Bark

In my experience a membrane in a flower bed is a PITA. If the bark is deep enough any weeds that do come through are easily pulled up mainly because their roots are not too much in soil. Without a membrane you can use a hoe and just pull the bark back.

You may find to get a adequate thickness you need a lot more bags than you originally estimated. Bark will rot down and needs topping up, probably on a annual basis.

Where I have used bark it has been effective in keeping 90% of the previous weed cover in check and where weeds have come through I weed quickly with a hoe.

If you think a membrane under bark chippings makes it difficult, try a layer of membrane (sometimes two layers!) with a 5cm layer of pebbles over it! That was put down by the previous owner probably 20 or 30 years ago. It /used/ to suppress the weeds, but of course two or three decades of leaves rotting have led to a fertile, very stony "soil" with excellent drainage which weeds just love.

It is impossible to weed using a hoe on clay soil covered with chipped bark. The hoe gets caught on the larger chips and just bounces off instead of penetrating the soil. I've given up trying to hoe my clay soil since I put loads of bark chippings on as a mulch to stop it drying out so much.

Do you have blackbirds in your garden? Other birds probably do it, but blackbirds seem particularly skilled at moving bark onto adjacent paths, lawns etc.

Bark very quickly harbours a lot of blackbird food.

I have chippings over membrane and find that it needs to be lifted and sieved to remove the blown soil about once every five years.

There is at least 50m^2 of pebble-soil! With a depth of 5cm, that' would be about 5 tons to lift and sieve. That's a lot of work in itself, but I find the leaf mould acts as a weak adhesive too, so even trying to get the pebbles apart is hard work (which has been necessary when planting new shrubs). Anyway, many of the shrubs are now mature and blocking out much of the light beneath them, so most of the weeds only have a chance on the periphery.

We do that job with a battered old cement mixer purchased for a few pounds , shovel the pepple,gravel, bark, dirt mixture into it with some water and running it for a while, emptying water then a repeat rinse. Then poured out onto sieve made from metal mesh attached to a frame that is sized so it will fit on top of the wheelbarrow. The stones go back into place cleaned and the muck placed in places where it can dry out and eventually blend back into plain soil . I don’t like them because IMHO they belong on graves but a friend borrowed the set up to clean his white coloured chippings that had turned green over time and they came out after the rinse looking like they were freshly delivered.

The “garden mixer”is also useful for just breaking down ordinary soil which here is chalk and flint and sieving into the barrow for the missus pots ,sometimes it goes back into the mixer to be blended with some purchased growing medium, takes quite a lot of backache away from the task. GH

No, and experience suggests they are about as useful as a chocolate teapot anyway. NOTHING keeps weeds down except weeding. Bark being loose, makes weeding easier, that's all., Windblown seeds will still germinate on/in it

A cement mixer can make a handy rotary sieve.

Suitably sized tube of steel mesh clamped to the opening.

Load with stone mix. Position your barrow to receive the stone and set the mixer going. Sadly you still have to do a lot of shovelling:-(

I see GH has a different version!

I have six tonnes of chippings, which is why I pay somebody else to do the job :-)