How To Revive Dying Petunias

Petunias have earned the bragging rights and a seat at the table of popular flowers.

With their brightly-colored, trumpet-shaped flowers, they make awesome garden borders and indoors, easily infuse life into any drab room.

Understandably, folks are wild about the long blooming period that can last from spring through the fall until winter sets.

These prolific bloomers do require a bit of attention to keep them in top shape in the growing season.

But even with the best care, they sometimes show signs of failing and would die if the problem isn’t resolved asap.

This brings us to the focus of this article: how to revive dying petunias.

No prizes for guessing that you are reading this because your lovely petunias seem to be in some sort of pickle and you want to save them.

How To Revive Dying Petunias

Typically sold as single or double bloom hybrids in nurseries and garden centers, the various varieties of petunias (Petunia spp) are grown as annuals in most parts of the country.

In hardiness zones 10 and 11 though, they can be grown as perennials.

Like most popular flowering plants, caring for petunias is super easy.

They grow really fast making regular watering essential to keep up with the growth rate. And with enough sun, expect the awesome rewards in blooms that just won’t stop.

When petunias start showing serious signs of failing especially in the growing season, it’s often due to too much water, dry soil, lighting problems, pests infestation, lack of soil nutrients, and diseases.

Generally, it is easy to get on top of these issues when they crop up.

The key is to catch the problem early. Most importantly though, understanding the causes and symptoms of the problems are super essential requisites to knowing how to revive dying petunias.

Reasons Your Petunias are Dying and the Symptoms

Watering issues

While petunias need watering frequently, they hate soggy or over-watered soil.

Soil with too much water creates the right condition for the growth of soil fungi that cause root rot.

Root rot disease is the leading cause of petunia death in over-watered soil. In the latter stages of the disease, the roots become rotten and are unable to perform their functions of transporting water and nutrients to the leaves.

Other prominent symptoms of root rot include yellowing leaves and drooping.

Keep in mind that over-watering is not the only reason the soil can become soggy.

For instance, poor-draining, compact or heavy soil promotes excessive soil water retention.

This leads to root drowning and ultimately root rot.

For potted petunias, blocked drainage holes (we are assuming you are using pots with drainage holes at the bottom) can lead to waterlogged soil.

At the other end of the scale is inadequate soil irrigation. Persistent underwatering leads to dry soil also known as drought stress.

This can lead to wilting and even worse in Petunias.

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Ideally, petunias flourish when daytime temperatures are between 60 – 75°Fand between 50 -65°F at night.

Daytime temperatures above the 85°F cause wilting as the heat accelerates moisture loss in the plant and soil.

The leaves wilt to minimize the surface area to reduce water loss. But this can go south fast without watering or if the nighttime temperatures remain high for long.

On the other hand, when exposed to temperatures below 40°F, petunias would suffer from frost stress, a situation that is fatal to the plants as the roots lose their ability to function.

For outdoor petunias, this usually occurs in winter. It could also happen in late fall and early spring when temperatures are still lower than ideal.

Lighting Problems

It is often said that to get the best from petunias, simply nail lighting and watering.

Petunias love lots of sunlight. Whether grown indoors in pots or garden beds, they would reward you with healthy blooms and leaves if exposed to at least 6 hours of sunlight daily.

Leggy growth, very few flowers, and a bedraggled appearance are the rewards of inadequate light.

Insufficient soil nutrients

Being fast-growers, petunias need all the nutrient they can get.

The expert advice is to give them a good headstart with compost-mixed soil and then start fertilizing bi-weekly or three times in the middle of the growing season.

Inadequate fertilization causes stunted growth and even death if the problem remains unresolved.

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Petunias, especially when grown outdoors, are susceptible to plant pests such as aphids, ants, snails, and slugs.

All of these feed on leaves and stems wreaking havoc and ultimately killing your petunias.


Petunias are also susceptible to fatal plant diseases such as botrytis blight, powdery mildew, and fusarium thriving in soggy soil.

Unsightly leaf spots, leaf discoloration, and dark grayish spots on leaves are the typical symptoms of botrytis blight.

If the leaves have been completely overtaken by powdery, grey spots and spores, it is most likely suffering from powdery mildew caused by inadequate airflow.

Fusarium infection is a way bigger problem because there is no fix for it.

It’s a fungal disease that attacks the roots, preventing them from absorbing water causing wilting and ultimately dead.

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Steps to Revive Dying Petunias

With proper diagnosis, reviving dying petunias is pretty straightforward.

Since most of the causative factors are linked to incorrect care, simply implementing the right care procedure should resolve the problem.

The steps below outline how to revive your petunias if they are dying:

Prune affected leaves

Cutting back the wilted or dried foliage is the first step and this applies to both potted and garden petunias.

In some cases, you might have to prune almost to the soil level.

This focuses the plant’s resources on growing new stems and leaves.

Check the soil

Check that the soil is neither overwatered nor too dry from lack of water.

If the soil is moist and the last time it was watered was over a week ago, then the roots must be flooded.

Uproot and examine the roots for rot.

You may have to transplant affected petunias to new garden beds after cutting out affected roots.

But, if all the roots are affected, the best course of action is disposal.

You could raise the height of the garden bed to enhance soil drainage.

But if the soil is too dense or compact, amend it by adding more compost to the soil so it drains better,

Keep in mind that soil amendment would require uprooting and replanting the petunias afterward.

Alternatively, use your imagination to create a runoff on the garden beds so that anytime you irrigate, excess water easily drains out of the garden soil.

If the garden soil feels very dry, simply resume watering your petunias.

You would begin to see positive results in a few weeks.

To revive potted petunias with soil and watering issues, these are the applicable steps:

  • For under-watered petunia with rock solid soil, place the pot in a larger container or bucket filled with water for about an hour.

Remove the pot when air bubbles stop rising of the soil indicating that the soil is fully watered.

  • For best and faster results, use a thin metal rod or garden knife to poke holes in the soil.
  • Remove and place it where it is exposed to the morning sun but sheltered from the hot midday sun.
  • Stick to the right watering schedule of watering only when the top 1 inch is dry.

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Adjust the growing conditions

Next, check the conditions the petunia is exposed to.

If the temperature is too high, mist the plants to cool them down or even water them more frequently as this helps to cool the plant and raise the humidity.

If the area is too windy, create windbreakers because winds increase the rate of soil water evaporation to leave it very dry.

To keep the soil cool, spread at least 3 inches of mulch over the soil.

This helps to keep the soil temperature down on hot days.  Mulching also minimizes soil moisture loss and controls weeds.

Examine foliage for pests

Check the foliage carefully for pest infestation. If there are signs and symptoms of infestation, take any of the following steps accordingly:

Aphids – spray them with neem oil or insecticidal soap. You could also introduce ladybugs that feed on aphids to control them.

The best way to attract ladybugs is to grow companion plants like cilantro and radish.

Slugs and snails – use baits or traps specifically designed for them.

Examine the petunias for diseases

If there are signs and symptoms of diseases, do the following:

  • Prune all affected foliage
  • Powdery mildew – spray with neem oil after transplanting some of them. Transplanting creates more space for better airflow effectively preventing recurrence.
  • Botrytis bight – After cutting sick-looking leaves, reduce watering.
  • Fusarium – Uproot and dispose of infected petunias since there is no remedy for this.

To prevent a recurrence, cover the soil where the plants were uprooted with black plastic in summer.

The heat would destroy the soil fungus.

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Fertilize your petunias

fertilization would help to revive them. Apply balanced liquid fertilizer after watering the soil about once every 3 weeks.

When you’ve done all the necessary steps, be patient while keeping to the watering and feeding routines. Before long, your petunias should rebound.

Wrapping Up

Reviving dying petunias might seem challenging especially if you’ve never gone down that route before.

With your basic gardening skills, time, and a bit of patience, you can easily get them back on track.

If you can identify the cause(s) of the problem and recognize the symptoms quickly, you are already more than halfway towards saving the dying petunias.

From that point on, it is simply a matter of applying the corrective measures depending on the observed symptoms.