How Long Will My Petunias Actually Last?

Petunias are a favorite among gardeners for their lasting blooms and easygoing care. They bring a flood of color to any space all season or year long. With the proper sunlight, water, and soil conditions, petunias will reward you with colorful displays of blooms. 

Petunias are a tender perennial, but for most hardiness zones, they are treated as an annual. That being said, petunias will behave differently if grown as a perennial or an annual. No matter how they are grown, they all produce beautiful lasting flowers. 

So how long will my petunias actually last? In this article, we will review how long you can expect your petunias to last and ways to help extend their longevity. 

The Short Answer

Petunias are a beautiful perennial or annual that produce continuous floods of colorful blooms. Depending on where you live you may be able to grow petunias as perennials. This is great because your petunias will continue to bloom for many months.

Petunias grown as perennials may bloom for anywhere from 18 to 24 months before they fizzle out. If you live in cooler hardiness zones then growing petunias as annuals, they will last from spring to the first frost in the fall. Petunias are very sensitive to frost and will not last long after being nipped by the frost.

If you provide the proper care, petunias will thank you with endless blooms and lush foliage. Although they are noted for being relatively low-maintenance, a little bit of care will go a long way. Proper sunlight, water, nutrients and soil are key to lasting petunias.

The Long Answer 

Petunias will grow as a perennial if you live in hardiness zones 10 and 11. You can expect blooms on your petunia plants all year long. You will have to do some maintenance to keep them looking clean and blooming continuously. 

If you live in areas where petunias only grow for one season, you might wonder if you can extend their life a bit longer. If you live in cooler regions, you will do anything to extend the life of your plants.

There are a few methods to help extend the bloom window and keep your petunias thriving even after the first frost. These methods may require a bit more work on your end, but it will be well worth it when your petunias bloom late into fall. 

Ways to Extend The Life Of Petunias

You can do several different things to extend your petunias’ lifespan, including proper care. Let’s take a deeper look at how to ensure they live long lives with full blooms.

Protect From Frost 

Petunias will die if they aren’t protected from frost and colder conditions. There are methods to keep your petunias lasting after the first couple of frosts. If you have petunias in hanging baskets or containers, bring them indoors to your garage or home. 

Place your hanging baskets or containers back outdoors if temperatures are warmer during the day. This will extend their life for several weeks. In the fall, temperatures will be cooler at night but warm during the day.

If you are growing petunias in a garden or landscape, consider throwing a floating row cover, an old sheet, or a frost blanket over them to protect them. This will extend their life just a bit longer, possibly into late fall. There will be a point where temperatures are just too cold, and petunias can no longer be protected from the elements. 

Proper Sunlight 

Petunias need plenty of sun to thrive and produce flowers. If they are given inadequate lighting, your petunias will not last long. They need a minimum of 6 hours of sunlight per day to grow. For best flowering, plant in 8 hours or more of sunlight per day. 

Petunias will be stunted, leggy, or may die when planted in the shade. If you can, we recommend avoiding planting petunias in the shade. Petunias will reward you with continuous color when planted in proper sunlight. 

Proper Watering 

Petunias don’t have the highest water demands, but they must be watered regularly. Petunias benefit from a good soaking one to three times a week. When planting petunias in containers or hanging baskets, they will need more water than petunias planted in the ground. Consider watering containers 2 to 3 times a week, depending on the weather. 

A good soaking will promote deep roots and help make petunias more drought-tolerant. Petunias with shallow roots may die or become stunted when periods of dry soils are present. Slow, gradual irrigation with a soaker hose or drip irrigation is ideal, as this allows the soil to absorb moisture.

Proper Soil 

Petunias will not grow well in soggy soils. Plants will become stunted; the leaves will become yellow, and over time, they will die. Choose proper potting soil if you are growing petunias in containers. Most soils sold in a garden center are perfect and are designed for containers. 

Fertilizer 

Petunias benefit from regular doses of fertilizer to help promote proper growth. Consider adding a slow-release fertilizer to prevent the nutrients from leaching from the soil. Slow-release fertilizers are a great option because they don’t burn the plant.

You can add liquid fertilizer if you choose. Remember that liquid fertilizers leach from soils very quickly, and strong chemical variations of liquid fertilizer can cause nutrient burn to your plant; use only diluted liquid fertilizers.

No matter what method you choose, you will need to fertilize often. Slow-release fertilizers should be applied monthly per the manufacturer’s recommendations, and diluted liquid formulations should be applied weekly. 

Deadheading 

Some varieties of petunias are self-cleaning, meaning they will drop their spent flowers from the plant. Other varieties require you to remove the spent blooms so they don’t go to seed. If plants go to seed, they will produce fewer blooms. 

Deadheading should be done weekly to keep petunias clean and blooming. Simply identify the fades, wilting, or browning flowers and pinch or cut the base and petals. Be sure to remove the base of the flower, as this is where the seeds are produced. 

Pruning 

While pruning isn’t necessary for petunias to grow well, it is recommended. Pruning leggy stems will keep plants in compact mounds or from getting too long and stringy. In addition, leggy stems are just not appealing and tend to produce few flowers. 

Cut leggy stems 3 to 4 inches every week or two to keep plants neat and clean. Trailing varieties benefit from regular pruning to keep the plant from getting long and stringy. If mounding varieties are pruned regularly, they will stay compact.  Pruning will also increase bloom production as well.