We at Select Plus have taken a the decision to not use any herbicides or pesticides on our lilacs as of 2005. 
We manually pull weeds from pots and take care of any pests with natural products or manually when possible. 
We encourage these cultural ways to produce plants to the home gardener and even to other nurseries. 
We are proud of our achievement and decision. 
So in the event that you find the odd weed in a pot or shipment just remember it's for the environment.

As of 2009 and things we never mentioned
We will be monitoring watering schedules more
We have always used recycled boxes
We will no longer use styrofoam chips as filler. Shredded newspaper only
We reuse the pots the plants were grown in
We reuse shaken soil from container plants for our gardens
We offer on line catalogs for saving on your computer
We have strictly cut down to an absolute minimum printing catalogs