The historic Seventh Avenue Parkway boasts 20 of Denver's loveliest flower beds: 19 annual gardens and one perennial garden.

Karen Zeldin, a city parks horticulture worker, is planning her fourth season of designing and tending the parkway's plantings.

"We have so many beds that I can't go too crazy with intricate designs," Zeldin said.

She germinates ideas for simple plantings that are anything but plain, thanks in large part to imaginative color combinations. Last season, for example, Zeldin filled five flower beds at Milwaukee Street with creamy white canna lilies, basil so dark it looked almost black, and miniature pepper plants with tiny, lemon-yellow fruits. The result was dramatic and wholly unexpected.

This year,

Be sure to look beyond blooms for color, like these dramatic leaves of impatiens, sweet potato vines and begonias.

one of Zeldin's brightest plans calls for planting a mix of "Braveheart" begonias — bi-colored light pink and rosy pink — a dark purple heliotrope with bright green foliage and celosia "Fresh Look Orange."

Color, of course, is only one consideration when purchasing plants, but it is a primary concern.

Zeldin emphasized remembering that plants' cultivar names aren't always true blue. "It might be called 'scarlet,' but it might end up being more pink," she said. "You can't go by the names."

Zeldin also notes that plant colors change.

"They're different at different times of the day," she said. "And the color depends on heat and light."

Mike Eagleton holds landscape-design and graphic-design degrees from Colorado State University. The owner of Mike Eagleton Landscape Architecture and Design, he produces head- turning gardens and splashy containers, including the huge pots along the 16th Street Mall. Also a botanic illustrator, Eagleton has an eye for color.

He's persnickety about plants, but when it comes to planning gardens, Eagleton encourages a relaxed spirit of horticultural adventure.

"You don't want to overthink it, or people get all bundled," Eagleton said. "There are 8 million different

Pink petunias, orange marigolds, purple globe amaranth and two types of rudbeckia show variety within a limited palette. (Mike Eagleton)

color schemes. It's all personal preference. Just pick colors you love."

But to create more cohesion, Eagleton advises limiting the color palette.

"People go to the nursery and get excited about individual flowers and colors. They say, 'I love that. I love this.' But if they're dabbling here and there with colors, it has zero impact in the yard," he said.

"The true test is when you put all your plants in the cart. If you're not seeing continuity or a theme, you've got trouble," Eagleton said. "If there's not enough commonality between colors in the cart, when you put the plants in your garden, it's just polka dots."

Landscape impact often requires quantity: "People never purchase enough," Eagleton said.

He also underscored

Different textures in the same hues of blues (hyacinth, grape hyacinth and pansies) create drama without busyness. (Mike Eagleton)

the value of accent colors.

"You want something to hold it all down, to mitigate bold colors or provide a segue," said Eagleton. "When you do pink and orange, you get great contrast and clash, but yellow mixed in softens everything."

Eagleton often works with yellow, white, silver, lime green, blue and pale peach as accents.

"If you're going to use an accent, use only a little bit of it," he said, "but it can't be all in one place because the eye will go instantly to it."

One of Eagleton's favorite color combinations mixes black, silver, salmon and lime green. He's also a fan of red, orange and lime green.

"I think people are ready to get into sophisticated color schemes and get some excitement in their life," he said.

Denver writer Colleen Smith blogs about gardening and other interests at