Great white trillium is a woodland plant that bears white flowers in May - June. It had been growing in my old garden for 4-5 years before I moved and it flowered a single flower every year, but didn't grow any bigger. It survived moving to a new garden, but it hasn't managed to flower since. I might need to find a better place for it. It could possibly need warmer weather, it is accustomed to warmer summer in it's native habitat.