Gardening is about plants.

Other things are involved, including soil, sun, animals, birds, insects, designs and emotions. But plants are at the center, around which everything else revolves.

For that reason, the most popular programs at New England Grows, a huge trade show held every year in Boston for landscapers, arborists and nursery workers, are those where the talks stays firmly on plants.

Kelly Norris, horticulture manager of the Greater Des Moines Botanical Garden in Iowa, has some problems with the directions that flower producers are taking.

“Take a category like mums, which we’ve all but ruined, creating a sub-shrub that lasts a single growing season,” he said during his presentation last month. “It’s sold in a pot and has a lifespan of three and a half weeks.”

Plants like that are not going excite anybody, he said, because the mantra today is gardening with a purpose. There are more than 250,000 flowering plants in the world, yet only 15,000 in the commercial market. How do people choose which ones to sell?

“The best question to ask of a plant is ‘Does it feed me, make me happy or spread so I can share with a neighbor?’ ” Norris said.

Plantago “Purple Perversion” excites him. It is related to plantain, which is a common lawn weed (not the fruit, which is another plant entirely).

Its purple-red color deepens in the fall: It has ruffled leaves, is striking and will last forever. “It’s a damn weed that comes true from seed,” he said. Maybe it works for him, but I doubt I’ll be putting it in my garden this season. It just doesn’t appeal to me.

Shasta daisies always appeal to me, but Norris wonders about newer versions of shastas, which he calls grandmother plants, even though they are a hybrid that took Luther Burbank 13 years to create a century ago. A new variety, “Daisy Duke,” is shorter and whiter, but what’s the purpose? It might fill a spot in your garden that needs something short and white.

He said people have gone cone crazy, developing and marketing all sorts of new echinaceas. Hybridizers have created great new colors with cultivars such as “Tomato Soup,” which crosses the long-lived Echinacea purpurea from the prairies with short-lived Echinacea paradoxa from the Ozarks. They survive a few years at most.

“They’re flower powerhouses,” he said, “but they burnt through all their reserves and are effectively an annual.”

In our gardens, my wife, Nancy, and I still have the original rosy purple echinacea that everyone started with. I like them, and I’m not going to buy “Tomato Soup” this year, just as I didn’t buy “Macaroni and Cheese” last year. The original echinacea has lasted for a decade in our garden, stands up straight, has great blossoms and few predators, and the leftover cones look great all winter after the petals fall off. That’s enough for one plant to do for me.

In another talk at the New England Grows trade show, Jared Barnes, a professor at Stephen F. Austin State University in Texas, said that people personify their plants.

“They comment on how they weep, look sexy, have a nice personality in the landscape and aren’t thugs,” he said.

He prefers extroverts – plants that make you sit up and take notice. As a result, he includes a lot of chartreuse plants on his must-have list. When eyes adjust to night, they lose reds and blues early, with chartreuse being the last one perceived, he explained. And it’s fine if the color is in the foliage.

“Flowers sell, but foliage lasts,” Barnes said.

Among the chartreuse plants he recommended were Hydrangea quercifolia “Little Honey,” redbud “Hearts of Gold,” witch hazel “Wisley Supreme,” spirea “Ogon,” Aralia cordata “Sun King,” tansy “Isla Gold,” bleeding heart “Gold Heart” and yucca “Color Guard.” The last, he said, acts like a highlighter in the garden. I will look at these plants, think about them and possibly buy some, but I’m getting to be plant fussy. I’m not buying everything someone recommends.

His garden is not all chartreuse, of course. Even if it is the brightest color, things would be boring in all one color.

“Ruby Falls” is a cascading redbud with purple foliage. Clematis “Rooguchi” will look like it’s going to die for a couple of years and then produce bell-shaped blue flowers that last from May to September. The “Bihou” Japanese maple starts with red foliage, fades to orange and has orange twigs for winter.

It isn’t always color that makes extroverts. Shape matters, too. The “Contorta” flowering quince, for example, has twisted stems, so it will provide great winter interest, and in spring, when it produces its pink blossoms, the stamens are also twisted.

In her talk at the show, Lois Berg Stack of the University of Maine, discussed research that she, Frank Drummond and Alison Dibble are doing in the Orono area to find out what native plants help bees most.

She told the professionals that such plants might lure younger customers. “Young people are not gardening, but they are concerned about the environment and concerned about bees,” she said. “If we can get them to plant a little place for pollinators, there is huge potential.”

Both herbaceous perennials and woody plants provide food for the bees, and she advises putting a lot of the same plant close together because bees like a feast. Plant them in the sun, because bees feed in the sun, and plant different varieties so something will be in bloom at all times.

Among the best pollinators are asclepias, clethra, agastache, herbs such as borage and those in the mint family, willows that bloom early, spireas, asters and wild strawberries. And it’s interesting to me that all the good pollinators are also “grandmother plants” and they are reliable, nice plants (OK, I’m personifying here) that have withstood the test of time.

So there are many ways you can pick your plants: by their ability to lift your mood, personality, or environmental good citizenship.

And the best part is, many plants fit all three categories.

Tom Atwell is a freelance writer gardening in Cape Elizabeth and can be contacted at 767-2297 or at tomatwell@me.com.