Are grains of paradise necessary in my Delirium Tremens clone?

Hi guys, I'm brewing a Delirium Tremens clone tomorrow night and the recipe calls for 1/2 tsp. of grains of paradise in the last 4 minutes of the boil. I haven't been able to locate the spice and probably won't have time by tomorrow night? Is that really a necessary ingredient? I don't want to postpone my brew plans but will if this ingredient is that important to the flavor profile. Is there a substitute spice that will work just fine? Thanks

Half a teaspoonful in a 5 gallon batch is not very much in terms of flavor impact. Can you get your hands on some white or green peppercorns? Those would be a decent substitute.