Phlox: expert tips on planting, care & propagation

Sarah
Sarah
Sarah
Sarah

For me plants are some of the most exciting living beings, even though they live in slow motion. They have fascinating abilities and just so much potential! That's why I studied organic farming. However, since plants are rather thin on the ground in my city, I often spend time hiking in the nearby mountains at the weekend. In the future I would love to run a farm myself.

Favourite fruit: strawberries and gooseberries
Favourite vegetable: courgettes

Phlox should not be missing in any cottage garden. Here, you’ll learn everything you need to know about planting, propagating and caring for phlox in the garden.

Butterfly inspecting phlox flowers
Phlox not only looks beautiful; it also attracts butterflies [Photo: Halina Pawlak/ Shutterstock.com]

The real beauty of phlox (Phlox) is its wonderful summer scent. It not only captivates us humans, it also attracts numerous butterflies.

Phlox is an asset to any garden. By opting for phlox, you do something good not only for your garden design, numerous insects will also thank you, because phlox is a excellent nectar plant. It blooms a lot, but also for a long time.

Phlox: origin and characteristics

Phlox belongs to the so-called celestial plants (Polemoniaceae) and is also called flame flower. Phlox is as beautiful as its names suggest. The plant originates from North America, Asia and parts of Russia. There it grows in different climates, which is why many different species of phlox have developed. And quite a few of these have long since made it into our gardens. The plants come in a wide variety of shapes: Large or small, elongated or creeping on the ground. They all have in common the fact that they are herbaceous and are conspicuous for their characteristic flowers. Most phloxes are perennial and can easily survive cold winters.

Phlox species and varieties

Phlox has over 70 species. And ever since it came to Europe as an ornamental plant in the 18th century, numerous new varieties have been bred. Thus, today the choice of the most diverse species of phlox and varieties is extraordinarily high. Many of the species bloom throughout the summer in shades of white, red, pink and purple.

Cut phlox in a vase
Phlox also make quite a statement as a cut flowers [Photo: Svetlana Gorbacheva / Shutterstock.com]

Phlox paniculata

Garden phlox is probably the best known of the myriad phlox species. It is native to North America and reaches a height of up to 1.5 metres. This makes it a popular companion in many perennial beds or cottage gardens. It likes damp and sunny conditions.

Garden phlox with pink flowers
Perennial phlox are the most frequently planted phlox species

Learn more about the summer perennial Phlox paniculata here.

Phlox subulata

Carpet phlox is hardly comparable to garden phlox, which is considered the quintessential phlox. Carpet phlox, as the name suggests, grows in width rather than height. It loves walls and sunny ledges.

Pale purple phlox flowers
Creeping phlox can also be planted over large areas as a lush flowering ground cover

Phlox drummondii

Summer phlox is an annual phlox species. It is widespread in Texas as a wild plant and is popular in this country as an ornamental plant. It only reaches a height of up to 50 centimetres.

Phlox amplifolia

Large-leaf phlox is quite similar to garden phlox. It also grows up to 1.5 metres tall. Its most important distinguishing feature are its significantly larger leaves. In addition, it is less susceptible to drought, pests and diseases. It is therefore always suitable where garden phlox does not quite thrive.

Phlox stolonifera

The so-called rambling phlox is also suitable for shaded areas as a ground cover. But do not worry – it does not spread uncontrollably and can easily be kept in its place. It blooms in spring and early summer, so feels comfortable, for example, under deciduous shrubs in the garden. Sufficient light still penetrates there early in the year. Rambling phlox also likes to grow along shaded walls.

Moss phlox among rocks
Moss phlox is a pretty ground cover and thrives in shadier areas [Photo: Isabel Eve/ Shutterstock.com]

Phlox divaricate

Forest phlox grows as expected, even with little light. It blooms in early spring and feels comfortable, for example, between towering perennial plants. Forest phlox also gets along well at the edge of the forest and under deciduous trees and shrubs.

Phlox douglasii

Cushion phlox is the right phlox species for rock or rooftop gardens because it loves the sun. The plant grows like a cushion over everything that gets in its way, growing only about 5 centimetres tall. It blooms in May and June in a wide variety of purple hues.

You can learn the most important things about the small Phlox douglasii here.

Pink carpet of phlox flowers
Tufted phlox shines in vibrant colours and copes well in drier locations [Photo: Angela Rohde/ Shutterstock.com]

Planting phlox

Planting phlox is not complicated, but there are still a few things to consider. While some species of phlox prefer a sunny location, others like more shade. Plant phlox as a free-standing plant, so that no mildew can develop and keep cultivation breaks.

Everything else that is important for planting phlox can be found here.

Phlox inflorescences beginning to bloom
To keep phlox healthy, give it a growing break before replanting [Photo: haraldmuc/ Shutterstock.com]

Propagation

Phlox can be propagated in three ways: Either directly via cuttings or by division. If you leave withered flowerheads, propagation via seeds is almost guaranteed.

Learn here what to consider when propagating phlox and how best to do it.

Plant care

Phlox is easy to care for and uncomplicated. However, to bring it to full bloom, you should give it a little support.

Here, we show you how to care for phlox so that it thrives.

Watering phlox

Water requirements vary greatly by species. As a rule, phlox does not require much watering, except before and during flowering. However, keep in mind that species suitable for rock gardens usually have lower water requirements, but can also colonise a much drier site.

Fertilising

A starting dose of a slow-release fertiliser such as our Plantura Flower Food will help the phlox get going and provide it with optimal nutrients. Alternatively, you can also add compost or manure as fertiliser to the planting hole. To really boost flowering, you can also add a portion of fertiliser just before flowering.

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Pruning

Phlox, in principle, does not require pruning, pruning is mainly for the rejuvenation of wintergreen species. Removing wilted flowerheads after flowering offers the advantage that the plant will not self-seed. If you do not mind an increase in phlox, you can safely leave the flowerheads and enjoy even more phlox next year. Otherwise, in the case of deciduous phlox, the dried shoots need to be cut in autumn.

You can read here what needs to be considered when pruning phlox.

Overwintering phlox

Phlox is generally hardy and does not require special attention before winter. Although the above-ground parts of the plant die over the cold season in many species, they resprout in the spring.

Tip: Leave dead shoots until new shoots appear in the spring, so insects like wild bees can find a place to hibernate.

Common diseases and pests

To prevent infestation with diseases and pests, you should use fertilisers with low nitrogen content. While nitrogen is absolutely necessary for plant growth, too much leads to increased plant susceptibility.

Basically, only a bright and well-ventilated location helps against powdery mildew (Erysiphe cichoracearum), because powdery mildew likes it damp. The fungus is easy to spot because it covers leaves and stems in a whitish-grey coating. The large-leaved phlox is more resistant than the garden phlox.

Phlox leaves covered with mildew
Powdery mildew forms unsightly coatings on phlox leaves [Photo: Tunatura/ Shutterstock.com]

A second group of fungi is also not averse to phlox. The fungi of the Ascochyta and Septoria group cause so-called leaf spot disease. As the name suggests, this causes unsightly dark spots and dots on the leaves, which later lead to leaf drop. As with powdery mildew, a common cause is excess humidity. An airy location is therefore also helpful. However, make sure not to water the plants from above to avoid wet or soggy leaves. In the event of an infestation, be sure to cut back all infested plant parts and burn or dispose of the resulting green waste in your household waste.

The third most common pests of phlox are stem nematodes (Ditylenchus dipsaci). The longer the plant grows in the same place over and over again, the more pests such as stem nematodes multiply. They rob the plant of strength and energy and cause stunting of leaves and shoots. The only thing that helps is to temporarily change the location. The best option here is to replace infested plants by propagating cuttings.

How cutting propagation works and other methods for propagation of phlox can be found here.

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