Where would we be without pansies (Viola spp.)? The beautiful flowers add nonstop color to the chilly days of spring and fall, and even brighten up the winter months in warmer regions.
I always have potted pansies and violets on my patio from October through April, and sometimes they’re the only color besides green in my yard.
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I’ll even pop one of the edible flowers onto my salad now and then to cheer up my winter meals.
These plants are resilient enough to survive and even keep blooming through a heavy freeze. They can often perk back up after being buried in snow for a few days. They’re a lot tougher than they look.
But then summer rolls around, and the plants don’t always look so healthy. Heat is their Achilles heel.
In our guide to growing pansies, we cover how to cultivate these colorful, easy-care flowers in your garden.
This guide explains what kind of temperatures species in the Viola genus can tolerate, what to do with your plants during the warm weather, and we’ll even offer up a few options that will tolerate a bit more heat than most.
Here’s what I’ll cover:
What Temperatures Do Pansies Prefer?
Pansies, violets, and violas are much happier on the cooler end of the temperature scale than in heat.
Depending on the cultivar, they can survive down to 15°F, though most will suffer some cold damage or stop blooming when temperatures drop below about 25°F.
This damage primarily comes from the roots being unable to take up water when the soil is frozen rather than the freezing temperatures themselves.
You might see the leaves and flowers turning mushy if the plant is suffering from freeze damage.
On the other end of the scale, when the temperature starts to creep into the mid-70s, the plants begin to go dormant.
Species in the Viola genus are known as facultative long-day plants, which means that they are influenced to bloom by the number of daylight hours but they will still bloom any time of year regardless of daylight hours.
They just flower more rapidly and abundantly when the number of daylight hours is 14 or over.
What this tells us is that the number of daylight hours promotes blooming but it’s the temperature that causes them to stop flowering, not the arrival of summer.
If the temperatures stay cool longer than normal, or turn hot earlier than normal, the flowering will be influenced.
Learn more about when pansies bloom in our guide.
You might have noticed that violets become long and leggy during the longer days. That’s because the flowers fade more quickly without giving the plant time to develop lateral shoots.
One day of high temperatures won’t hurt them. It’s when the conditions are hot day after day that things get dicey.
Whether they flower or not also depends on how much the summer temperatures drop at night. It’s the average temperature measured over 24 hours that is important.
Let’s say the temperature climbs to 90°F during the day, but it drops to 45°F at night. That makes the average around 67°F, which is low enough to keep the plants happy.
On the other hand, if it’s 95°F during the day and 65 at night, the average is 80°F. That’s too hot for pansies.
So whether your flowers are happy or not might depend more on the nighttime temperatures in your region than the heat of the day.
How to Care for Pansies in Summer
When the weather starts to warm up, you might be tempted to dramatically increase the amount of water you’re giving your plants, but this isn’t a good idea, as they enter a dormant state and the roots won’t absorb as much water.
Just keep watering them consistently so the soil remains evenly moist but not waterlogged. It’s very easy to overwater and cause root rot.
On the other hand, not enough water will cause your plants to dry out and eventually die. So try to keep the amount of water consistent throughout the year.
You can cover your plants with shade cloth to shield them from the heat of the day and the afternoon sun, this will help keep the temperatures around them a bit lower.
Many gardeners treat their pansies as annuals and just toss them out when the weather gets too hot, and that’s certainly an option.
You can keep your pansies in place, providing consistent water and a bit of shade, and most will survive unless it is extremely hot and sunny. They just won’t bloom.
I keep mine during the summer and they stop blooming when the temperatures are consistently above 80°F, but the greens stick around.
Then, in the fall, when the temperatures start to drop, they pick back up – but I live in a region with relatively mild summers.
Even if you do live somewhere that experiences very hot summers, if you plan ahead and put your plants in a spot that is protected from direct sun in the afternoon, yours should be fine.
They’ll start blooming again when the weather cools off a bit in autumn.
As the temperatures start to rise, trim back any remaining or spent flowers and pinch the plants back a bit to remove any leggy growth.
Go ahead and surround them with other low-growing summer annuals to jazz up the area.
If you have a plant that you adore and you don’t want to give up on it, you can also bring it indoors to grow as a houseplant during the hottest time of year.
The climate in your home is probably a lot cooler than the great outdoors. Just make sure the plant receives plenty of direct light.
Cultivars that Tolerate Heat
While there aren’t very many heat-tolerant pansy cultivars available, there are a few that have been bred to tolerate heat better than others.
Cultivars in the Delta series, Majestic Giants, ‘Matrix,’ and ‘Purple Showers’ will all last longer into the summer than most.
The Delta series is available in a variety of colors, including purple, yellow, several reds, blue, orange, and white.
Delta Series Mixed Seeds
You can pick up packets of 25, 200, or 500 seeds at True Leaf Market.
Keep in mind that while they are definitely more heat-tolerant than winter pansies (V. hiemalis), for example, these types won’t thrive in sweltering conditions.
None of them are going to do well when it’s in the 90s.
If You Can’t Take the Heat…
Some plants shine during the summer and others pick up the slack in the spring or fall.
Pansies are perfect for providing color in the garden during the cooler months.
But how can you be expected to say goodbye to the colorful faces of your Johnny-jump-ups just because the sun is getting more intense?
Until someone breeds some new cultivars that thrive in the heat, we’ll have to do our best to enjoy them while we can. What’s your plan? Will you pull them? Let them hang out as greens? Let us know in the comments section below.
And for more information about growing pansies, check out these guides next:
