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The New Zealand flax is a great evergreen shrub that can add a lot of shape and decoration to your garden. It’s a lovely plant that gives you architectural shape and colour all year round but it does get quite large which is why regular pruning is important to maintain its shape and remove spent flowers and damaged foliage.
However, if you let it get too big for the space provided it will start to crush the other plants that might be grown nearby and at the same time take on a rather worn appearance.
When regular pruning is insufficient there is one solution that can really help reduce the overall size, dividing your plant. Plus you get the advantage of getting extra phormiums to plant elsewhere.
How to divide your New Zealand flax
These plants are very unique because they spread by forming new plants around the older plant so the process of splitting and dividing them and replanting them in other areas of your garden is fairly simple.
First, start by getting a garden fork and loosening the soil around the plant. If the leaves are already very floppy, you can cut off the outside leaves to the base or simply tie all of the leaves together in a bundle so that it’s a lot easier to deal with without getting poked in the face.
If you have a large plant you can try and slice and remove sections, if you have a smaller or pot-grown phormium, you can lift the whole plant and split this into several plants.
Once the soil is loose around the area, dig in with the garden fork or spade and get underneath the roots. Use your garden fork/spade to slowly lever it out of the ground.
You should start to see the plants fall apart into clumps at this point. If you don’t notice it falling apart into clumps, take a hand tool and work your way around the roots to try to prise them apart.
Remove as much excess soil as you can so that it’s much easier to replant and spread out the roots when doing so. Take one clump at a time, trim off the outside leaves as low to the base as you can and once you have neat clumps you can always cut the remaining leaves to about ankle height so that the plant doesn’t fall over when you try to put it in its new home.
After every clump has received its haircut, dig out an area where you want it to be, add some organic leaf mould or compost to the soil and replant your new sections, spreading out the roots as much as possible sideways and then firming it down on top. After a good watering, rest assured the plant will start to rebound and continue to offer long, spiky leaves for years to come.