Look at that c u c u – like little hoods and cowls, maybe for playing peek-a-boo: “Cuckoo! I see you! I C U!” Which makes it a fitting collation of letters, because cucullate means ‘hooded’ or ‘shaped like a hood’, from Latin cucullus ‘hood’ (also related to cowl). It’s said like “Q ka late” or “Q cull it.”
When it’s said at all, that is. It may be colourful, perhaps even lexically lucullan, but it does not have a lot of collocations, especially in lay use. Kids in hoodies are not called “cucullate youth” by even the most self-regarding prose stylists (although if someone wants to comb the works of Conrad Black to contradict me, go for it). It is, rather, biologists who put it to use: botanists, for instance to describe the flower of the aconite, or entomologists, for example to describe the prothorax of the Ptinus.
But I think this word is too luscious to keep in obscurity, even if its pronunication is a bit vexatious. I would not cull it, and I do not think it is too late to cue its entrance – though we may prefer to allocate it to select locutions and to audiences that will look it up rather than assume, by its shape, that it is like ululate but with cucu instead of ulu. With a few looks and a little luck we could inculcate it and see writers putting on the dog with a cute cucullate Chihuahua or kidding around with a cucullate snowsuited infant or, who knows, calling on South Park’s cucullate Kenny.