Thanks so much for the reply. I'll try the leaves. The oil spray sounds positive, though it seems it might gunk up the mattress after a while.  Then again, gunk might be better than those pesky, all-prolific dustmites. (You don't really want to think very hard on how many ounces of them are living you your bed).  ( :   
And thanks for the tip on chamomile.  Allergies are so unpredictable.