The 9 Best Annuals for Container Gardens

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If you plan to grow a container garden on your porch, balcony or patio, you might love the idea of having a beautiful splash of colors throughout the spring and summer. While some people like keeping the same plants alive every year, annual gardens are a fun, easy and commitment-free way to add an array of colors to your space.

Overall, these plants are less expensive and require less maintenance than perennials, and if you do find an annual to be too difficult to care for, you don't need to feel guilty about giving up on it and trying a different plant. When your annuals naturally die off, just move your growing containers out to the garage or a storage shed until next spring or plant some winter-friendly annuals to enjoy blooms all winter as well.

Gardening Tips for a Container Garden

Container gardens are unique in that they allow you to grow a wide array of plants with widely differing needs as long as those sharing a planter also have similar needs. When it comes to soil requirements, most plants recommended as container plants do just fine with a basic potting soil that drains well and is rich in organic matter. Similarly, most of these plants do well with a bimonthly or monthly dose of water-soluble, 10-10-10 fertilizer.

While most container-grown plants require regular waterings to keep the soil moist but not soggy, it is still a good idea to keep drought-tolerant plants and water-loving plants in different containers. Also, remember that some plants require a lot more space than others, so be sure to research a plant's space requirements before you plant something in small pots that would do better in large containers instead.

Selecting the right plants to go together in a single container isn't just a matter of finding a few varieties with similar care requirements. It also involves choosing species that will look good together. While you might be inclined to choose an array of beautiful annual flowers to add to your container garden, just selecting a bunch of pretty flowers may leave you with a garden that looks too busy since your stunning blooms may end up competing with one another. If you want to have the best garden of annuals in your neighborhood, you'll need to find a good balance among your container plants.

A good rule of thumb when mixing plants in a single container is to try to create a good combination of eye-catching thrillers and some fillers to complement but not compete with these standout plants. You may also want to grow some creeping plants to tumble over the side of the container, creating a little more visual interest than your hanging baskets and window boxes may have on their own.

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1. Petunia

Petunias (Petunia × atkinsiana) have been so popular for so long that some people consider them to be "granny flowers," but there are good reasons for their widespread appearance in gardens for over 100 years — they're easy to grow and beautiful. Petunias usually grow in trumpet shapes and are available in a wide range of colors, including pink, purple, black, blue, yellow, orange, red and white. They are usually striped or solid but sometimes have color gradients, or the tips of the petals may have contrasting colors only on the edges. If you don't like the trumpet look of classic petunia flowers, don't immediately bypass them — just look for the pirouette petunia varieties that have ruffled petals that look more like carnations.

Petunias are annuals in most areas but can survive as perennials in zones 9 to 11. They should be protected from intense afternoon sun in those regions. These flowers can survive in partial shade but will produce more blooms if grown in full sun as long as they aren't harmed by overly warm direct sunlight. Petunias are water lovers and are great for inexperienced gardeners because they do just fine when a large amount of water is splashed all over them. Deadhead flowers to encourage more blooms. To keep the plants bushy, pinch back stems when they start appearing too leggy.

2. Walleriana and New Guinea Impatiens

Behind petunias, some of the most popular flowers commonly grown in containers are impatiens, with the most common species being the walleriana variety (​Impatiens walleriana​). These small, shrubby, flowering bushes are perennials in areas without frost, and other growers can keep them alive throughout the year by taking them indoors during the winter, though most gardeners grow them as annuals. The plants tend to grow around 8 to 24 inches tall, with their deep-green leaves covered in flat flowers in white, red, pink, peach, purple and coral.

One great thing about impatiens is that unlike most flowers, they thrive in shady areas, allowing you to add a bright splash of color in the dark corners of your porch or balcony. If you love the look of these flowers but want to grow them in a sunnier area, look for their cousin, New Guinea impatiens (​Impatiens hawkeri​), which have the added benefit of more colorful leaves adorned with splashes of yellow or red. Keep in mind that even New Guinea impatiens should be protected from direct sunlight during the peak midday heat.

Regardless of whether you're growing walleriana or New Guinea impatiens, these flowers do not do well with drought, so do not let the soil dry out. Mulching can help maintain even moisture levels.

3. Million Bells

These cute flowers look like small petunias and are prolific bloomers, growing flowers in pastels and bold shades of red, orange, white, pink, yellow, blue and violet. Depending on the variety, they can make great fillers or spillers because some are bushy plants growing to about 8 inches, while others tend to creep along the ground, happily trailing outside the edge of a planter box or basket. Million bells (Calibrachoa) are annuals in most of the country, but they are perennial in zones 9 to 11, and in warm, humid areas, such as Florida, they survive much better in the heat than petunias.

Although million bells like full sun, they will do better in hot areas if they are protected from harsh afternoon sun. To keep the more bushlike flowers from getting too leggy, pinch off the top of the plants.

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4. Verbena

Verbena (​Verbena officinali​s) is famous for cascading over the sides of pots and baskets with miniature clusters of blooms that come in light and bright shades of pink, purple, coral, red and white. These great accent plants are particularly low-maintenance and heat tolerant, making them a great addition to just about any container garden. As a bonus, verbena will attract all kinds of pollinators, including hummingbirds, butterflies and bees.

Make sure your verbena plants get full sun. These plants are drought tolerant but don't like excess moisture, so it's often best to ensure the soil dries out before you water again. While verbena doesn't require deadheading, you may need to trim back the plants to prevent them from taking over containers. Trimming will also result in your plants growing bushier and developing more flowers.

5. Browallia

Browallia (​Browallia speciosa​) is best known for its bright-blue blooms that grow in a star shape, though it also comes in purple or white varieties. With its striking appearance and mounded shape, this flower can play any role in a container, serving as a stand-out addition, filler or a spillover enhancement along the edge. While normally grown as an annual, these plants do well in partial or full shade, so they can be grown as a perennial if brought indoors and grown as houseplants during the winter.

Browallia should be kept out of direct sunlight, which will burn its leaves. Take care not to allow the soil to dry out, as this plant does not do well in drought conditions. Pinch back the plants to keep foliage bushy and to encourage more blooms.

6. Cape Daisy

Are you looking for a particularly striking flower to stand out from the rest of the plants in your container garden but want something that's still hardy and easy to grow? Look no further than the cape daisy (​Osteospermum ecklonis​). These low-maintenance beauties grow an impressive 2 feet tall, sprouting white flowers about 3 or 4 inches wide with black and bronze colors around the center. They are great for cutting and displaying in vases and bouquets, but if you leave them on the plant, they attract pollinators, like birds, butterflies and bees.

Plant cape daisies in full sun approximately 1 foot apart. Let the soil dry a little between waterings. Once established, these daisies are drought tolerant and very heat tolerant, but to maximize blooms, keep watering on a regular schedule during summer. Deadhead flowers until the end of the season, at which point you may want to leave the last set of dead flowers to attract birds to your yard if you enjoy bird watching.

7. Sweet Potato Vine

An ideal spiller plant for any large container, sweet potato vines (​Ipomoea batatas​) are notoriously hardy and can survive in full sun or full shade as long as they have moist, well-drained soil. True to its name, the plant does grow sweet potatoes, but these are low quality and should not be eaten. The vines come in a wide array of colors, including chartreuse, purple, copper or even black shades.

Because each vine grows up to 10 inches long, it's important to make sure to grow these plants in containers large enough to give them room to fully grow or be prepared to trim back the vegetation regularly. Keep them out of the hot afternoon sun if you live somewhere particularly warm, such as zone 10 or 11, but otherwise, these plants enjoy full sun. Do not fertilize them or it can cause the plants to overtake your container.

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8. Geranium

There are so many geranium (Perargonium) species that it can be difficult to describe them all, but they're all great additions to a container garden. They grow flowers in red, pink, orange, white, purple and more. A few notable types include:

  • The classic zonal geraniums are the ones most people envision when they hear the name. These feature rounded leaves with clumps of flowers growing on long stalks.

  • Ivy-leaved geraniums are great for hanging baskets because the long stems of the flowers often hang all the way down to the ground or over the sides of the basket.

  • Regal geraniums have large and sometimes patterned flowers that grow in clusters.
    Their leaves often have a pleasant scent, making them a good choice for any container garden grown close to a home's doors or windows.

  • For a particularly aromatic option, look for scented-leaf geraniums that smell like other plants, including pineapple, orange, lemon, rose and peppermint.

Overall, most geraniums prefer cool nights and warm days in full sun, but they prefer shade from harsh afternoon sun. Although you can grow them as annuals, you may keep them alive year-round if you take them indoors before cold weather begins and keep them near a sunny window.

Geraniums are fairly easy to grow but take care not to overwater them because they are prone to a number of diseases and pests, many of which thrive in overly wet conditions. To keep plants bushy, pinch back regularly and deadhead flowers to increase productivity.

9. Caladium

Sometimes, it's a good idea to fill in your containers with something other than flowers. Caladiums (​Caladium bicolor​) are a great option, with their colorful, heart-shaped, spotted and striped leaves available in greens, yellows, pinks, reds and whites. While most varieties grow between 2 and 3 feet tall, there are also dwarf varieties about 1 foot tall that are preferable for smaller containers.

These houseplants are a great choice to brighten shady spots on your porch or balcony, as they love partial and full shade. That being said, some newer varieties do just fine in full sun, so you don't necessarily need to count them out if your container garden is in a sunny spot. The caladium is native to tropical regions, so it needs a fair amount of humidity and cannot handle cold weather, even at night. For this reason, it prefers very moist though still not soggy soil, so be sure to plant them with other water-loving plants.

references

Jill Harness is a blogger with experience covering architecture, design and decor trends from around the globe. As she lives in what would politely be called a "fixer upper," she is particularly interested in writing about DIY projects and repairs. Most of her home design writing can be found at www.homesandhues.com. You can find out more about Jill's experience and learn how to contact her through her website, www.jillharness.com.

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