I absolutely love planting narcissus every year. It is best not to
plant them until cooler weather sets in permanently, thus avoiding premature sprouting. I usually set them out after Thanksgiving, or after the first light frost.
I wouldn't cut off those sprouts, I'd just leave them be. You may lose a few blooms, but with colder weather just around the corner, I'd bet it'll stop them from
growing further and using up all their energy they should need for
spring.
Next time, I'd just set them out later, to prevent sprouts too early.
