Mother’s Day weekend traditionally marks the kickoff of the get-serious gardening season in the Lower Hudson Valley because by now we can generally say that any danger of late frosts is pretty much gone, making it safe to buy and plant tender annuals like begonias, sunflowers, cosmos and coleus. Yay, right? It’s been a long slow wait to get going this year.
Annuals — these are the plants that don’t come back from year to year, unlike perennials — are all about having fun in the garden. They’re whimsical and exuberant and wildly colorful. And you can change them up completely from year to year. Create a hot-color tropical garden with cannas, dragonwing begonias, dahlias and fuchsia one year, then turn it upside down the following spring with cool cleome, pansies, ageratum, scaevola and New Guinea impatiens.
(dahlia coming into flower at Stew Leonard’s earlier this week, by Ricky Flores)
Remember that what we consider an annual is most likely a perennial in another climate.
“Ninety-five percent of the stuff we use are really not annuals,” says Mike Ruggiero of Lake Peekskill, who gave a talk on annuals at the Chappaqua Library last month as part of the Westchester Master Gardeners’ Home Gardening Lecture Series. “My definition is that an annual is anything you use that dies. Period. It’s an annual.”
We’ll be seeing more and more annuals every year, he predicts. “I love the fact that you can get mandevilla at the A&P.” He’s also crazy about all the office buildings and corporate parks in Westchester that are now planting huge beds of annuals, using wax begonias, cannas, petunias, zinnias and French marigolds to create a summer-long carpet of color.
Don’t limit your definition of annuals to plants with pretty flowers, says Ruggiero, the retired longtime curator at the New York Botanical Garden. Lots of vegetables and herbs are annuals, and many of them combine wonderfully with flowers, in a container or out in your garden. Think of all the bright color options for Swiss chard these days, or the basils and mints that now come in a rainbow of colors — and flavors. In fall, use ornamental kales and cabbages in your window boxes and garden beds.
And many great annuals are known more for their colorful and intriguing foliage — coleus, cannas, elephant ears, dicondra and sweet potato vine —than their rather insignificant and boring flowers.
Don’t rule out ornamental grasses either. Ruggiero likes Pennisetum ‘Fireworks.’ “It makes a great centerpiece and flowers all summer.”
Annuals are a must if you have perennial beds, he says. They’re just the thing to fill in holes in your garden created by perennial blooms that have come and gone. Most perennials bloom for just a couple or three or perhaps four weeks and then they’re just ho-hum in your garden. Annuals will give you season-long color. “They weave everything together,” Ruggiero says. “They finish your garden off.”
And do keep a weather eye out for possible but rare late frosts after this weekend. If one is forecast, just cover your annuals with sheets or pillowcases to protect them.
Annuals, especially ones in containers, are heavy feeders. To keep them thriving all summer, you’ll need to fertilize them with a water-soluble solution every couple of weeks.
Local plantsman Mike Ruggiero says the commercial brands you’ll find at any garden center — Peter’s, Coast of Maine, Rapid Grow, Flower-tone by Espoma — are just fine. He likes to use them every two weeks, at half-strength.
He also creates his own potting mix for containers by adding one-third compost to a commercial potting mix. This will enable the soil to better hold water and fertilizer.
Time-release feeding tablets are OK, too, he says, but they only work when the soil is warm (70 degrees), so there’s no point in adding them until the end of June.