Wild lettuce (Lactuca virosa) also known as opium lettuce is renowned as a pain reliever that has been used for 100s of years.
The white sap may deliver similar effects as opium — but with fewer side effects.
Used as a sedative and pain reliever and has been used to treat different ailments and I suggest you google wild lettuce benefits, as there are many.
There are several ways to prepare this, the extract you are after is water soluble, so 1 tablespoon of chopped leaves steeped for 10 minutes or so in hot water. It is quite bitter, but you can add honey. 
It is most potent when flowering when it sends all its goodies to the top of the plant. Very relaxing. It can also be smoked, again google your own info on this. 
This is a bi-annual, so it will flower and self seed after the 2nd year.
All lettuce has some anti-inflammatory and pain killing abilities but this is much more potent.
You can also go online and see how to  make a decoction for an even more potent effect. You can also dry the leaves.
This should not be consumed if pregnant or breast feeding and you are to do your own research on this wonderful, must have (in my opinion) medicinal plant in the garden. 
Sale is for 50+ seeds
Can grow to about 1.5 metres. I find them very hardy.
Allow this to go to seed and you will have them popping up all over the place, just pull out any you don't want. They are only mildly prickly to handle, I've never felt the need for gloves. 
A very important addition to any garden especially in these precarious times it is good to do as much as possible to be able to look after yourself.
I only post on a Monday and express, so plants reach their destination before the weekend.
Sorry, not to WA or TAS.
I do combine postage, so please contact me for multiple purchases.