How to Prune a Snowball Bush

Co-authored by Lauren Kurtz

Last Updated: December 10, 2022 References Approved

Snowball bushes are known for the puffy, white flowers that bloom on them year after year. What many people don’t realize is that several different plants are called snowball bushes. Viburnum bushes bloom in the spring, while hydrangea bushes bloom in the fall. Depending on which variety you have, make slight adjustments to your pruning routine in order to help your plant thrive.

Method 1

Method 1 of 2:

Pruning Viburnum Snowball Bushes

1
Prune the bush after the flowers bloom in spring. Expect viburnum snowball bushes to blossom in May. Heavy pruning should only be done at this time since you can easily destroy next year’s flowers by removing old wood.^{[1]
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- Deadheading, or cutting off the flowers, won’t harm viburnum. However, doing it isn’t necessary and prevents the plant from growing berries.
2
Cut the oldest shoots near the ground. The oldest branches are the thickest, woodiest ones. They may produce side shoots or have flaky bark that make them easier to recognize. Using a clean, sharp pair of shears, cut as close to the soil as you can to completely remove the shoots.^{[2]
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- At most, remove no more than ⅓ of the shoots. Usually, this means removing 1 to 3 shoots at a time.
- Leave behind the thinner, fresher shoots coming up from the plant’s base. These will rejuvenate your viburnum.
- Although the snowball flowers bloom on old wood in viburnum plants, the oldest shoots produce weak flowers and are safe to remove.
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3
Trim the sides of the plant into shape if needed. Viburnum often grows well when it is left alone, so you may not need to do routine trimming. If your bush gets too large or begins extending out of its spot in your yard, use clippers to reduce its size. Cut the branches as needed.^{[3]
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- Remember to only perform hard trimming in spring, after the bloom, to avoid damaging the bush’s buds the next year.
- You can trim the branches this way to maintain the snowball bush’s rounded shape or sculpt it into a hedge.
4
Reduce the bush’s height by ⅓ if it becomes overgrown. Viburnum snowball bushes grow relatively quickly, so they can become too tall or crowded. If your bush needs serious work, use shears to trim the shoots and branches back. You can also cut out the larger, older shoots to thin the plant.
- The best time to do this is around May, after the flowers bloom, although it can be done anytime as needed.
- After trimming back the plant, you may want to wait and watch it grow back. Then you can see where you need to thin out the branches.
- By maintaining the bush regularly, you likely won’t need to do this.
5
Trim damaged branches down to the new growth throughout the year. Examine your snowball bush throughout the year to look for broken or rotting branches. With a sharp pair of shears, cut out the damaged parts. If possible, cut above the nodes, which are where new leaves and branches grow off of the old branches.^{[4]
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Royal Horticultural Society
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- This routine trimming should be done year-round to keep your snowball bush healthy and thriving.

Method 2

Method 2 of 2:

Maintaining Hydrangea Snowball Bushes

1
Prune snowball hydrangeas after the first frost in fall or winter. Wait for the first frost to happen in your area. This happens when the temperature reaches 32 °F (0 °C) and the ground freezes over. Snowball hydrangeas go dormant, so you can perform heavy pruning during this time.
- Hydrangeas flower on new wood.
2
Trim all the branches down to10 in (25 cm). Aim to make each branch between 4 to 10 in (10 to 25 cm) long. Use a clean pair of shears to cut the branches cleanly. Shorter branches will produce larger, stronger snowball flowers during the next growing season.^{[5]
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University of California Division of Agriculture and Natural Resources
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- You can cut snowball hydrangeas to the ground every year. This usually isn’t necessary and can weaken your plant over time, so only try doing this every 3 or 4 years.
- You don’t have to deadhead hydrangea since you remove the old blooms when you trim back the branches.
3
Cut older branches back to the growth nodes. Check the branches for thick spots where new buds form. Trim thick, woody branches right above this point. Doing this encourages the plant to grow new branches, which can be helpful if your bush looks a little thin or ragged.^{[6]
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University of California Division of Agriculture and Natural Resources
Extension program of the University of California system devoted to educating and improving local communities
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- Try to trim some of the old branches back every fall so your hydrangea always has fresh growth.
4
Remove damaged branches throughout the year. Check the hydrangea often, looking for branches that are splintered or rotting. Also note any tangled or weak stems. Clip these off as you find them in order to keep your plant healthy.^{[7]
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University of California Division of Agriculture and Natural Resources
Extension program of the University of California system devoted to educating and improving local communities
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- Through routine maintenance, you can reduce the amount of pruning you need to do in the fall.

Community Q&A

Question

Some branches did not have blooms this year. Do I need to cut them back?

The pro girl

Community Answer

If you want, but you do not have to.
Question

Should I cut off old blossoms?

Pamela White

Community Answer

Some garden manuals say to cut off blooms after they die. Others suggest to just leave them. I have done it both ways but prefer to leave them alone. It keeps them safe from disease during the summer season.