Gardeners have always enjoyed phlox, a native of North America whose name derives from the Greek word literally meaning ‘flame-coloured’. The plants have also come to mean ‘sweet dreams’ or ‘harmony’.The colours are wonderful and are more than just flame-coloured as they include shades of red, purple, scarlet, yellow and white, some with a flirty eye. The evening scent is captivating, and they are easy to grow. 

Phlox is an old fashioned flower deserving more recognition than it gets. The large, jewel-like flowers grow in clusters at the top of the stems and are very showy on these compact plants. ‘Compact’ is an understatement, as they usually grow to only 6-18 inches tall. Despite their small size they make good cut flowers, and are great when planted in containers or window boxes.

Propagation of Phlox Seeds

The most common phlox is the half-hardy annual although there are perennial varieties too. Perennial phlox can be divided every two to three years but the annuals are best grown from seed. The seeds can be sown directly into your flower garden when the last frosts have passed, but are best sown indoors in early Spring for transplanting later in early Summer.

Cover the seeds lightly with ⅛ inch of fine garden soil or potting compost and water once thoroughly. Given a sunny position, young seedlings will transplant well into their permanent home and will look great filling the gaps in a flowerbed or planted at the edge of a border.

How to Grow Phlox Plants

Young phlox plants should be placed 8 to 10 inches apart in full sun. They prefer rich, loose soil that drains well. Add a general purpose fertilizer when planting them, then once a month after that.

Once your Phlox plants are established, they should grow well with few problems. Keep the soil moist to slightly dry, watering them during dry periods, once or twice each week. Keep them well weeded, or apply a 2-3 inch layer of mulch for a tidy appearance. Pinch back tall stems to promote a bushier appearance.

Tip: Remove spent blooms to promote additional blooms and extend the blooming period all summer long, and right up to the first killing frost. This will also keep the appearance neat and fresh.

Phlox are half-hardy annuals so they will often survive the first few light frosts. They will not, however, survive a hard frost or a freeze.