Petunia Flower Guide: How to Grow, Plant, Care for 5 Types of Petunias

Image Credit: Marisa04²³

Petunia Flower Facts and Uses (Including Types)

Petunias are versatile and popular flowers that appear in many gardens because they can fulfill so many purposes. Some of these include:

• Mixed Borders: Blend Petunias with perennials or other annuals to produce a varied and colorful appearance in your garden beds.
• Edging: Dwarf Petunias frequently serve as edging plants around garden beds. The burst of color that these plants provide around the bed can be striking.
• Groundcover: Groundcover or spreading Petunias work well to cover ground that is bare and provide beautiful color when they blossom.
• Containers: Hanging baskets, window boxes, or pots are all great places to plant Petunias, bringing color to balconies, patios, or other outdoor areas.
• Bedding Plants: Petunias can serve as mass plantings to take up significant parts of beds or to make striking borders.

5 Types of Petunias (and Petunia Color Varieties)

There are actually many different varieties of Petunias, and you can find them in just about every major color except for true blue flowers.

The different types of Petunias vary on the basis of care needs and appearance.² While there are many more than ten types, you can divide the types into five primary groups:

How Long Do Petunias Bloom? Are Petunias Perennials?

Generally, Petunias will bloom all summer long, but this can start earlier in the spring and last into the fall, depending on the range of temperatures.³ Once the temperatures dip into the 40s or below and frost comes, the blooming season will come to an end.

As an annual species, these beauties only last one season.

If you have an older Petunia plant, it is helpful to deadhead (take off blooms that have been spent) for them to keep blooming at an optimal level all summer long. Newer Petunia varieties do not need deadheading to keep flowering, but if you do it, the plants will maximize their blooming.

If you want your Petunia to seed itself, do not take the spent blooms off the plant. If you want the entire energy of the plant to power optimal levels of flowering (which is often your goal if you’re looking at this plant as an annual) then you will want to deadhead. If you have a leggy plant, trimming it back during the middle of summer can lead to healthy, fresh growth which generates more blossoms and more branching.

In the majority of climates, Petunias only last a single growing season as annuals.⁴ In some parts of the world, where the climate is warm year-round, you can get Petunias to self-seed and last as long as three years.

Are Petunias the Best Full-Sun Plants? Are Petunias Sun or Shade Plants?

Petunias do well in the sun as opposed to shade.⁵ However, if you live in a region with extreme levels of heat in the summer with harsh sunlight, the plant is likely to stop blooming temporarily. The majority of the Petunia varieties, across all planting zones, thrive in full sun which means six or more hours per day of direct sunlight.

When summertime comes, providing some partial shade during the afternoon, when the sunlight is the most intense, will provide optimal blooming and keep the plants fresh.

Knowing How To Identify Petunia Flowers in the Wild

Looking at the leaves, you will notice oval shapes with smooth edges.

Some Petunia varieties have sticky, fine hairs on the leaves. The leaves are sessile, which means that they do not have stems.

(Flower Image: Manfred Richter²⁴)

Looking at the flowers, you will see a funnel or trumpet shape with five petals that are either completely or partially joined together.

The most distinctive feature of the Petunia is its trumpet-shaped blossom.

Tips for Petunia Care

Understanding the best practices for planting your Petunias and maintaining them as time goes on will help you get the best results. Planting a garden involves a significant investment of time and money, so the more faithfully you keep up with upkeep for your Petunias, the more robust and beautiful results you will see from your blossoms.

Checking your flowers several times a week, if not once a day, can help you head off problems before they become too serious to address. Petunias are hardy flowers that do not need a lot of maintenance, making them popular among gardeners.

Fertilizer for Petunias: Knowing How Long It Takes To Grow Petunia Flowers

When you plant the Petunias, add a balanced fertilizer to provide extra feeding.⁶ If you have compost on hand, working that into the soil gives the plants an even better start.

Beginning in July, add a liquid fertilizer designed for flowering plants every two or three weeks. If you have one of the spreading types of Petunias, you may need to fertilize each week, so make sure you read the care instructions for your individual plant carefully.

Best Growing Zones and Conditions for Petunias

Petunias grow in a wide variety of climate zones: 1, 1A, 1B, 2, 2A, 3, 3A, 3B, 4-24, A1, A2, A3, H1, and H2. Their hardiness zones are 2-11.

Soil that is light and fertile, with adequate drainage, is best for Petunias.⁷ The soil type can vary as long as the area drains well.

In terms of soil pH, aim for a slightly acidic blend. The best time of year to plant Petunias comes after frost season; the soil needs to be workable and warm.

The best temperatures for Petunia plants fall between 60 and 75 degrees Fahrenheit during the day and 55 and 65 degrees Fahrenheit at night.

It is all right for the temperature to drop as low as 40 degrees Fahrenheit, but freezing temperatures and frost will harm and eventually kill the flowers. As far as humidity is concerned, low to moderate levels are ideal for Petunias.

Planting Tips for Petunia Flowers: How Far Apart To Plant

Ideally, you will plant your Petunias about a foot apart. This allows enough room for them to draw the nutrients they need from the soil without interference from nearby plants until the establishment of a hardy root system.

Hydration Is Key: Watering Needs for Petunia Seeds and Plants

Petunia plants require regular feeding and watering throughout the entire growing season, from the spring to the fall. Petunias prefer to have regular water but the soil cannot be soggy as that will lead to root rot.⁸ If you overwater, you will end up with fewer flowers per plant. Generally, beds should get one to two inches of water each week when it is not raining.

Some of the spreading Petunia types, as well as Petunias growing in pots or other containers, need water more frequently and at greater depth. Test the soil to keep it from drying out more than a couple of inches below the surface.

Picking the Right Neighbors: The Best Companion Plants for Growing Petunias

Companion planting is a terrific idea that helps provide benefits to all of the plants that they would not have received without the presence of their fellow species.

Petunias, for example, tend to draw insects that might do damage to other plants. If you plant Petunias with garden vegetables, the Petunias will entice bugs that might otherwise gnaw on your vegetables. The Petunias will suffer, but the vegetables are more likely to thrive.

(Image: ИринаЯ²⁰)

Petunias also bring helpful insects into your garden. Petunias produce nectar that pollinators, including bees, hummingbirds, and different types of butterflies, will come to gather. Companion plants also have a way of filling in space that weeds would otherwise grow in to fill. Here are some of the best plants to pair with Petunias:¹¹

• Salvia: Salvia grows above Petunias so that your growing area will have a contrast in terms of height. Salvia generates stalks with flowers that grow in yellow, white, purple, pink, and red. The blooming season comes from spring to fall, much like the blooming season that Petunias have. If you plant salvia behind Petunias, you will get color contrast throughout the growing season. You can also plant salvia in the middle of a hanging basket or container, surrounded by cascading Petunia varieties. Both plants will enjoy full exposure to the sun and moisture in the soil.
• Snapdragons: These are actually perennials that are most often grown as annuals. Their bloom looks like a dragon’s nose (hence the name). The stems develop towering blooms in red, pink, purple, white, and yellow. They can deal with partial shade, but they can also tolerate full exposure to the sun.⁹ Like Petunias, snapdragons thrive in soils that drain well. Petunias generally don’t grow higher than a foot, which makes them pair nicely with taller snapdragons, as they cover the lengthy snapdragon stems.
• Lantana: Both lantana and Petunias thrive in full sunlight. The flowers of lantana come in smaller clusters, contrasting nicely with the larger Petunia blooms. Both of these plants bring in a variety of pollinators, but they produce an odor that keeps deer and rabbits from coming in to take a bite, which means that lantana can keep Petunias from being eaten.
• African daisy: These blooms are large and bright, and they do best in full exposure to sunlight. You can grow African daisies in partial shade, but you will not get as many flowers as a result. You can grow them in the ground or in containers; if you choose a container, plant them in the middle to add contrast and height. Keep the soil evenly watered, just like you would for Petunias.
• Guara: Guara are also known as wand flowers, and they make a terrific option for new gardeners because of the low maintenance they require. They grow long stems, and pink blooms pop up along the stems that keep blooming. These also look beautiful behind your Petunias to add color and height. Your primary color options with guara are pink and white.
• Candytuft: Mounding varieties of Petunias could cover candytuft, which tends to grow lower. If you pair this with Petunias that cascade, you can have a rush of color in the garden. Candytuft is a subshrub which means it grows best in flower beds or landscapes, and it looks nice behind or between Petunias to provide a color contrast. Full sunlight works best for candytuft, making it a good match.¹⁰
• Lobelia: This spreading plant pairs best with mounding Petunia varieties. The flower blooms in lilac, pink, white, or purple with a small white dot in the middle of each flower. These flowers grow out and down over container edges and hanging baskets. During the late summer, lobelia can turn leggy, which is easy to fix with some pruning. You don’t have to deadhead lobelia, but if you do, it will keep a cleaner and neater look.
• Tomatoes: Petunias can do well next to vegetables and even help them out. Tomatoes benefit from the pollinators that come by to visit the Petunias. Whether you plant the Petunias and tomatoes in a garden or in containers, they both do well. Both plants thrive in the sun.
• Lettuce: Do you want to keep bugs out of your lettuce? Plant some Petunia nearby. The insects will chew on the Petunias and leave your lettuce alone. The blossoms also add some color to your vegetable garden and occupy the empty space that weeds might otherwise grow to fill.
• Strawberries: As a fruit plant, strawberries need pollinators and Petunias attract pollinators. These two plants thrive in the same soil moisture and sunlight conditions. They combine to provide ground cover and keep weeds from sprouting up.
• Blueberries: This fruit does best in six to eight hours of direct sunlight each day, just like Petunias. Both of these plants enjoy moist soil, and Petunias cover the ground to keep moisture in the soil longer for the blueberries. The Petunias will also draw insects away from the blueberry bushes.
• Garden peas: If you want to add some visual appeal to your vegetable garden, pair Petunias with your garden peas. The pea plants are stringy and green, without much to draw the eye. The peas taste delicious, but you cannot see flavor. The aphids that would normally come after your peas will stop and chew on the Petunias, and the Petunias will cover the ground that the pea plants leave behind at the end of their life cycles.
• Dracaena spike: Spike does not generate any flowers; instead, you get narrow, long leaves that look like swords. Full sunlight is best for spikes, as is soil that drains quickly. If you plant these in the middle of pots, you get a tall, narrow plant in the middle, which you can then surround with Petunias. In beds, spikes can serve as a dramatic backdrop to shorter flowers that provide color.
• Fountain grass: This is a decorative grass that grows purple, copper, or pink flower spikes on top. They do best in full exposure to the sun, just like Petunias. The tall grass stems provide a nice contrast with the colorful Petunia blossoms below.
• Periwinkle: Periwinkle produces violet-blue flowers as well as some white flowers. The leaves are leathery and glossy green. If you plant mounding Petunias in the center of containers, surrounded by periwinkle to drape down the sides, you will have an attractive hanging basket. Periwinkle, also known as vinca, can turn invasive, so putting it in a container or hanging basket might be preferable to letting it loose in your garden.
• Celosia spicada: This annual plant spreads upright and has impressive blooms that can get as high as four feet, or even higher. Their blooms look like bottle brushes, and they stay brightly colored throughout the growing season. Petunias can cover up the stems, adding color from the ground up. Like Petunias, Celosia spicada does best in full exposure to sunlight.
• Geraniums: This flowering plant also comes in a wide variety of colors such as purple, orange, pink, red, and white. They grow well in containers as well as flower beds. The stalks are long and dark green, with colorful blossoms popping up on top. Petunias pair well as they will bloom slightly lower, and both plants enjoy full sunlight.
• Dusty Miller: These plants are popular sources of filler in beds, with their silvery leaves decked with green. Their leaves contrast nicely with the purer green of the Petunia. Dusty Miller does well in dry conditions and can thrive in the heat. During the middle of the summer, it can produce yellow blossoms, but these are too small to notice. Like Petunias, Dusty Miller will do better if you prune in the middle of the summer.

What plants should you avoid pairing with Petunias? Plants that would compete for the same nutrients or that need different growing environments.

In the vegetable garden, do not put Petunias near zucchini, squash, or corn, and do not plant Petunias near cactus or sunflowers.

Knowing When To Plant Petunia Flowers for the Best Yield

The best time of year to plant your Petunia comes after the last date of frost in your part of the world. In the majority of cases, late spring and early summer are the best times. You will want to wait until soil temperatures reach at least 60 degrees Fahrenheit because damp or cold soil will not be hospitable to the plants.

If you live in a warmer part of the world, you can also plant Petunias during the fall to bring color during the winter but you will want to live where temperatures do not go below freezing to do this.

Understanding How To Stop Petunia Flower Disease

One of the most common diseases that strike Petunias is botrytis blight. This fungal ailment leads to brown or gray spots on flowers and leaves.

If this shows up in your flower bed, take the infected parts of the plant out and work to boost air circulation. Treat the plant with a fungicide.

Going forward, check your Petunias frequently for signs of damage or stress. If you take care of these issues promptly, your Petunias are much more likely to thrive and produce a gorgeous blossom display.

Common Pests of the Petunia Flower (and Natural Pest Control for Petunia Flower)

As with just about every plant in the natural world, Petunias have some natural pests that will bother them.¹²

These include slugs, flea beetles, snails, and aphids that enjoy chomping on the leaves and stems. The easiest way to get the pests off the Petunias is to use a hose to deliver a stiff jet of water. If the pests have arrived in such numbers that flowering is suffering, it is possible to use insecticides.

If you live in an especially rainy climate, you may find that your Petunia struggles with fungal diseases like gray mold.

If you reside in a damper part of the country, choose a Petunia variety that can handle higher levels of moisture.

Starting Your Petunia Plant and Petunia Seedlings: Should You Plant Petunias in Pots?

There’s nothing wrong with starting your Petunia plant in a pot. Any all-purpose potting mix that has a quality reputation should work well. You can space Petunias a little closer to each other when you are using a pot rather than a flower bed, and the end result will be a fuller look as far as blossoms.

However, remember to keep your maximum at three plants for containers that are a foot deep and wide. Make sure the pot has enough drainage. You can use pots from any material, but if the color is lighter, the roots are less likely to overheat.

(Image: Dandy1022²¹)

Choose a container that is large enough to host the Petunias once they reach full size so that you will not have to re-pot them. If you have to do this and end up disturbing the blooming process.

Growing a Petunia Flower From a Seed or Seedling

Most gardeners buy their Petunia plants from a local nursery when they are young. However, growing Petunias from seed can be an exciting challenge, particularly if you are trying to get one specific variety or color, such as purple flowers or certain types of white flowers.¹³ Start the seeds no fewer than 10 to 12 weeks earlier than the last projected frost date for your zone, and follow these steps:

1. Add water to a seed-starting mix until it is moist. Spread the small Petunia seeds across the mix and press them down gently. However, leave them at least partially exposed as they cannot germinate without light.
2. Place clear plastic over the container, and set it in a place that is warm but does not have exposure to direct sunlight. After a week to 10 days, seedlings should be visible.
3. Take the plastic off after you see the new seedlings.
4. Once the seedlings have developed three actual leaves, you can move them into their own individual pots until they are prepared for outdoor transplantation.

Understanding How To Propagate Petunias

Stem cuttings are the best way to propagate Petunias. If a gardener wants to preserve a certain variety, such as one that most nurseries in their area do not sell, then stem cuttings are the way to go. After this, you can cultivate your cuttings inside during the winter and then plant them outside after springtime banishes the frost for another year. All you have to do is pick the cutting from one of your healthy plants in the fall before the first frost. Here are the steps:

1. Trim a healthy part of the stem that is about six inches long. Look for a stem that is supple and green, rather than a woody, older stem.
2. Take the foliage off the bottom half of the cut stem.
3. Stick the cut end into a container of rooting hormone.
4. Add some moistened, soil-free potting mix to a small growing container.
5. Plant the stem inside this mixture, and set the container in indirect, bright light.
6. Ensure that the potting mix remains moist, and wait for root growth to take place usually within 2 to 5 weeks.

Troubleshooting, Including Issues With Your Petunia Leaves

Petunias are generally easy to maintain and produce beautiful blooms on a regular basis. However, there are some issues that can arise.¹⁴ With these tips, you can keep the problems from getting out of hand.

• Leggy Stems: If your Petunia stems get too leggy, all you have to do is deadhead your flowers on a regular basis and pinch the stems back. If your Petunias still do not fill out, you also can prune each stem back to about three inches long. Once the plant grows back, you should see less leggy progression.
• Wilted Leaves or Flowers: Blossoms and leaves will wilt for a variety of reasons, but most of the time they have to do with water, either not enough or too much. Test the soil, and add water if the soil is not damp. If you feel moist soil, do not water as often.

Pruning your Petunia plants can be an important step in the planting process. If you pinch the stems back at this phase, you can end up with more branching and a fuller Petunia plant. If the seedling is stocky and short, pinch no more than an inch. With a more gangly seeding, you can pinch back half of the stem.

If you have a difficult time keeping your soil cool and damp, adding mulch in a layer around the Petunia Flower can help the soil retain water for a longer period of time.

Frequently Asked Questions About Petunia Flower Types