Basically, the first winter will be the hardest on them as they have not had time to adjust to cooler weather. It is important to keep them very dry and as warm as possible - such as under the eaves on the north side of the house. The leaves will yellow, but that is just a response to cooler temperatures, and will still be good for use in cooking. Some of the older leaves may even go a bit brown and die off. That doesn't matter, as long as the roots and growing tips are OK, they will sprout back when the weather is warmer.
Some people even bring them in the house over winter. A bright spot in the bathroom is ideal.
Pandan is used primarily in Asian cooking. It has a fresh, nutty and delicate fragrance and is popular in many desserts. Another trick is to cut off a leaf, tie it in a knot, and throw it in the rice cooker when you boil rice. The leaf is removed after cooking and it really enhances the taste of the rice.
Additionally, Pandan leaves can be thrown in a kettle and made in to a tea (very much like tea leaves). The only difference is that Pandan is best used fresh and does not have to be dried.
Pandan has various non-cooking uses too. A leaf tied to the airconditioner in the car will provide a nice fragrance, and the leaves are often left in wardrobes to absorb bad odors while simultaneously releasing an attractive one!
If you are interested in Purchasing a large Pandan plant here in Sydney, please contact me