PHORMIUMS (New Zealand Flax)
Visiting Southern Ireland this spring it was soon apparent that the last winter had decimated most of the phormiums and cordylines both in peoples gardens and in municipal plantings. In Cornwall we clearly did not experience anything like the temperatures in Ireland which were as low as minus 15°C in January and February and our phormiums have survived. However from correspondence with Burncoose Nurseries customers in the North of England they too have lost many of the phormiums which have thrived in their gardens for the last 20 years.
There is therefore a risk that many people will decide not to replace their plants and try again. The purpose of this short article is to demonstrate that they should!
Phormiums are not tender greenhouse plants and they are especially good plants for coastal and windswept gardens. They can easily tolerate minus 5°C and normally minus 10°C (minus 12°C) if basic precautionary measures are taken. All that is necessary is a deep and dry mulch of peat, leaf mould, leaves or bark right around the base of the plant and between individual shoots if you have a large clump with many side shoots. The leaves of larger clumps provide a degree of protection, even if they do get split and scarred by the wind, but if we are presented with winters as cold as the last two then additional protection is necessary. Had such simple common sense steps been taken in Ireland or in the North of England then many more people would still be enjoying their phormiums now.
Phormiums require full sun in a moist but well drained soil. They will however grow well in poorer soils providing they are given regular granular feeds of a nitrogen based fertiliser. Phormiums are greedy plants which grow quickly if they are well fed. It is because phormiums provide such a quick and colourful foliage display that so many councils use them on city roundabouts and roadside plantings.
Phormiums are most easily propagated by division in the spring. Simply dig around the plant and gently prise away some of the side shoots from the main clump. The side shoots will have developed their own root systems and care should be taken to ensure that the offsets do have some roots with them. If these are small and inadequate pot them on and keep them in the greenhouse for a year while they become established enough to be returned to the garden.
3. Putting into small pot
4. Carefully splitting larger clump
7. Filling around edges with compost
8. Gently pack compost around plant to support it
4. Pests and Diseases
Phormiums are pretty much pest free and rabbits seem to ignore them. Mealy bugs can colonise on the bases of the shoots especially on other plants. Outside in the garden birds usually control this pest naturally on their own. When phormiums are grown in pots on patios or in the garden the mealy bugs can however appear unsightly. They can be squashed by hand or killed with a conventional insecticide. However since mealy bugs lay large quantities of eggs within the foliage spikes treatment may have to be repeated regularly. The best solution for a mealy bug infestation in a greenhouse context is simply to stand the plant outside and let the blue tits have a feast.
Phormiums are easy plants to grow and the range of coloured leaves between different varieites is enormous. Anyone who has experienced a failure after last winter should try again but remember to mulch heavily before the onset of a hard frost.