Question
The mortar between my landscape bricks is either missing or in bad shape.  I think all I need is to buy some mortar and put it between the bricks.  Do I need to mix sand or anything with the mortar first?

Answer
Hello, Mike:

Mortar is a mixture of sand, lime, water, and cement.  There are different types based on percentages of how they all get mixed together; indoor, outdoor, water-resistant, etc.

Here are some web resources discussing the two main types, N & S:

1.)  What Mortar is:
http://www.essortment.com/home/mortarsandceme_szvs.htm

Now that you've got a batch, here is what you can do with it.
2.) If you want to lay whole bricks into new, wet mortar:
http://www.ehow.com/how_2216289_lay-bricks-wet-mortar.html

3.) If you just want to re"point" or re-grout your existing, crumbly-mortared bricks (I know it is a wall, but the concept is the same for a patio):
http://www.dummies.com/how-to/content/how-to-repoint-a-brick-wall.navId-323595,p...

It is a chore and a mess.  At the big-box stores (Home Depot, Lowes, True Value, Orchards, Southern Farm Supply, etc.) There are "patch" kits of small bags of pre-mixed mortar - except for the water part.  Kinda like ready-mix pancake batter....Never tried them, so I cannot recommend a brand.

Be sure to read the side of the bag to see what else you may need besides water & a wheel-burrow.

good luck!  ~Marc