Pretty flowerpots are a garden’s centerpieces, and they don’t need a lot of pampering to make you and your garden look good. Fill some pots with colorful plants now, and enjoy them for months.

Joan Mazat plants hundreds of flowerpot combinations every year as part of her job with the Ball Horticultural Co. near Chicago. Mazat is in charge of poinsettias, geraniums and cut flowers, but she has been working with the company’s team of flowerpot experts for years, “in charge of everything weird, wild and wonderful,” she says. Snazzy combinations in flowerpots are her specialty.

Every year, Mazat and the Ball flowerpot experts put together more than 200 combinations of annual flowers, and 120 or more pots of perennials or of mixed perennials and annuals. The plantings are part of the company’s plant trials; it is also a way to supply garden shop owners and gardeners with a little inspiration.

Mixing annuals, perennials and shrubs in flowerpots is a great idea, Mazat says. “Most people will not put annuals, perennials, shrubs and foliage plants together,” she says, but the effect can be stunning.

Mazat’s one, unbreakable rule for flowerpot combinations is a simple one: Do not plant sun-loving and shade-loving plants in the same pot and expect them both to thrive. “If you do that, you will be very unhappy with the results,” she says.

Shrubs are underappreciated choices for pots, says Stacey Hirvela, who works with Proven Winners ColorChoice Shrubs. Proven Winners plants look great growing by themselves in a flowerpot, but they’re even more fun with annual and perennial flowers and ornamental grasses, Hirvela says.

“I’m the kind of person who says, ‘The more the merrier,’ ” Hirvela says. “They pair well with trailing plants, with something rambling around and through, and sometimes with something else as a centerpiece.”

These days, garden shops make it easy to come up with good-looking combinations for flowerpots. Many have potting stations among the rows of plants, as well as tip sheets for shoppers. Customers can plant their purchases in pots right in the shop to see how they look. Some shops hold workshops and demonstrations for gardeners or offer ready- planted combinations.

Choosing plants that look great together is really as easy as walking around a garden shop and trying out combinations in a shopping cart, Mazat says. Plant tags describe the conditions plants like, so if you have a sunny spot, start by browsing the sun-loving plants, and pick out colors and textures that appeal to you. Mazat recommends starting with something big and striking.

“I start with my foundation plant — whatever I want to design around,” she says. “Then I take that plant and put it next to other flowers and see if it gives you a pop.”

Mazat loves pink and purple together. She recently designed a combination around a glimmering Persian shield plant (Strobilanthes) with purple leaves brushed with silver, adding a celosia, with its pink bottle-brush blooms, and a pretty, dark blue petunia with a white picotee edge. In another pot, she started with a flourish of Purple Majesty millet and paired it with soft lilac petunias and fuzzy-leaf plectranthus (sometimes called Mexican oregano).

The biggest or tallest plant doesn’t always go in the middle, Mazat says; it depends on where the pot will be placed. Formal pots might have a tall plant in the center with mounding plants around it, but, by varying where you put the tallest plant, you can have a pot that’s a lot more interesting.

Mazat and Hirvela both recommend using large pots (at least 18 inches across, on up to 24 inches) and enough plants so the pots look full right from the start. Hirvela says she usually chooses neutral pots to show off her plants, “but the pot can come first,” she says. “I don’t think anyone should deny themselves if they see a pot they love and their heart goes pitter-pat.”

Whatever container you choose, it should have drainage holes. After that, suit yourself. Mazat likes the fun of old washtubs and the trim sophistication of wire baskets lined with moss, but she has used inexpensive plastic pots, too. “I did a design for a friend in plastic pots, and I told him ‘You won’t see the containers in two weeks.’ ” Cascading, ruffled petunias and silvery dichondra spilled over the sides in no time and the pots disappeared. The flowers bloomed until the first frost.