Pruning petunia flowers is often a necessary task for promoting longer blooms.
The process of pruning or pinching the flowers is called deadheading.
Petunia is a genus of flowering plants with over 20 species of which most are annuals.
They bloom in the summer, producing vibrant flowers for several months.
Many of the cultivated varieties are hybrids with new varieties appearing regularly.
Some of the newer hybrids don’t require deadheading to prolong the bloom.
Check the Petunia care instructions on the seed packet or flower marker.
If the petunia requires deadheading, it may not bloom profusely without occasional pinching or shearing.
When to Deadhead Petunias
Start deadheading petunias when the first blooms show signs of dying. and the flowers appear wilted.
As petunias tend to bloom at the start of summer, the plant may be ready for deadheading several weeks into the season.
After the initial bloom, the flowers start to brown and fall off. The plant then starts producing a seed pod.
The goal is to deadhead the spent blooms before the plant starts producing seed pods.
Petunias grown in containers tend to require more frequent deadheading compared to garden petunias.
Without deadheading, the plant may only produce a single bloom.
The petunia spends the rest of the season with straggly stems and no flowers.
Deadheading isn’t required, but removing the old blooms promotes new growth.
Clipping off the wilted bloom and the emerging seed pod forces the plant to restart the process, producing a new bloom.
Deadheading is typically performed about once per week throughout the summer.
When cooler temperatures arrive in the fall, the plant should stop producing flowers.
After deadheading, apply a 10-10-10 fertilizer.
Using fertilizer and performing weekly deadheading gives the plant time to heal.
How to Deadhead Petunias with Pinching
Several methods exist for deadheading petunias, including pinching and pruning.
Pinching is recommended for novice horticulturalists as pruning requires special care.
- Pinching involves grabbing the spent flowers with fingers and pulling them off.
- Locate the dead flowers on the plant.
- The spent blooms are often found below new blooms.
- Use a thumb and forefinger to grasp the flower just above the bud.
- As you pinch, the flower should come off the stem easily.
- Pinch the remaining spent blooms on the same stem and then move on to another stem.
- Repeat this process each week to remove dead flowers during the growing season.
- Pinching is also useful for dealing with leggy growth.
- At about mid-summer, pinch stems starting to hang toward the ground.
- Locate the thickest bud near the top of the stem.
- Use a thumb and forefinger to pinch off the stem just above the bud.
- This process makes the foliage appear thicker and promotes a healthier plant.
How to Deadhead Petunias with Pruning
After one or two seasons of pinching, try pruning.
Pruning includes many of the same steps used for pinching.
Instead of fingers, this process requires sharp, clean gardening shears or scissors. Felco #2 hand pruners are our favorite.
- Before using shears or scissors to prune the plant, sterilize them.
- Dip the pruning instrument in a solution containing equal parts of water and rubbing alcohol.
- Allow the scissors or shears to soak for five minutes and air dry.
- Examine the plant, looking for stems containing multiple spent blooms.
- Cut up to half of the stems using the sterilized shears or scissors.
- Cut back the flower stem just below the spent blooms.
- The number of stems pruned each week depends on the size of the plant.
- Too much pruning may harm the plant, limit the number of flowers, and result in a less attractive plant.
- Trim one stem per week on small petunia plants.
- Large plants with dozens of stems can withstand additional pruning.
- Trim up to ten stems on larger plants.
- If weekly pruning isn’t an option, plan on pruning most of the plant about halfway through summer.
- Toward the end of July or early August, remove all spent blooms.
- Remember to fertilize the plant to reduce the impact of massive pruning.
Which Petunia Varieties Require Deadheading?
Popular varieties benefiting from deadheading include Grandiflora and Floribunda.
Grandiflora is the largest variety of petunias with flowers reaching up to 4″ inches wide.
Floribunda petunias produce medium-sized flowers measuring 2″ to 3″ inches wide.
These plants are vigorous growers but need deadheading throughout the summer to encourage new growth.
Some of the newer hybrids are low-maintenance plants requiring no deadheading.
Surfinia is a Grandiflora hybrid not requiring frequent deadheading but may still benefit from one pruning session in the middle of summer.
Wave petunias are self-cleaning plants.
The flowers eventually wilt, dry up, and fall from the plant.
New blooms appear without the need for deadheading.
While some varieties don’t need deadheading, the stems may need pruning to prevent leggy growth.
Cut the stems back to about half their length in the middle of the summer to promote fuller foliage and blooms.