I have been using grounds as top dressing for tomatoes, garlic, onions, blueberries, roses, hibiscus, iris, strawberries, and evergreens for years, with great results.
I use a "tea" of 1 coffee can-full (2lb can) of dry grounds in 5 gallons of water. I mix it Tuesday night, let it sit in the sunny backyard until Saturday, then strain it into my sprayer & give all the trees & flowers a heavy misting Saturday and Sunday afternoon, when the air temp is in the 70-80°F range. I also use this on the indoor flowers, and have no problem with them. It seems to perk the plants up, especially the apple and nectarine trees. Grandma said it was the caffeine, and I learned long ago that Grandma was usually right.
I put equal amounts of grounds, dry leaves, and grass clippings on top of the worm bed, and they tend to disappear very quickly. We have both Georgia Reds and 'Crawlers in the bed, and they both seem to be very healthy.
Every six weeks or so, I spread grounds on the grass (Scott's Drop-Spreader on #3), and I've noticed the grass seems to grow somewhat faster for the next month or so. It may be due to the grounds' properties, the increased worm activity, or maybe both.
Interested in others' findings.