9 Tips That Will Keep Your Petunias Blooming All Season

If you have planted petunias this season, you may be wondering how to keep them blooming all season. There are numerous varieties of petunias and they all have very similar requirements for growth. They are fairly low-maintenance but with a little bit of care, the flowers will give a nonstop show of color. 

Unfortunately, in most hardiness zones petunias are annuals. This means you only have a short season to see their unique colorful blooms. If you live in zones 10 and 11, petunias are perennials, and they can bloom year-round. No matter what zone you live in, you want to ensure you do everything you can to see those amazing long-lasting flowers all season. 

So, what steps do you need to take to keep petunias blooming? Let’s dig into some helpful tips to keep petunias blooming all season long. 

Provide Enough Sunlight

No matter the variety of petunia you choose to grow, they all worship the sun. Petunias shouldn’t be planted in areas that receive less than 6 hours of sunlight per day. If you plant petunias in shady areas, more than the blooms will be affected. 

How much sunlight your petunias get per day is going to directly affect how often and how much they bloom. Plant in areas that receive 8 hours or more of sunlight per day. This will be your best chance at producing the most flowers. 

If petunias receive less than 6 hours of sunlight per day, flower production will be slow and plants can become scraggly. Planting in shade will create smaller plants that won’t reach their mature widths. You could end up with bare spots in your garden or containers because your petunias didn’t get as large as you expected. 

Provide Plenty of Water 

Proper watering is going to affect the plant overall. Petunias planted in containers or hanging baskets may require more frequent waterings. Give a good soaking once or twice a week to hanging baskets and containers. 

If you choose to plant directly into the ground give them a good soaking about once a week. Soaking the area thoroughly will encourage roots to grow deeper into the soil. Deeper roots allow petunias to be more drought tolerant. 

If petunias are watered lightly a few times a week, this creates plants with shallow roots. Shallow roots only absorb water that is available at the soil surface. They can’t access water that is lower in the soil during dryer periods. 

When watering hanging baskets and containers, you want to water until you see water flowing from the bottom of the container. This is a good indication that water is running through the entire container and soils are moist. 

Petunias planted in the ground may be a bit trickier to determine if they are watered enough. Check your soils often to ensure there is moisture an inch or so below the surface. If you begin to dig and you can’t find moisture in the first 2 inches, consider giving a thorough watering. 

Plant in Well-Draining Soil

Petunias need well-draining soils no matter where they are grown. If you choose to grow in containers or hanging baskets, ensure there are proper drainage holes. This will allow excess water to drain from the container and prevent soils from becoming soggy. 

If you have soils that are heavy in clay, water will have a hard time draining and this can cause problems for petunias. Adding compost can improve the drainage of all soil types. If you need to amend your soils, consider doing this before you plant your petunias. 

Petunias like soils that are basic in pH. They can tolerate anywhere from a 6 to a 7 but shouldn’t be planted in anything light or lower then this. If planted in the wrong pH, petunias will struggle to grow and become very stunted. 

If your soils are having a difficult time retaining moisture, mulch is a good option to help protect the soil surface. A one to two inch layer of mulch will give the soil some insulation from the sun. During hot and dry periods, mulch has proven to be beneficial at protecting the soil from erosion and moisture loss. 

Use Plenty of Fertilizer

Petunia are heavy feeders. They don’t need to be fertilized to survive but fertilizer will give you bigger and fuller plants. If you are looking to push your petunias to their maximum potential, consider fertilizing. A slow release fertilizer or organic fertilizer should be used before or during planting. 

Consider applying a liquid fertilizer every 2 weeks after planting to encourage more vigorous growth and more blooms. Water your petunias shortly after applying liquid fertilizers. This will help prevent fertilizer burn and allow the roots to absorb the fertilizer more rapidly. 

Cascading or spreading varieties require more frequent feedings than mounding varieties. Consider feed once a week to keep flowers blooming and to achieve larger plants. Containers and hanging baskets should be fertilized weekly as well. 

Prune When Necessary

Some varieties of petunias are self-cleaning. This means as the flowers fade and die, they drop from the plant and a new bloom can grow. Not all varieties of petunias are self-cleaning. If you are interested in self-cleaning petunias, do a little research before purchasing to ensure you are purchasing a self-cleaning variety. 

Certain varieties will require you to deadhead the spent blooms and trim the leggy stems. Pruning can begin as soon as you plant your petunias. If you purchase your petunias later in the season, they tend to be spidly. Once you’ve planted them, cut back spindly stems to encourage tighter growth.

During the season, cutting leggy stems and near spent blooms is beneficial. If spent blooms are not removed from the plant, the flowers will go to seed. Producing seed requires a lot of energy from the plant. If dead blooms are picked, the plant will put more focus on its blooms. 

Don’t Overcrowd 

Petunias can be a little greedy when it comes to space, especially the cascading varieties. Petunias can easily over power low growing flowers around them. Although they look great with companion plants such as snapdragons or silva, they definitely need plenty of room to grow. 

Be sure to give you petunias adequate space to grow, specifically in containers and hanging baskets. If there are too many plants planted into one container, nutrients and water will be used much quicker. 

Lack of nutrients and resources is going to affect how long and how much your petunias bloom. Be sure to choose a large, deep container if you are planting multiple plants in one container. And if planting into the soil, be sure to leave enough space between plants to allow for proper growth. 

Pay Attention to Temperatures

As much as we wish we could control the weather, we simply can not. When conditions are cool and cloudy, petunias will begin to slow their bloom production. Petunias love the hot summer heat and bright sunlight.

Unfortunately, there isn’t much we can do when conditions become cooler than normal. While you can buy cold tolerant petunias, most varieties won’t survive when temperatures drop too far below their normal growth habitat.

If your region is experiencing a period of cooler temperatures, you may see a decrease in your petunias flower production. Luckily, once temperatures begin to rise and the sun shines again, petunias will take off. 

Protect Them From Rabbits 

Petunias’ biggest enemies are rabbits. Controlling when and what rabbits eat is difficult to say the least. Petunias are a sweet treat for rabbits and they might pluck the blossoms off or pull whole plants if they have the chance. 

If you struggle to keep rabbits from eating your petunias, you’re not alone. Containers and hanging baskets are ideal for petunias because rabbits can’t reach them. If your petunias hang over the edge enough, rabbits may come nibble the ends. 

Keeping rabbits away from petunias planted in the ground is near impossible. There are many methods out there to help keep them away from petunias. It might be trial and error until you find a solution that works for you. 

Treat Diseases and Insects Early

Unfortunately, we can’t avoid diseases and insects when it comes to gardening. All plants are susceptible to infestations from time to time. The first step in controlling insects or diseases, is to first identify them. 

Some common insects that you can find on petunias are aphids, budworms and leaf miners. Each of these insects can cause extensive damage if left untreated. These insects can be controlled by insecticides you can purchase at your local nursery. 

Diseases are even more common than insects and will surely infect your petunias at some point during their lifetime. Some common diseases for petunias are crown rot, powdery mildew and gray mold. If infestation of a disease is minimal, pruning or pulling the infected plant may be enough to control the spread. If the disease has affected many plants, consider applying a fungicide from a local provider.