By Gardenannie
United Kingdom 
What type of soil should I plant phormiums in
6 Sep, 2022
Answers
As Seaburn says, Phormiums are not fussy. You can plant them anywhere in your garden except beside a pond …
10 Sep, 2022
Welcome to GoY.
They don't seem fussy as long as the soil doesn't get waterlogged.
RHS say peat free compost and doesn't specify that it needs acid conditions.
lots of advice in RHS link below.
https://www.rhs.org.uk/plants/phormium/growing-guide
7 Sep, 2022