Tulips and dandelions are some of the most popular choices among gardeners for flowers that make an early spring appearance. But colorful blooms of creeping phlox, spilling over retaining walls or boundaries, are also a common sight.

There's no shortage of choices for anyone looking to add phlox to their garden. The Clemson University Cooperative Extension says there are hundreds of different varieties of the perennial wildflower, ranging from ground covers to tall flower stalks.

It helps to research the different species and cultivars of phlox to determine which ones will work best at your home. Woodland phlox is a good choice for a ground cover, since it forms a spreading mat and grows well in shade. Tall phlox can grow to a height of up to five feet; the National Gardening Association says it works well as a background plant, with early summer blooms.

Phlox varieties are prized for their blooms of multiple star-shaped flowers, which are sometimes so vigorous that they completely hide the plant's foliage. Sandra Mason, writing for the University of Illinois Extension, says they typically come in shades of white, red, pink, or purple. Some species have centers with a contrasting color. The flowers are a good way to attract butterflies and hummingbirds.

The sun, soil, and other needs of phlox will vary depending on the species. The Clemson University Cooperative Extension says some low-growing varieties prefer ample sunlight, while others prefer shade. Tall varieties tend to do best in full sun or partial shade.

While some varieties will grow well in sandy soil, phlox usually prefers rich, well-drained soil. The Old Farmer's Almanac recommends loosening the top 12 to 15 inches of the soil and working in compost before planting phlox.

Cuttings or transplants do better than seeds, and there should be one or two feet between plants. If you are moving phlox from a pot, dig a hole in the ground that's about twice as wide as the diameter of the pot before the transfer.

Look for large, lush plants when picking out phlox cuttings. Longfield Gardens, a company in Lakewood, N.J., says phlox will establish itself well if it has a strong root system.

The best time to plant phlox is in the spring, after the danger of frost has passed but when weather conditions are still cool and moist. The Old Farmer's Almanac says it also helps to put down a layer of mulch around the plants to maintain moisture and deter weeds.

Phlox are relatively maintenance-free plants. If they receive less than one inch of water a week through regular rainfall, you'll need to make up the extra moisture. Mason says the plant should be watered at the base to minimize the possibility of disease.

An all-purpose fertilizer applied in the spring can help keep the plant supplied with nutrients as it grows. Longfield Gardens says you can also pinch back the tip of the shoot when it reaches a height of six to eight inches to help promote a bushier plant.

Blooms will gradually fade, so it is important to remove any dead or faded blossoms to prolong the flowering period. Mason says you can also strip off any dead leaves to make the plant look tidier.

Several problems can potentially affect phlox. The Old Farmer's Almanac says these include rust, leaf spots, caterpillars, leaf miners, and stem nematodes.

Phlox is most likely to be damaged by powdery mildew, an ugly grayish fungal coating that attacks the foliage and weakens the plant. The Clemson University Cooperative Extension says this condition is most likely to occur in warm, moist conditions.

In addition to choosing varieties that are resistant to powdery mildew, gardeners can reduce the possibility of disease by ensuring that phlox plants are spaced out adequately to allow for proper air circulation. Mason recommends thinning out the stems of tall phlox so there are no more than five or six strong ones in each clump. Remove and destroy any leaves affected by powdery mildew.

Phlox will self-sow by dropping seeds from spent flowers, which can be helpful if you want to create a more natural and wild appearance. However, these seedlings can also be hard to control since they'll gradually take on colors separate from the parent plant. Longfield Gardens says these plants also tend to be weaker than the parent plant.

Tall phlox require some additional care at the end of the season. The National Gardening Association says the stems should be cut down to one or two inches above the soil after the first hard frost occurs in the autumn. The plants should be divided every two or three years to prevent crowding and disease.