Our site is reader supported, this means we may earn a small commission from Amazon and other affiliates when you buy through links on our site.
Phormiums are very strong plants perfect for windswept Gardens or coastal areas. These are no tender houseplants and they can easily tolerate -5 degrees C easily, even -10 degrees C if you take some precautionary measures such as putting a good layer of mulch around the base of plants in winter as many people in the Uk learned in 2013 when a very old winter killed many phormiums in gardens across the Uk and Ireland but this could have been avoided for most but we can learn from these mistakes.
As just mentioned, all they need is a lot of dry mulch around the base and in between individual shoots if you have a lot of side shoots. Having large clumps of mulch gives a degree of protection even if a large clump of mulch gets moved about by the wind. This gives you very simple protection against harsh weather and if you learn just one thing from this growing guide, this should be it.
How to grow Phormiums
Plant in fertile well-drained soil where possible
Phormiums grow best in full sunlight but will tolerate semi-shade too. They need moist, well-draining soil. They will perform in many types of soil that are otherwise considered poor soil as long as you add granular, nitrogen-based fertilizer on a regular basis during the growing season. These are very greedy plants so if you feed them well they will grow incredibly fast.
Many varieties and colours to choose from
You get a beautiful display of colourful foliage no matter the variety you choose not just in the leaves but in the flowers and the seed pods once they are of a good size. The leaves have strong strips that look like colourful rainbow bands of yellows, reds, greens, and oranges running up and down depending on the varieties of which there are many to choose from. The flowers are rich red and the seed pods are a hunter green.
Propagating Phormiums by division
Phormiums are so strong and hardy that you might find you want extra plants in your garden in which case you can easily propagate by dividing a strong plant in the springtime and they are probably one of the easest if shrubs to propagate and they literally propagate themselves.
How to divide phormiums
When you go to do this you want to dig around the plant so as to not cut into the roots and then gently pry away the side shoots from the main clump.
You will notice the side shoots immediately as they will have developed their own routing systems. You can easily transplant them if they have their roots into smaller pots such as 9cm pots and then keep them for a year in those smaller pots in a greenhouse or in a warm area with indirect sunlight such as a cold frame. Once they establish themselves you can move them back outside.
Dividing pot grown phormiums
You can also use the same process for phormiums grown in pots by simply removing small side shoots and potting them into your own pots. If you only have large pots you can also plant two or three baby plants into one pot and they will be happy.
Pests and diseases
These are so strong that they’re generally pest-free which is the good news, and those they get don’t usually cause many problems and are easily treated.
Even rabbits seem to walk away. One thing that can happen if you have an older plant is that mealybugs can make there home around the base but most of the time if you grow them outside any regular birds and other wildlife that comes to your garden will control the pest problem naturally.
If you grow them in pots or containers and you have an issue with mealybugs a can change the aesthetic appeal of the plant in which case you want to squash the bugs by hand or treat them using an insecticide.
Remember that mealybugs lay large quantities of eggs inside of your foliage space so you might have to use an insecticide regularly to get rid of the issue.
No matter what, Phormiums are an incredibly easy plant to grow and you get so many colourful leaves among the different varieties. Anyone who lives along a coastal area and is struggling to get something to grow should absolutely turn to this one as it will remain strongly in place even spacing the UK frost. Just don’t forget to add a good layer of mulch around the base for winter, especially if the forecast is extreme like it was back in 2013.