How Cold Is Too Cold For Flowers To Be Outside? 

It is hard to identify the exact temperature of how cold is too cold for flowers to be outside because there are many types of flowers. Each class has a different tolerance to temperature. Hence, the most effective way to know it is first to understand the kind of flower you have.

That said, we will give you ways to do flower-type identification. Afterward, we will proceed to know the manageable temperature for flowers. Also, their chill tolerance depends on their lifespan and geographical location.

2 Ways To Identify Flower Type

Many gardeners struggle to know the kind of flower they have. However, some are just really not interested to know. Be a responsible grower to protect your flowers and crops too.

Through the flower characteristics

Through the flower characteristics

Identifying the flower type using this method takes a lot of work and effort. A keen eye for details would be great because you will need to check every part of the flower. Long patience is necessary as well.

To utilize this method, check for the following flower characteristic and make sure to record them.

  • Determine the height and breadth of the plant accurately
  • Count the petals on each flower
  • Check the shape of the petals (tubular, lopsided, symmetrical, etc.)
  • Check the color
  • Identify the flower arrangement on the stem (solitary, cluster, umbel, raceme, flowerhead, spike, etc.)
  • Check the stem (smooth or hairy texture, straight or twisted shape)
  • Check the leaves

Note: The process doesn’t stop once you collect all the needed information above. The final thing you should do is to search it on any database (book, encyclopedia, or internet)

The data you collected is useless unless you do the research part.

Through a snap

Through a snap

Yes, you read it right. Taking a picture of your flower may be the easiest way to identify its type. Below are the things you can do to the image you captured.

  • Post it on an online platform where people can see it. Who knows? Maybe someone you know is familiar with the flower!
  • Upload the photo in flower identifier applications. It is more convenient and quick to do.

After you distinguish what type of flower you are growing, it is easier to know their life cycle and place of origin. Consequently, it is quicker to understand their cold tolerance.

How Cold Is Too Cold For Flowers To Be Outside?

How Cold Is Too Cold For Flowers To Be Outside

The general answer to this question is simple. If the cold level drops to 45 degrees Fahrenheit, many flowers will already be affected. However, aftereffects vary and worsen when it drops even lower than the said degree.

We will give you a more concrete example as per the data of the National Weather Service of Northern Indiana.

Frosting happens when the exterior part of the plant gets exposed to coldness. Usually, it takes place when the temperature declines up to 36 degrees Fahrenheit. But, it becomes extensive when it falls to 32 degrees Fahrenheit.

When the temperature reaches the 32 degrees Fahrenheit standard, freezing may now possibly occur. That is not the worst scenario, though, because a hard freeze may still happen at 28 degrees Fahrenheit. In this case, flowers or plants are now vulnerable, which results in mortality.

That’s all you need to know about the general vulnerability of flowers to cold. Now, let us make it more specific using the lifespan and nativity of the flower.

Cold Tolerance Of Flowers According To Lifespan

Flowers have two different lifespans. Some blossoms last only for a year, while the others live longer than that.

Annual flowers

Cold Tolerance Of Flowers According To Lifespan-Annual flowers

These seedlings are categorized based on their tolerance to low temperatures. We will discuss them from the most to less tolerant.

  • Hardy annuals: Hardy annuals are the most cold-tolerant among the three. You can plant these flowers at 40 degrees Fahrenheit. On the contrary, they will surely die when exposed to too much heat. Hardy annual seedlings can only tolerate a slight freeze.  Pansy, sweet alyssum, calendula, larkspur, and foxglove are some examples of hardy annual flowers.
  • Half-hardy annuals: As the name implies, these annual seedlings can survive at low temperatures. A minimum of 40 Fahrenheit will do. These are subject to light frost, so it is better to maintain the temperature at that limit.  Examples of half-hardy annuals are cleome, baby’s breath, forget me not, and strawflowers.
  • Tender annuals: This last category is the seedlings that have no chill tolerance at all. These flowers won’t live in environments below 55 degrees Fahrenheit. Tender annuals are also known as true annuals. Among the tender annual are marigold, impatiens, verbena, coleus,and begonia.

Perennial flowers

Cold Tolerance Of Flowers According To Lifespan-Perennial flowers

Perennial flowers are advisable for those who make a profit in gardening. These flowers survive cold weather and will flourish again after a year of the cycle.

  • Hardy perennials: This variety of perennials is the flowers that can tolerate the most chill. Forty degrees Fahrenheit is still liveable for hardy perennials like coneflowers, black-eyed Susan, hollyhock, yarrow, and peony.
  • Half-hardy perennials: This second variety of perennials is much more tolerant to cold than half-hardy annuals. These will not survive in too chilly places but will do in balanced temperate areas. One of these is the nicotiana flower.
  • Tender perennials: Tender perennials are the most vulnerable to cold. They won’t survive frost and freeze. Hence, flowers should only be kept inside the house during the winter season. During this time, store it in a place with a room temperature of 50 to 55 degrees Fahrenheit to avoid death.

Cold Tolerance of Flowers According To Geographical Origin

We are sure that you are aware that flowers and plants have different geographical origins. Let us understand it more profoundly and identify the cold tolerance of flowers that can be seen in these places.

  • Tropical zone: The sensitive point for flowers in the tropical zone is 50 to 60 degrees Fahrenheit. Once the temperature dips below this point, the flower will definitely wither and die. Preferably, gardeners should plant tropical flowers after the frost surge or winter.
  • Temperate or subtropical zone: The flowers in these regions can tolerate chill but not too much. They may suffer if the temperature reaches the usual freezing point of 45 degrees Fahrenheit. Flowers like the famous maple leaf of Canada are included in this classification.
  • Polar zone: Glaciers and layers of ice surround the regions in the polar zone. For this reason, flowers that bloom in these areas are the most tolerant to cold. So, they are safe even if you leave them outdoors.

Examples of polar flowers are Jasmine, purple heather, and Linnea.

5 Effective Strategies To Prevent Frost and Freeze In Flowers

5 Effective Strategies To Prevent Frost and Freeze In Flowers

The last part of this blog will teach you how to protect your beloved flowers from cold weather, especially if they are planted outside your home.

  1. Bring your flower indoors: This strategy only applies to those flowers you place in a pot or small containers. Taking your flowers to a warm area is the most practical thing to do because of two reasons. First, it keeps your flowers safe. Second, it costs you no penny.
  2. Water your flowers: Did you know that wet soils trap more heat than dry ones? Put a generous amount of water if you believe cold weather will occur. However, please do not exaggerate it, considering that it might backfire. There is also a strategy called wall of water that most gardeners find compelling. Should you want to try it, do not hesitate!
  3. Cover the flowers with frost fabrics: Frost fabrics are also called frost blankets. As implied in the name, it is easy to decipher that these materials are made to cover plants or flowers.  Frost fabrics are available in synthetic and organic materials. They are recommended for flowers planted on farms or grounds, not in small areas.
  4. Add insulator: Insulators will keep the heat in the soil last longer. You can improvise this using mulch or hay. Note that you should remove it once the temperature already suits the flower.
  5. Create a burn barrel: A burn barrel is a metal container where you can start a fire and place it near your plants. This strategy is mainly used to provide heat to flowers. If you do this, ensure you will not burn the plants.


Forty-five degrees Fahrenheit is the standard answer to the question of how cold is too cold for flowers to be outside. However, this is not the benchmark freezing point for all since flowers have many types. Effects of cold weather may vary too based on their lifespan and origin.

Analyzing the type of flower you have may be challenging, but we are sure that it is worth it. Be patient and save your flowers from the chill using our effective strategies.

Leave a Comment