Pruning phlox is not mandatory, but it does have a number of benefits. Find out which ones and when and how best to use the cutting tool.
In a nutshell
- Prune phlox to encourage re-flowering (remount)
- correct pruning time crucial for new growth
- always use cleaned cutting tools
Best time
There are various “right” times when pruning flame flowers is advisable. Below we tell you when you should cut phlox.
Flowering time of the phlox
The best time to stimulate a rebloom or second bloom is just before the onset of flower wilt. Even if cutting it off is difficult due to the still beautiful-looking buds, this point in time should not be missed. As the wilting progresses, the seeds form. The plant invests a lot of energy for this, which is then lacking for renewed flowering. The following should be observed when pruning flowers:
- use disinfected, sharp cutting tools
- Start cutting before the first leaves
- During the main flowering period, look out for signs of wilted flowers at least every two days and remove them if necessary
fall cuts
Prune a phlox in the fall when it is weakened after an illness or pest infestation. Theoretically, the annual pruning can also take place here if the wood has withered by then. This usually only applies to varieties whose flowering period ends in July or early August at the latest. Numerous branches also die off in the tall perennial phlox (Phlox paniculata) and the large-leaved phlox (Phlox amplifolia) and can be cut out in autumn. However, it offers an ideal place for hiding and as a winter quarters for all kinds of animal garden visitors. In addition, the dead plant parts form a natural protection against the cold for the roots.
Autumn and winter green varieties
Phlox varieties that bloom into late summer or fall and/or stay green through the winter months should be planted in the fall not get cut. Your branches are too fresh. Because of the cold and usually high humidity, there is an increased risk of fungal infections. In addition, cutting weakens any plant that should collect its energy for the winter.
Tip: Cut the flowers of autumn bloomers shortly after they begin to wither to avoid seed dispersal in the garden and subsequent unwanted, uncontrolled overgrowth. However, this means that it will flower again in winter not to stimulate
Phlox paniculata 'Autumn Waltz' - Autumn bloomers
spring cut
Spring is the best time to prune a phlox. Important details should be noted here:
- cut just before the start of vegetation (usually between early February and mid-March)
- do not cut earlier, as phlox flowers need the hibernation
Occasional clipping
With all Phlox species, it occasionally happens that parts of the plant die off or dry up. These can be cut out anytime between early spring and late fall. This ensures a more cultivated overall picture, while promoting branching and, ideally, new growth for more flowers.
cutting technique
The correct pruning technique depends on whether it is a winter or deciduous phlox species. Although both are about stimulating new growth, a different cutting technique is required:
- Cut back wintergreen species by two thirds
- Cut withered phloxes to a hand's breadth
Always use disinfected & sharp cutting tools that have been cleaned before use.
delay flowering
If the flowering time of your phlox is too early for you, you can delay and postpone the start of flowering by pruning. This makes sense if the earlier flowering splendor cannot be enjoyed, for example due to a holiday. The cut is made before the buds form. With the right pruning technique, there is increased branching. New buds form on the new branches and consequently the flowers appear later. This technique was "discovered" in England and is referred to as the "Chelsea chop technique".
The following should be taken into account:
- Best time: late May to early June
- Shorten shoots by a third
- Delay period: between four and six weeks
- exclusively applicable for high flame flowers
Tip: With the special pruning technique, you can not only delay the formation of flowers, but also extend the flowering period. To do this, cut off only a few shoots so that part of it blooms at the regular time and this is followed by the delayed flowering.
Cut creeping phlox
A special feature among the phlox species are the ground-covering variants: upholstery or carpet phlox (Phlox subulata). With a maximum growth height of between 15 and 20 centimetres, there is not much room for cutting. However, it is advisable under certain circumstances.
cutting instructions
In the case of the flame flower species that grow like a lawn, renewed flowering is also possible if the old one is cut off when visibly beginning to wilt. However, an annual pruning is not necessary, as is recommended for high flame flowers. However, the ground cover thins out over the years. Usually this starts from the middle. To prevent this, a so-called rejuvenation cut or radical cut is recommended at regular intervals.
- Cutting rhythm: every two to three years
- best time: spring before new shoots begin
- radical pruning back to a third or just under the breadth of a hand
Liquid fertilizer in small doses
So that the ground-covering phloxes quickly form new side shoots and thus become more extensive again, you should administer a suitable liquid fertilizer in small doses after cutting. This promotes the growth of lateral new shoots in particular.
frequently asked Questions
Can phloxes that die above ground be saved by pruning?As a rule, they do not need rescue. The death of above-ground plant parts is normal for many Phlox species throughout the winter. In spring they will sprout again as usual. However, it is advisable to cut off the dead remains in early spring so that they do not spoil the appearance.
How to prune a carpet phlox for denser growth?If you want your carpet phlox to grow denser, prune it as described in this article. This cutting procedure serves to prevent light spots as well as to stimulate denser growth. If necessary, a pruning can be done every year. With an average growth rate of about ten centimeters per year, your carpet phlox will quickly regain fullness after cutting.
What happens if the phlox is completely cut in the fall?Usually nothing - at least not for the species that bloom during the summer months. However, if you cut off fresh parts of the plant, there is an increased risk of infection as well as the risk of frostbite. In the worst case, frost pulls through the plant sap to the roots and the flame flowers die off. Therefore, dead parts of the plant should be cut off in autumn. It is always better to wait until spring.
When to cut a phlox after transplanting?After transplanting, you should definitely wait until the roots have hardened before cutting. Only then is an optimal supply of the plant possible and it can easily withstand the strain of cutting. Since transplanting should never be carried out when the flowers are in full bloom, this time is also omitted for subsequent cutting.