plants and need consistent moisture throughout the growing season. Aim to water them deeply several times a week, especially during hot and dry weather. The soil should be moist but not soggy.
• Mulch around the base: Adding a layer of mulch around your hydrangeas will help retain moisture in the soil, regulate soil temperature, and suppress weeds that compete for water and nutrients.
• Deadhead spent flowers: Regularly remove faded flowers throughout the summer. This will improve the plant's appearance and encourage new blooms to form.
• Prune strategically: Pruning time depends on the type of hydrangea you have. Bigleaf hydrangeas set their flower buds on old wood, so they should be pruned in late summer or early fall. Other hydrangeas, like smooth hydrangeas, flower on new wood and can be pruned in late winter or early spring.