Whether you have a cool, shady garden (relatively cool — this is Texas, after all) or a sunny one that shines when it’s scorching, look for colorful, inexpensive annuals to transform your landscape from season to season.

Annual plants have a life cycle that lasts one year, starting from seed to flowering, producing more seeds and dying within the same growing season. Some annuals have longer growing seasons, lasting through spring and summer, for example, but typically don’t live through the winter, or vice versa for cool-weather annuals.

Annuals can be purchased from nurseries as transplants or can be sown directly from seed, depending on your preference. Transplants are often sold in small pots, packs of six or hanging baskets. Small plants are economical and don’t require the conditions and attention sometimes necessary for seed starting. As well, some plants are difficult to transplant from seed. Transplants are excellent choices for dropping right into well-defined beds with designated areas for specific plants.

For swaths of color in a cutting garden area or a free-flowing English-style garden, seeds can be scattered and left to grow and reseed on their own. The cosmos in my cutting garden begins in late spring and continues to grow and bloom in waves through fall. As the taller stems begin to fade and die, new shoots are already sprouting on the ground beneath them.

RELATED: How to get rid of mosquitoes in the yard

Plan carefully, though. Vigorous reseeders have a mind of their own and will drift throughout your garden, with no consideration of your carefully crafted design plan! Be careful if you don’t want to spend time pulling up wayward blooms later.

I like to think of annuals as icing on the garden cake. Evergreen plants and shrubs provide the base of the garden, perennials help create layers, and annuals finish it off with a flair.

Annuals aren’t just for front borders of landscape beds. Many tall, dramatic annuals offer striking interest for the backs of beds. I mix in plants like cleome, Brazilian verbena, cosmos and sunflowers to add a pop of blooming color and height to my summer beds.

With regular deadheading, many annuals will continue to bloom throughout their season. "Cut and come again" zinnias do just that, and they always enjoy a prominent place in my garden. They brighten up my beds, and I often cut stems to bring into the house in a vase as well.

Annual herbs also make excellent plants to incorporate into your ornamental landscape. I regularly tuck a few purple basil plants into a sunny bed for color. Not only do they look good, but a few snipped leaves also make a delicious addition when I cook Italian or Asian meals. Because I share my garden with deer — who don’t like herbs — they can provide a deterrent to keep deer away from other plants.

Just as with evergreen or perennial plants, annuals provide a wide range of textures and forms. Use them to climb up and thrill, fill and spill throughout your garden, just as you would in containers.

Grandpa Ott morning glory vine regularly climbs the trellis beside my mailbox each summer, adding vertical interest. Chartreuse and eggplant-colored potato vines make electric ground covers and spillers for walls and pots. And snapdragons thicken and fill spaces between perennials.

RELATED: It's not too late to grow food this summer

Perfect for pots as well, annuals make it easy to switch out container designs from season to season. When the spring pansies start to wilt in early summer heat, it’s time to pop in some zinnias or geraniums.

As with any plants, use care when combining plants in your landscape beds. Hot, dry beds with agaves or grasses aren’t the best location for thirsty little zinnias. If water needs differ, you might inadvertently over- or under-water something in the bed. Water-holding annual succulents like moss rose or purslane will fare much better in a dry bed that stands up to the scorching sun.

And, remember, less xeric annuals have shallow roots; they may need to be planted where they can be watered more often. As always, a good layer of mulch is important heat and evaporation protection for your plants.