You either: Try to improve the ground (by adding even more drainage), build your raised beds even higher to get away from it Plant in containers. Or put in more suitable plants.
If you weren't in such a tight squeeze you would put trees in, but I can see that won't go well there.
The other alternative to digging out and putting more drains in, or a sump, is to go the other way and make the beds higher, even if it's just at the worst end. Then fill with other organic matter like compost and rotted manure - not topsoil, which can be heavy and moisture retentive, and loads of fine gravel, all mixed together. Pea gravel is ideal, and pretty cheap. I've often used it for raised beds. You'll need to top up the beds regardless of what you fill them with, but the better the mix, the better the drainage will be. Then use shrubs or a small tree which will soak up excess water more easily, rather than perennials. There are some perennials/bulbs which will cope - Acteas for example, and Camassias, and you could have Fatsias if you like them. All fine for shade. The fence won't necessarily rot if there's a gap at the bottom of it, and the bed has a sleeper along the back, so if it's not in direct contact, it should be ok - for a good while anyway.
It's a place where beautiful isn't enough of a word....
I live in west central Scotland - not where that photo is...
Thanks for the advice from all. Think we'll look into getting the bed built higher, and filling it with the suggested materials instead of top soil. I'll also have a look at the plant suggestions and see what works - only problem with trees will be the roots and the amount of nearby buried structures (drainage, pipes and main sewer cover is directly next to that area, plus it's very close to the house and the shed is on the other side of the fence on the block paved drive) so I'll look at plants whose roots don't go so deep.
You could make raised bed much taller. Add a thick layer of stones below present ground level. Mixed grit with top soil to help drainage when filling the bed back up.
I'm sure others on here have more experience with wetland plants but I spent ages last year researching just that. Our bog area isn't standing water but it does get at least 100l a day and is always wet.
I have irises, Butomus umbellatus, Lythrum Salicaira, Pontederia cordata, Filipendula ulmaria, a couple of different carex, plus some. If you do go down that route, look for riverbank and pond margin plants.
Another vote for raising the bed height to at least 0.5m and mixing grit in with the soil and digging in gravel/hardcore with the soil underneath. I hope you can get it resolved.
The wood will last longer if you line the insides (sides, not base) with plastic. Old compost bags are the right sort of thickness. Maybe have some seep holes drilled near the bottom of the beds as it doesn't seem to be draining through the soil in the base, although forking it over and mixing in some coarse grit/stones or hardcore as suggested above should help.
Doncaster, South Yorkshire. Soil type: sandy, well-drained
The problem with 'just putting in bog plants' is - the soil will likely be sour, and will only deteriorate in that regard over time. Bog plants still need adequate drainage to thrive
I'm never keen on the 'layer of gravel low down' method. It would have to be a lot lower down than the plant roots, or else it's just a sump, and you can still have those roots sitting in wet conditions long term. There still has to be enough drainage for that excess water to get away, which is why a raised bed is always better, with a good growing medium that has grit/fine gravel incorporated. Weep holes will also help, and certainly lining the timber, as @JennyJ says. That will help to mitigate the constant contact with moisture.
It's a place where beautiful isn't enough of a word....
I live in west central Scotland - not where that photo is...
Posts
Try to improve the ground (by adding even more drainage),
build your raised beds even higher to get away from it
Plant in containers.
Or put in more suitable plants.
If you weren't in such a tight squeeze you would put trees in, but I can see that won't go well there.
Then use shrubs or a small tree which will soak up excess water more easily, rather than perennials. There are some perennials/bulbs which will cope - Acteas for example, and Camassias, and you could have Fatsias if you like them. All fine for shade.
The fence won't necessarily rot if there's a gap at the bottom of it, and the bed has a sleeper along the back, so if it's not in direct contact, it should be ok - for a good while anyway.
I live in west central Scotland - not where that photo is...
You could make raised bed much taller.
Add a thick layer of stones below present ground level.
Mixed grit with top soil to help drainage when filling the bed back up.
I have irises, Butomus umbellatus, Lythrum Salicaira, Pontederia cordata, Filipendula ulmaria, a couple of different carex, plus some. If you do go down that route, look for riverbank and pond margin plants.
Good luck getting it sorted, whatever you do.
I'm never keen on the 'layer of gravel low down' method. It would have to be a lot lower down than the plant roots, or else it's just a sump, and you can still have those roots sitting in wet conditions long term. There still has to be enough drainage for that excess water to get away, which is why a raised bed is always better, with a good growing medium that has grit/fine gravel incorporated.
Weep holes will also help, and certainly lining the timber, as @JennyJ says. That will help to mitigate the constant contact with moisture.
I live in west central Scotland - not where that photo is...