Garden stil severely waterlogged. Bog garden?
It's still waterlogged in summer. Not as much as now, but still enough that it would be too wet for most plants.
There is waste ground behind my house that is waterlogged all year, and a bog nature reserve 10 minutes walk away. I just live in a boggy area.
west central Scotland
You can work with it
- wet, soggy ground is standard fare in this part of the world
The best solution is to do some research on plants which will suit, rather than just sticking stuff in. Some things - like flag iris, will grow in any wet ground without any help, but they also get thuggish. Loosestrife is the same. Other plants will need soil that isn't sour.
You also don't say whether the aspect is light and bright, or shady.
Check all those things first, before buying anything.
It's a place where beautiful isn't enough of a word....