A garden just isn't a garden without flowers! Whether planted in a grand border, a small bed by your backdoor or in pots on your deck, flowering plants add immeasurably to our enjoyment of the garden. Even if you are a die-hard vegetable gardener, adding flowers alongside your tomatoes and squash will not only add beauty, but will attract the pollinators and beneficial insects so important to a thriving garden.
Annuals are among the most gratifying flowers to grow because, once they start to flower, many keep it up non-stop for the rest of the season. And because you plant them anew every spring, annual flowers are great for trying out new plants and new color combinations.
So what exactly is an annual? Botanically speaking, it's a plant that, in one growing season, will flower, set seed and die. And many of the plants we call annuals are indeed true annuals. Some of the plants we grow as annuals, such as snapdragons, petunias and impatiens, are actually frost-sensitive perennials that we just grow as annual flowers because they aren't hardy enough to make it through our winters. The true annuals are divided into hardy and tender annuals. Hardy annuals, such as larkspur, can take some frost and can be sown in the spring as soon as the ground can be worked. But many annuals such as nasturtiums and cosmos need to wait until the last frost date has passed before they go in the ground.
Many annuals can be be started early from seed indoors, then transplanted to the garden for earlier bloom. Others grow quickly enough that they can be sown directly where they are to grow in the garden. Some annuals, such as poppies, resent transplanting and do best if they are direct seeded.
'Carpet of Snow' Alyssum (Lobularia maritima) - Also called sweet alyssum, this hardy annual forms a dense carpet of fine textured foliage that is covered with masses of small, white, fragrant flowers that are great for attracting beneficial insects. Although you can start it from seed indoors 5 to 6 weeks before your last frost, you can also sprinkle the seeds outdoors where they'll grow as early as a few weeks before the last frost. Press lightly into the soil, then water. In just 5 or 6 weeks, these speedy growers will be blooming. After the first flush of bloom, cut plants back by about half for a new round of flowers. You can also make repeat sowings throughout the summer, as late as early August, to keep up the show into the fall.
'Choice Tall Mixed' Bachelor' Buttons (Centaurea) - Another hardy annual that can be sown outdoors where it is to grow in early spring, this old-fashioned favorite has a mix of blue, pink, white and wine-red flowers on a 2-3' tall plant. Also called Corn Flower, its a perfect addition to a cottage garden, makes a great cut flower and attracts beneficial insects. In mild winter areas, you can sow the seeds in mid-fall for bloom through until spring.
'Sensation Mix' Cosmos (Cosmos bipinnatus) - With 4", saucer-shaped, single blossoms in shades of pink with yellow centers and delicate, ferny foliage, cosmos adds a graceful note to the garden. Easy to grow, the seeds can be sown directly in the ground around the last frost date. Plant seeds about 1/8" deep and thin seedlings to stand about 12-15" apart. 'Sensation Mix' grows about 4' tall and is great for adding height to the garden.
'Semi-Double Fancy Mix' Calendula (Calendula officinalis) - The bright sunny flowers of calendula, also called Pot Marigold, are a cheerful addition to any flower bed. Sow seeds in the garden as soon as the soil can be worked; in mild climates plant in early fall for bloom in late fall and winter. The 2" double and semi-double flowers in this mix bloom in shades of orange and yellow on plants that grow 18-20 inches tall. For extra early bloom, start seeds indoors 6 weeks before the last frost.
'Jewel Mix' Nasturtium (Tropaeolum majus) - Sow the seeds of these fast-growers after the soil has warmed and you'll be rewarded with a profusion of 2" double blossoms in shades of yellow, orange and deep red from July until frost. Seeming to thrive on neglect, nasturtiums are an easy care choice. This compact, 15" tall variety is a good choice for small yards and hanging baskets.
Four o'Clock Mix (Mirabilis jalapa) - This old-fashioned favorite bears marvelous, trumpet-shaped flowers that open in late afternoon or on cloudy days. The red, pink, yellow and white blossoms continue from summer to frost on 24" tall plants that thrive in full sun or part shade. In long-season areas, sow outside about a week after the last frost date. In shorter season parts of the country, start seeds indoors 6-8 weeks before the last frost.
'Large Flowered Mix' Sunflower (Helianthus annuus) - These easy to grow garden giants reach 6 to 10 feet tall from seeds planted directly in the garden in a sunny spot after the last frost date. The 6-inch, yellow, red and bronze blossoms are great for flower arrangements, but be sure to let some of the flowers set seeds for birds to enjoy.
One of the best things about annuals is that most are easy to grow. And planting seeds outside where they are to grow is simplest of all. It's a great way to start seeds of quick growing plants and those that don't take well to transplanting. It's also a good way to fill in with color around spring flowering bulbs and perennials that become dormant as spring turns into summer.
To get your garden bed ready for planting, clear away any plant debris and mulch from the previous growing season, mix in a few handfuls of a complete fertilizer and an inch or two of compost, then rake the bed smooth. Scatter small seeds lightly over the area or place larger seeds individually, then cover with soil to the depth recommended on the seed packet. Keep the seedbed moist, but not soggy, until seedlings emerge. When young plants are a couple of inches tall, thin to the recommended spacing.
Starting Seeds Early Indoors
For earlier bloom, many annuals are candidates for starting seeds easily indoors. Start with purchased pasteurized growing mix that has been lightly moistened. Fill small pots or shallow flats with the mix, then sow seeds at the recommended depth. Cover the pots or flats with plastic to keep humidity high, but remove it as soon as you see any seeds sprouting. Bottom heat from heat mats will speed germination of many seeds. Grow seedlings on under fluorescent lights or in a sunny window. Once outside temperatures begin to warm, harden off your seedlings before setting them outside by gradually getting them accustomed to outdoor temperatures and light intensities.
Taking Care of Annuals in the Garden
Annuals are a good choice for gardeners interested in low-maintenance gardening. Get them off to a good start and you'll spend more time enjoying their colorful blossoms than doing garden chores. Mix in an organic or slow-release fertilizer at planting time, then give your plants a boost with a soluble fertilizer once or twice during the growing season. Keep weeds at bay with an organic mulch.
Probably the most important chore to keep up with is deadheading, or removing the spent flowers before they can set seeds. This will keep your annual producing new flowers all season long. If you let the plants set seeds, they think their work is done. But if you want your plants to self-sow, let some flowers go to seed toward the end of the season. And, as mentioned, let some of your sunflowers set seeds to feed the birds.
The End of the Season
Frost will bring an end to your annual garden, but don't pull up your plants. Cut them off at their bases, leaving the root system in the soil to decompose and add organic matter to the soil. Then spend the winter thinking of new ways to use annuals for color in your garden next year.
Q:I would like to save the seeds from my sunflowers. How do I do this?
A: You'll need to let the seeds mature on the flower-heads before you harvest them. You'll know they're ready when the green bracts that surround the flower turn brown and the back side of the flower turns yellowish. This may take up to 3 or 4 weeks after the petals fall from the flower. However, the birds will be watching for the petals to fall as well, ready to harvest your seeds first unless you protect the ripening flower-heads. So when you see the petals start to fall, enclose the individual heads in paper bags until the seed is mature. Then cut the heads and hang them in a dry spot with good air circulation for a couple of weeks or until the seeds come away from the heads easily. Store the seeds at room temperature in an airtight container with some commercial desiccant to keep them from getting moldy. Then you can share your bounty with the birds over the winter months.
Article published on June 28, 2011.