Americans are a mobile group — one in five of us moves every year. It’s easy to see why container gardens are so popular. Aside from being smaller than a typical garden, requiring less time and money to plant and maintain, they are portable. Potted plantings are thought by many to be essential accessories for outdoor seating and dining areas.

Four simple ingredients

A container garden is easy to create, limited only by your imagination and needs only four elements: appropriate containers, soil, water and, of course, plants.

First, decide on the pot or object to hold your garden. You may choose a decorative pot, a trough, a pail or even an old boot. Use any container that’s water-resistant, has at least one drainage hole through its base (the more the better), and can hold potting soil. Bear in mind that small containers dry out faster and require more attention than larger ones. Generally, a 12-inch pot is a good size to work with and is the minimum dimension for plants like patio tomatoes.

Use a soilless potting mix specially formulated for container plantings. This medium is lightweight, won’t pack down, is disease-free and provides good drainage. Add water-retaining polymer crystals to curb rapid evaporation, and sprinkle in a small amount of time-release fertilizer that will last through the growing season. When you water, use a liquid fertilizer diluted to half strength every other week. Check the moisture of the soil daily to gauge how quickly it dries out.

The most important rule to follow in plant selection is to plant what you love — whether it’s bright colors, fragrant blooms, kitchen herbs, dramatic shapes and textures, or arching, cascading waterfalls of foliage.

For something different, try a themed vegetable garden. Consider a salsa garden with bush tomatoes, jalapeño peppers and cilantro; a salad-bowl garden with leaf lettuce, sweet peppers and cucumbers; or a pizza garden with Roma tomatoes, basil and oregano. Or, attract butterflies with a garden filled with purple coneflowers, parsley, bronze fennel, black-eyed Susan and verbena. As long as the light and watering requirements are similar, any combination of materials will work.

Use your imagination

Include enough plants to make your container appear full. In fact, most plants bloom better in tight quarters. Some designers feel an arrangement should reach one-and-a-half times the height of the container. Others favor strong angular dimensions with foliage trailing off the edge of the pot.

Your project will have more visual interest with a mix of at least three leaf shapes, high color contrast and a mix of plant elevations including tall, mounding and trailing. If you use evergreens, you’ll have year-round interest. You can also style different arrangements for each season.

After creating your container garden, think outside the box. Potted arrangements of trees and shrubs can serve as landscaping on a patio, deck, terrace or front porch. You can also arrange containers among nonblooming shrubbery for a splash of color or textural interest.

Imaginative style, convenience and portability define the horticultural trend toward container gardens. Take advantage of it and enhance your outdoor space.