Phlox Plant

A summer garden must-have, the Phlox plant boasts a series of heady billowing blooms and a slender structure. It’s also low maintenance! One of its most popular traits is its long flowering season, with the first blooms opening in July and often lasting well into the month of September.

Garden phlox is a versatile garden plant that comes in a variety of different hues, meaning there is something to suit all. This perennial even comes in rare shades of blue. The botanical name for this species of plant is Phlox paniculata. It’s also known as Garden phlox, summer phlox, tall phlox, and border phlox.

History and origin

Phlox plants are native to eastern and central America. It wasn’t until the early 18th century that it arrived in Europe, with many of the early cultivars originating in England and Germany.

The German plant breeder Karl Foerster established several cultivars that are still popular today back in the 1930s. He is famous for saying: ‘a garden without phlox is not only a sheer mistake but a sin against summer’.

Height and characteristics

This plant can grow between one and five feet tall. The cultivar you choose will determine the size, which means it’s wise to do your research before investing in this specie of plant, especially if you’re trying to fill a certain sized garden.

Garden phlox showcases dainty flowers with a total of five petals. These are arranged in dense clusters, or panicles, which range in size from four and six inches high and between six and eight inches wide.

The flowers boast a sweet perfume, and certain cultivars are embellished with central eyes in complementary colours. While most phlox feature rich green leaves, some boast variegated foliage, tinged with cream or yellow margins.

Bloom time

From July through to September is the typical bloom period for garden Phlox. If you wish to prolong the flowering season, opt for cultivars that have been specifically bred to flower earlier or later than the average Phlox plant.

These species tend to be categorized as early season, late midseason, and late-season flowering plants. To ensure you have phlox in full bloom all summer long and into the month of autumn, simply plant several varieties.


This species of plant boasts an impressive one hundred plus cultivars, which results in a huge range when it comes to planting height, panicle sizes, and flower hue. In recent years, even more, cultivators have been introduced to the market.

In fact, the Dutch have an ambitious breed, with larger flowers, colourful blooms, and much smaller plants, which are perfectly suited to containers and the front of borders. Certain American species are able to withstand common ailments such as powdery mildew and other foliar diseases.

Heirloom cultivars with slighter flowers are also making a comeback because they are similar to those that were once grown in Victorian cottage gardens.

Pros of the Phlox plant

  • These plants last a long time, yet despite this, they are still extremely low maintenance, which makes them a great option for new gardeners and those with busy schedules. They can last in the garden for decades when provided with the right growing conditions.
  • When many other perennials begin to fade, the Phlox continues to bring a hot hue to the garden.
  • They attract an abundance of wildlife in the shape of bees, butterflies, and hummingbirds.
  • They rarely require staking.

Things to watch out for

  • They can become susceptible to damage caused by powdery mildew.
  • Deer and rabbits tend to graze on these plants.
  • Although phlox are easy to sow from seed (certain species even self-sow), the offspring of a number of cultivars can vary in hue and are often different to the parent plant.

Growing your own Phlox plants

If you want to grow your own Phlox plants, what do you need to think about?

Light requirements: Although phlox flowers thrive when placed in full sunlight, they don’t mind a little shade, as they actually originate from native woodland plants. This is especially the case when they are grown in hot southern climates. For best results, try to give them at least six hours of sun exposure daily.

Soil: These species prefer moist, fertile, well-drained soil, with added organic matter or compost. Phlox favours soil that is a little on the alkaline side and enjoys regular applications of lime if your soil tends to be a little acidic.

How to plant: If you have chosen to grow potted plants or bare-root plants, it’s a good idea to place them in the ground in spring, post frost. For best results, position the plants around 18 to 24 inches apart, as this will ensure good air circulation. Once in place, thoroughly water, and apply a layer of mulch around the roots. This will help to keep them both cool and moist. If you wish to grow Phlox from seeds, you must grow them indoors initially.

Propagating: The simplest way to replicate garden phlox is by using the method of division. Begin by digging up the plants in early spring or late summer, follow this by splitting the clumps into sections using a sharp knife to do so, and then plant immediately. Each section should comprise at least three or four shots and a percentage of the root system. You can also use summer stem cuttings to propagate phlox.

Placing in the garden: Few perennials are able to withstand the weakening midsummer landscape like the garden phlox. They can be used in cottage gardens, in mass plantings, meadow gardens, as cut flowers, pollinator patches and in container gardens. They are a great option for those who wish to add an instant splash of colour to an otherwise subtle garden. Because this plant is available in various sizes, there is a variety to suit all gardens.

Watering: Phlox doesn’t do well in a drought and therefore should be watered on a regular basis, particularly during dry spells. If you notice the plant wilting, this is a sign it’s lacking in water.


Lily Calyx is our in-house flower whisperer, an expert on all things botanical and an enthusiastic orchids collector. She loves discussing the insights of the secret world of flowers, shares her gardening tips and hacks and moons over the latest additions to Serenata Flowers flower range. Ask Lily anything about flowers and we can guarantee she will have the answer.

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