How many rose gardeners does it take to change a lightbulb?
One, but if it doesn't start producing light soon enough they're pulling it out.

How many rose breeders does it take to change a lightbulb? As many as it takes...first they need to agree on whether its a new class of lightbulb or not.

How many rose triallers does it take to change a lightbulb?
Sorry, that particular lightbulb is not available for retail this year or in the forseeable future.

How many rose growers does it take to change a lightbulb? One, but you can't predict the demand for lightbulbs so please indicate whether an alternative is acceptable.

How many nursery owners does it take to change a lightbulb?
Lightbulb...whaddayamean its not a lightbulb...the tag says it is.

How many rose enthusiasts does it take to change a lightbulb?
One to gather the lightbulb, one to exhibit it and a whole society to sniff, gather and talk about it.