I have a big stand in what is mostly full sun. It flowers prolifically and has almost from the minute that I put it in (photo attached - poor quality so I put a circle around the full stand). It also reproduces prolifically. A bit of a nuisance since its spininess makes it nasty to pull out. I love it because of its structure and the bronzing of the leathery leaves in winter - many turn almost black. Agree with comment above that the flowers on the named cultivars are more interesting and dramatic. All of those I have to grow in almost full shade, though. I'm in a vastly different climate than you are, but my sister in VA outside of Washington DC grows the cultivars in full shade and they bloom. This one has been renamed Berberis aquifolium, fyi. Berberis aquifolium - nine years after planted as #1. Taken a few weeks ago.

Curious that the Mahonias are doing well here too. The lovely winter flowering ones are long finished. I usually find M aquifolium very dull, possibly because its used as a boring filler in gloomy woods and shrubberies but this one impressed even me. It was about 6 feet high. But the scent is nothing compared to the Winter ones. Picture taken last week.

Not enough information. Where are you located in the world? What sort of Mahonias? How did you treat the shrubs? Any chance of pictures? You might find more action over on the shrubs forum. This one is pretty moribund.

As I stated previously, it is one of the Asian species or a hybrid thereof. And I don't know what you mean by "less horrible"..........no mahonia is necesarily 'horrible' :-) Some may be invasive under certain circumstances or in certain locations and none are grown specifically for their fruit, which has little appeal to anyone other than wildlife, but I would hardly define either of these attribute as 'horrible'! btw, I would not consider anything coming from The Spruce as "authoritative". It is a lifestyle website (formerly known as About.com) that employes all manner of writers for their various articles, some very knowledgeable and others not so much. Inaccuracies, wrong information and misidentifcations are common. If you want something authoritative on plants or gardening, stick with the .edu websites or those that focus only on plants and gardening like MOBOT or Monrovia or The Morton Aboretum, etc. And even those are not a 100% guarantee of accuracy or up to date info.