How & When to Prune Petunias
Learn the recommended approach to pruning petunias so they continue to look healthy and produce multitudes of blooms all season
Photo by: Nata Lunina / Shutterstock.
Petunias are beloved for the many blooms they produce all throughout summer. Though they’re known for being a low-maintenance annual, a little effort will keep them looking their best. To encourage an eye-catching show from your petunia plants, a little pruning is required.
WHY PRUNE PETUNIAS?
Pruning petunias is good for the overall health of the plant. In addition to promoting more flower production, it also encourages new growth and keeps the plant tidy and full.
HOW DO YOU PRUNE PETUNIAS TO KEEP THEM BLOOMING?
To keep petunia flowers blooming all summer long, you’ll want to prune your plant about three times during the summer, taking care to cut off just the right amount to still enjoy your plant while also encouraging new growth.
Read on for details about pruning petunias including when to prune and how far back to cut.
WHEN SHOULD PETUNIAS BE PRUNED?
When you trim back your petunia plant, give it a dose of water-soluble fertilizer to help the plant create new growth.
Here’s a general pruning schedule based on a petunia that was planted in spring.
- Beginning of July. Give your plant a light pruning after its vigorous growth in May and June. For this pruning, you’ll want to cut back about one-third of the branches, focusing on the ones that are getting long and straggly. This will stimulate new blooms.
- Mid-August. Remove anything that looks straggly and any especially long branches until the plant looks shaped. Like your light pruning in July, don’t cut back more than about one-third of the branches.
- Mid-September. This will be your last pruning of the season. Take the same approach as the previous two prunings, leaving about two-thirds of the plant alone.
HOW FAR CAN YOU CUT BACK PETUNIAS?
Petunias don’t benefit from a hard pruning, so be sure to have a light touch as your prune, only removing long stems—especially the ones that are beginning to look leggy. Don’t prune back more than one-third of the plant’s stems.
When you prune, rather than cutting the stem all the way back, just cut off enough of it to shape the plant nicely and remove the leggy growth.
CAN I CUT BACK LEGGY PETUNIAS?
Yes. If you see leggy growth and it’s not time for one of your three summertime prunings, you can still remove the straggly growth as you see it. In fact, it’ll keep the plant looking healthier longer if you do.
HOW DO YOU TRIM POTTED PETUNIAS?
Watch this short video (about 1.5 minutes) to see how to prune your potted petunia.
For potted petunias, use the suggested pruning schedule above (cut back in July, August, and September). You’ll also want to follow the same guidelines when it comes to how much to cut off—only cut back about one-third of the petunia stems each time.
Trimming potted petunias is often considered simpler than trimming petunias planted in garden beds—especially when they’re in hanging baskets. When they’re in a pot, it’s somewhat easier to shape the plant, using the pot as your guide.
SHOULD I REMOVE WILTED FLOWERS?
As blooms expire, deadhead them to encourage flower production. Simply pinch the stem or use pruning shears to completely remove the dead blooms. (These micro-tip pruners work great!)
It’s important to not just pull off the petals of the spent flower—instead, remove the entire flower including the seed pod. That way the plant will work to produce flowers rather than seeds.
Read more about how to deadhead petunias.
Supertunia Vista® Bubblegum® petunia.
Photo: Proven Winners.
DO SUPERTUNIAS NEED TO BE PRUNED?
While Supertunias are self-cleaning and don’t need to be deadheaded, they do benefit from a trim a few times during summer. When trimming, cut back about one-third of the plant and then give it some fertilizer to support the plant as it works to create new growth.
See more on how to care for Supertunia® petunias.
