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Until a few years ago, if you wanted to grow annual flowers, your choices were limited to geraniums, impatiens, marigolds and red salvia. But today, most greenhouses offer an eyecatching array of choices. Whether youre planting a windowbox, lining your sidewalk, or spicing up your perennial garden, heres how to make the most of whats available.
Strictly speaking, an annual plant is one that completes its growing cycle (grows from seed, flowers and produces seed) in the course of a single growing season. In other words, annuals pack a lot of living into a short span of time.
But beyond this simple definition, there is an even wider range of plants that we treat as annuals. Some, such as impatiens, heliotrope and tuberous begonias, are actually tender or “half-hardy” perennials that cant survive even a light frost. On the other hand, some annuals, such as pansies and ornamental cabbage, are extremely cold-hardy and can withstand freezing temperatures quite well.
One of the best things about annuals is their incredible diversity and versatility. Using them allows you to compose really exciting combinations of color, form and texture that will last all season long. Colors range from bright midsummer favorites such as zinnias and Mexican sunflowers, to the subtler pastel shades of stock or lavatera.
You can also select annuals for your garden based on characteristics other than flower color. There are annuals that are tall, medium, short or climbing; ones that prefer either full sun or partial shade; and those with special virtues, such as delightful fragrance (stock, mignonette, nicotiana) or attractive foliage (caladium, coleus, dusty miller).
Annual flowers and plants are a wonderful addition to any garden With their colorful blooms and fast growth, they provide almost instant gratification and pop of color. However, annuals require some special care to enable them to thrive throughout the season. Follow these tips to successfully grow annuals in your garden
What are Annuals?
Annuals are plants that complete their entire life cycle – germination, growth, flowering, seed production and death – within a single growing season. This makes them different from perennials and biennials which live for multiple years.
True annuals only live for one year. Some common examples are zinnias, marigolds, petunias, cosmos, sunflowers and morning glories. However, some perennials are also treated as annuals because they cannot withstand cold winter temperatures in certain climates. These include impatiens, begonias, coleus, and sage.
One of the biggest benefits of annuals is the wide variety of colors, heights, and forms available. You can find annuals as tall as sunflowers or as low as sweet alyssum. They come in every color of the rainbow, allowing creativity in garden design.
When to Plant Annuals
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Hardy annuals can tolerate some frost and light freezes Direct sow after the last spring frost date They can also be started indoors 6-8 weeks before last frost and transplanted outside about 4 weeks before last frost. Examples calendula, nigella, bachelor buttons, larkspur.
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Half-hardy annuals need warm soil and air temperatures. Plant outdoors 1-2 weeks after average last frost date. Start seeds indoors 4-6 weeks before last frost. Examples: zinnias, cosmos, nicotiana.
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Tender annuals are very sensitive to cold. Direct sow outdoors only after soil has warmed and all danger of frost has passed. Start seeds indoors 6-8 weeks before last expected frost. Examples: marigolds, gomphrena, sunflowers.
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In warm climates (Zone 9-11), annuals can be planted in fall or winter for an early spring show. Protect from frost with covers.
How to Plant Annuals
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Prepare soil by mixing in 2-3 inches of compost or other organic material to improve drainage and nutrients. Rake area smooth.
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For transplants, gently loosen root ball, set plant in hole slightly deeper than it was growing in the pot. Firm soil around plant. Space according to mature plant width.
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For direct sowing, plant seeds at depth of 2-3X their size. Cover and firm soil. Thin seedlings.
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Water thoroughly after planting. Add 2-3 inch layer of mulch to retain moisture.
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Fertilize at planting with slow release organic fertilizer. Avoid over-fertilizing.
Caring for Annuals
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Water: Most annuals need moist soil. Water at base of plants, avoid wetting leaves. Water when top 1 inch of soil is dry. Provide 1-1.5 inches per week from rain or watering.
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Fertilizer: If planted in amended soil, annuals typically won’t need additional fertilizer. Those in containers need light weekly feeding.
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Deadheading: Remove spent blooms to promote continuous flowering. Pinch back tall annuals to encourage bushy growth.
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Staking: Tall floppy annuals like cosmos may need staking to support stems. Insert stakes at time of planting.
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Pests & Disease: Inspect regularly and treat any issues promptly. Common problems include aphids, caterpillars, powdery mildew, botrytis. Good air circulation helps.
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End of Season: Protect from frost or move containers indoors. After frost blackens plants, pull out old plants and compost or discard.
Choosing Annuals for Your Garden
When selecting annuals, consider their appearance, growing requirements and your garden conditions:
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Sun or shade: Choose annuals suited to the sunlight patterns in your garden. Full sun lovers include marigolds, zinnias, petunias. For shade try impatiens, coleus, begonias.
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Height: Select short annuals for edging beds, medium height for mid-border, tall kinds as focal points. Combine heights for texture.
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Color: Annuals offer every color. Choose a single color for bold mass planting, or combine colors for dazzling effects. Use colors to create cohesion.
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Fragrance: Scented annuals like nicotiana, stock, mignonette and scented geraniums add fragrance to the garden.
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Hardiness: Check plant tags for indicated hardiness zone and choose accordingly. Hardy annuals tolerate cooler conditions.
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Uses: Consider if you want cut flowers, container plantings or edible flowers like nasturtiums and calendula.
With the right selection and care, annuals will thrive in your garden from spring until frost, providing months of bright, colorful blooms. A bit of maintenance will go a long way in keeping annuals looking their best all season long.
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Gardener’s Supply is in business to spread the joys and rewards of gardening, because gardening nourishes the body, elevates the spirit, builds community, and makes the world a better place. Visit our About Us page to learn more!
Last updated: March 27, 2025 | 14 min read
Until a few years ago, if you wanted to grow annual flowers, your choices were limited to geraniums, impatiens, marigolds and red salvia. But today, most greenhouses offer an eyecatching array of choices. Whether youre planting a windowbox, lining your sidewalk, or spicing up your perennial garden, heres how to make the most of whats available.
Strictly speaking, an annual plant is one that completes its growing cycle (grows from seed, flowers and produces seed) in the course of a single growing season. In other words, annuals pack a lot of living into a short span of time.
But beyond this simple definition, there is an even wider range of plants that we treat as annuals. Some, such as impatiens, heliotrope and tuberous begonias, are actually tender or “half-hardy” perennials that cant survive even a light frost. On the other hand, some annuals, such as pansies and ornamental cabbage, are extremely cold-hardy and can withstand freezing temperatures quite well.
One of the best things about annuals is their incredible diversity and versatility. Using them allows you to compose really exciting combinations of color, form and texture that will last all season long. Colors range from bright midsummer favorites such as zinnias and Mexican sunflowers, to the subtler pastel shades of stock or lavatera.
You can also select annuals for your garden based on characteristics other than flower color. There are annuals that are tall, medium, short or climbing; ones that prefer either full sun or partial shade; and those with special virtues, such as delightful fragrance (stock, mignonette, nicotiana) or attractive foliage (caladium, coleus, dusty miller).
Perennials Grown as Annuals
A tender perennial is one that wont survive the winter in your climate. Many gardeners simply treat these plants as annuals, enjoying them for one season and letting them die in the fall. Other people move plants inside at the onset of cold weather: treating them as houseplants over the winter; taking cuttings and starting new plants; or simply digging up and storing part of the plant (usually the roots or bulblike structures) indoors for replanting the following year.
Examples of perennials that are commonly grown as annuals include the more tender flowering sages (Salvia coccinea, S. patens, S. splendens, etc.), verbenas, and hyssop (Agastache spp.). Geraniums and scented geraniums (Pelargonium spp.) can be grown outdoors either in beds or pots during the summer, then brought indoors at the end of the season: to bloom in pots, to store in darkness for replanting, or to use as cuttings for new plants. Petunias, coleus, and sweet-alyssum (Lobularia maritima) are other plants that can be overwintered in pots and replanted the following year.
If you have a sunspace or attached greenhouse that receives plenty of winter sunlight and doesnt get too cold at night, you might try growing some of the interesting “annuals” that in their native habitats are actually perennial shrubs and trees. For example, if given year-round protection, fuschias grow rapidly, reach anywhere from 18 inches to 12 feet or more, and produce their beautiful pendulous blossoms in shades of red, purple, and white nearly all winter long. Brugmansia, or angels-trumpet, can grow to 15 feet tall in greenhouse cultivation. Its trumpet-shaped flowers are fragrant and beautiful, but dont grow it in the house if you have small children; the plants are extremely poisonous.
Flowering plants that grow from tender bulbs, such as dahlias, gladioluses and cannas, are often planted as annual flowers in cutting gardens or mixed ornamental borders. They, too, are tender perennials, and most varieties wont survive the winter outdoors in most of North America. However, its easy to dig up these bulbs at the end of the growing season and store them indoors for replanting the following year.
Annual Flower Care | How To Grow Annuals | Caring for Annual Flowers | Summer Flower Gardening Tips
FAQ
How to keep annuals blooming all summer?
- Keep the watering consistent and the soil evenly moist. …
- Deadhead flowers on annuals that make seeds. …
- Prune the long stems regularly. …
- Annuals need fertilizer. …
- Know when it’s time to say goodbye.
How often should I water my annual flowers?
Any plant grown in a container will dry out quickly, and annuals, with their shallow roots, will need water nearly every day. Check the top inch of soil – if it feels dry to the touch, water. You may need to water more than once a day in the extreme heat of summer.
Do annuals need deadheading?
… marigolds, snapdragons, and petunias, deadheading can be done as frequently as you like to keep the plants looking fresh and to prolong their flowering periodJun 26, 2024