Question
I was browsing through a book from a grower in Vermont, they are advertising NZ Flax--I live in New York State bordering NY,NJ & PA, some maps say zones 5,5b,6. I am curious if you can shed any light on this plant ie: does it spread,will it survive in my area, any info appreciated. I don't know if I would be making a good or bad choice, it would add color, but pricey!  

Answer
Phormium tenax and P. cookianum are both called "New Zealand Flax", often called "Phormium".  Neither is related to the azure-flowered midsummer bloomer "Blue Flax", Linum perenne, or any of its Linum relatives.  P. tenax is better known and more common.

Some Phormium varieties are tougher and hardier than others, but generally, although all are reliably hardy only to Zone 9, they are said to survive a Zone 8 Winter if not weakened during the Summer by drought or other stresses.

New Phormiums leaves grow from the root crown at the center of the plant; established specimens resemble Daylilies (Hemerocalis), to which they are related.  Zone 8 is a Southern climate, milder than anything you will find in Vermont.  I would like to know if they are growing these Phormiums outdoors as perennials; if so, what varieties are they and what kind of location are they living in.

Many gardeners test the limits of their garden with plants outside their Zone; you would not be the first to grow a Zone 8 plant in a Zone 7/6 landscape.

Gladiolas and Dahlias should never survive on Long Island, but most of mine survive every winter.

If you can afford to be wrong, it is definitely worth giving it a shot.  Just try to maximize the odds in your favor by giving risky plants excellent drainage, planting within a few feet of a concrete foundation or structure, and providing a full sun exposure for winter warmth.

As for the "pricey" part, shop around - I don't know what this Vermont outfit wants to charge you, but you can always shop elsewhere.

Thanks for writing.  Keep in touch.