Garden Detective: Lucky bets for summer planting

Debra Cox of Peconic plants diascia. (April 30,

Debra Cox of Peconic plants diascia. (April 30, 2013) (Credit: Randee Daddona)

All over the world, in cultures that sometimes seem to share little else in common, the number seven is perceived as lucky. It's also a significant number in the natural world, which makes it even more important to gardeners like us: There are seven colors in a rainbow, seven days in a week, seven wonders of the world and seven musical notes in an octave. The Bible is filled with references to seven signs, seven days, seven angels, seven seals. Southern Italians celebrate Christmas Eve with the feast of the seven fishes, Japanese folklore nods to the seven gods of luck and Buddhists look to the seven factors of enlightenment.

Seven also is an ideal goal in garden design, which favors odd numbers of plantings for visual asymmetry. What's more, in our part of the country, we're gardening in lucky Zone 7.

So I'm pretty confident this will be a great year: It's my seventh year as Newsday's garden columnist. It's been my privilege to write for you, meet with you, answer your questions and weigh your contest tomatoes all these years. And something tells me this is only the beginning of our journey: In Chinese numerology, seven symbolizes togetherness.

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PHOTOS: 7 Impatiens alternatives | 7 annuals for sunny spots | 7 annuals that will grow tall quickly

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As gardeners, we have many decisions to make during spring: Should we expand the garden and shrink the lawn? Start vegetables from seeds or buy starter plants? Splurge on the water feature displayed at the nursery's entrance or put that cash toward a weekend getaway? Without fail, the one decision I struggle with each year is how to balance the ratio of new perennials, which typically bloom for just a few weeks each season and take several years to attain their full potential, and quick-fix annuals, which will grow quickly, provide near-instant gratification and bloom nonstop from spring through frost.

Annuals theoretically are those plants that complete their life cycles -- from seed to death -- in one year. But from a practical standpoint, we've come to include tender perennials -- those that thrive here in summer but die because they cannot survive New York winters -- in the "annual" category as well. These plants are cheaper, typically are sold in multi-plant cellpacks and provide a lot more (albeit, temporary) bang for the buck than perennials.

Impatiens have been the go-to annual for shady beds and planters for as long as I can remember. They asked for little, generously allowing us to forgo deadheading, pinching and staking, and nevertheless rewarded us with brilliant color from Mother's Day straight through frost. All they required in exchange was a little shade and a little water. But as is too often the case, all good things must come to an end: We're now being forced to part ways with our dear, old friend, at least for the foreseeable future.

Last year, a disease called downy mildew declared open season on impatiens, and the results weren't pretty: Leaves turned yellow and fell off, plants were severely stunted and gardeners who looked closely noticed the presence of a white substance under leaves. For some, there was the bizarre "disappearance" of plants altogether -- seemingly there one day and "where did it go?" the next.

The bad news is that we should avoid planting impatiens until a cure is found, and that's not likely to happen for several years. The good news is that, although the pathogen -- Plasmopara obducens -- very well might have survived winter in the soil, it is host-specific, which means it only poses a threat to Impatiens walleriana. Other plants will not be infected if planted in the same soil this year. Even New Guinea impatiens are safe, as they belong to a different species not targeted by the disease. However, because the New Guinea variety requires a bit more sun than ordinary impatiens, they aren't suitable replacements for the shadier spots where their stricken cousins have thrived in the past.

Linda Frohlinger has been planting impatiens in her Massapequa garden for 30 years, tucking pockets of red and white, or violet or pink plants into corners to brighten up beds around her hostas and ferns.

"I love to garden and be in the dirt and feel the worms, and I love my impatiens" she said mournfully. "I'm about to have my first grandchild, and one of the things I am looking forward to is teaching her to plant flowers. One simple thing that can give you a lot of pleasure is putting impatiens in the ground and watching them grow quickly."

This year, Frohlinger knows she'll have to alter her decades-long routine. "I have shady areas where I always have a pot or two of coleus up on a rock," she said. "This year I'm going to get more coleus for the ground instead of impatiens."

So what can you plant this year instead of impatiens? I've spent the long off-season pondering that dilemma. In addition to coleus, I sought flowering annuals with a long bloom cycle that are low-maintenance, can tolerate at least some shade and have the same suitable-for-bed-or-container habit as our beloved standby. It wasn't easy, but I did find seven solid alternatives I think you'll like.

7 ALTERNATIVES TO IMPATIENS

Vinca (Catharanthus roseus): Not to be confused with vinca vine, a perennial ground cover, this annual resembles impatiens more closely than any other substitute and is available with lavender, white, red or pink blossoms. It can handle some shade, but flower size increases dramatically with sunlight exposure. Perfect for hot, dry sites, this plant is drought-tolerant, "self-cleaning" (no deadheading necessary) and can be brought indoors for winter windowsill color. Grows 6-16 inches tall and wide.

Begonia, tuberous (x tuberhybrida), wax (x semperflorens-cultorum) or hiemalis (x hiemalis): Requires ample water and fertilizer; grows 6-18 inches tall, 6-12 inches wide.

Clown flower (Torenia): Doesn't bloom quite as prolifically as impatiens but is very attractive and thrives in light shade while tolerating heat. Flowers are deer-resistant; grows 8-12 inches tall, 6-9 inches wide. Try the 'Summer Wave Blue' variety.

Flowering tobacco: (Nicotiana 'Starmaker'): Requires just six hours of sunlight per day. Deadhead to prevent self-sowing; grows 10-12 inches tall and wide.

Lobelia: Available in cascading and mounding varieties. If plants stop blooming during heat waves, shear plant to encourage another burst of flowers; grows 6 inches tall, 6-9 inches wide.

Petunia: Performs best with 6-8 hours of sun daily. Pinch or cut back by half in midsummer to rejuvenate plants; vines of "Wave" varieties can trail up to 4 feet long.

Amethyst flower (Browallia): Prefers rich soil, so add compost at planting time, then mulch to keep roots cool. Available with purple, blue or white flowers. Grows 12-24 inches tall, 6-12 inches wide.

OTHER ANNUALS

Plenty of annuals bask in the glory of full sun, with common geraniums, marigolds and New Guinea impatiens among the most popular in the region. But there are so many other, less common choices available.

Debra Cox of Peconic is planting Diascia, commonly called twinspur, in her garden this year. The lushly flowered annuals are ideal for spilling abundantly over container edges and retaining walls. They also fill in nicely between bedding plants, requiring only a sunny site, fertilizer and moist, well-draining soil. And shearing after the first flush of blooms will encourage another.

Although Cox has planted Diascia in pots before, this is the first time she's planting it directly in the garden. She always gives her children, ages 11 and 4, a say in what she plants: "We picked it for the color because it's bold," she said, adding that the variety she purchased is called "red" but is really pink. "The kids pick it out, they just never want to do the planting," she mused, recalling a scene that's all too common in backyards across America.

If you, too, are looking to break with tradition and branch out into new territory, try planting one of my favorite sun lovers this year. Better yet, try to get the kids (or the grandkids, or the neighbor's kids!) to plant them.

Lantana: Suitable for beds, borders, containers and even as ground cover, lantana produces an abundance of solid or multi-toned, deer-resistant, fragrant flowers all season long.

Angelonia: Varieties include those with white, pink or purple flowers. Plant in the garden or in containers, and snip flower stalks for indoor vases.

Moss rose: (Portulaca): Perfect for hot, dry spots, this succulent tolerates drought and poor soil like a champ. Available in many primary and pastel shades. Deer-resistant, very low-maintenance; suitable for containers, beds, borders and as ground cover. May reseed.

Zinnia: Varieties include single daisylike types as well as semidouble- and double-flowered. Available in myriad colors, including various shades of orange, pink, yellow, purple and white. Suitable for containers and/or beds, depending on variety.

Ageratum: Old-fashioned favorite available with lavender, white, rose or nearly-blue (a rarity) flowers. Suitable for containers, beds and borders, with height among varieties ranging from 6 inches to 3 feet tall.

Calibrachoa: Resembling mini-petunias, these adorable cascading annuals are covered with hundreds of flowers all season long. Sprawling habit makes the heat-tolerant plants best suited to containers or the front of a border, where they will gracefully spill over onto a walkway. No deadheading necessary. Look for "superbells" varieties, available in Red, Plum, Yellow, Lavender, Yellow Chiffon or my favorite, Blackberry Punch. Fertilize regularly for best color.

Snapdragon: With little flowers that appear to roar like lions -- or dragons -- when their sides are pinched, these aptly named old-fashioned upright beauties are available in many different colors and even a few bicolor varieties, among them mauve and white, pink and white, purple and white, orange and creamy yellow.