Planting Annuals: When and How To Plant Annual Flowers

Learn the ins and outs of planting annuals, including when to plant annuals and techniques you can use to boost success.
Knee High Mix Sweet Pea

Knee High Mix Sweet Pea

Grow an old-fashioned favorite by planting a crop of sweet peas. This pretty bloomer was a favorite in the Victorian era, when nosegays of sweet peas were cherished for their fragrance. ‘Knee High Mix’ sweet pea features a blend of perfumed types that open flowers in shades of pink, lavender, rose, purple, burgundy and white. Sweet peas grow best in cool seasons. Plants peter out when summer heat and humidity arrive. ‘Knee High Mix’ grows shorter vines, reaching 2 to 3 feet tall. Annual.

Photo by: Ball Horticultural Company

Ball Horticultural Company

Planting annuals in beds or pots marks the beginning of a season-long show of eye-catching flowers and leaves. Annuals race through the growing season, unfurling flowers and colorful foliage until frost arrives on the scene. Knowing when to plant annuals helps get the seasonal show off to a solid start. Understanding how to plant annual flowers is the other key to success. 

Some annuals thrive in cooler seasons of the year, while others need a little summer sizzle to strut their stuff. Typically garden centers sell the appropriate annuals for the season at hand—or soon to come. If in doubt, ask. This is especially important in early spring, when summer annuals have started their growing season in the cozy confines of a warm greenhouse. Once they enter the world of cool spring nights, they often stop growing. For these heat-loving annuals, planting too early can pronounce a death sentence as chilly air and cool soil causes plants to stall or even rot. 

The ideal time to plant is on a cloudy day. This protects newly planted annuals from having sun stress seedlings as they’re settling into their new digs. Another option is to tackle planting chores in the evening, which gives plants the overnight window to recover. If you must plant on a sunny day, consider erecting some sort of shade device to protect seedlings. A piece of cardboard or bedding plant flat propped up to cast shade works fine. 

Before planting annuals in a bed, it’s a good idea to arrange plants—in their pots—in the pattern you’ll follow when planting. If you’re planting a container, arrange pots on the work surface beside the pot. With in-ground beds, finesse the spacing based on mature plant size. Give plants enough room to spread and soar. 

It’s not hard to master how to plant annuals. Water any annuals that are dry before removing them from cell packs or pots. Root balls should be moist at planting time. Never pull annuals from their containers—that’s a good way to break stems. Instead, remove plants from their containers by gently squeezing the pot and then flipping it over, cradling the annual stem with your hand. It should slip right out. 

Use your hand or a trowel to dig a shallow hole large enough to cradle an annual’s root ball. If you’re planting many annuals, try the method professional landscapers use: the stab-and-plant technique. Hold a trowel with the blade facing down and the concave side facing you. Stick the trowel into soil, and pull the handle forward, creating a hole behind the blade. Slip the annual from its container and drop it into the hole, firming soil around the plant. This method works best with loose soil. 

Always water annuals after planting. Use a watering can or hose-end sprayer or watering wand that delivers a gentle shower of water. Soak soil thoroughly. Add a mulch layer to slow water evaporation from soil and help reduce weeds.

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