Digging new bog area.. plant advice req re depth..

[dan-fisher]

Hi, I've done the pond nearly..

Now the next project is the 3m x 1.5m bog area next to it. Any decent advice will be appreciated,

My question is i want the plants that promote birds ie have plenty of seeds to nibble. But how deep do i need to be for the plants i want (root dependant?) for the birds, insects and of course the anphibians.

Marsh marigolds i've read are good for bees and insects

What about purple loosestrife, water mint, certain types of irises???

Any others that the birds'll love???

Also, do i actually need drainage in the liner ??

[Lancashire Lad]

Yes, you will need to poke a few drainage holes in the bottom of your liner to let excess water escape - but having said that, any strong pvc sheet will do as your liner -because it doesn't matter if it gets punctured, so no point in buying expensive butyl. You need to ensure sufficient drainage to prevent anaerobic conditions arising, which will rot the plant roots.

You will need to dig out around 30 -45cm of earth and after fitting the liner c/w holes, backfill with a very humus rich mix of soil/peat substitute/ mushroom compost etc. etc. (there are several such "bog soil recipe's" on the web).

The Royal Horticultural Society actually advises building in a leaky hosepipe, spreading a layer of crocks or coarse grit about an inch deep over the hosepipe & liner, and then backfilling on top of that. This enables watering if needs be in very dry conditions down at base root level.

Not sure how the land level will be between the surface of your bog and that of the pond, but it is advisable to have the bog slightly lower if poss. Then there is less chance of nutrients leaching from the bog into the pond during wet weather. (Excess nutrients in pond is likely to create problems with algae/blanket weed etc.).

As for plants: -
Marsh Marigold, Purple Loosestrife, Water Mint, Yellow Flag, Stinking Iris, Some of the Primula's, Astilbe's & Hosta's, The list is fairly extensive. You might be best advised to visit your local garden centre(s) for advice, as to some extent the choice will be determined by your soil mix & type.

Regards
Mike.

[dan-fisher]

Thankyou mate,

I'm just using some damp proof membrane for the liner which i'll proberly slice some slits in with a stanley knife (plasters at the ready!). The membrane is cheap from jewsons or the like. But i've got some left over from a job.

The bog will be lower than the pond simply due to the slope of the garden, nutrients in the pond is something i don't need after the garden center told me to empty a bag of garden compost in it

The hose pipe i quite like for emergency watering, i'll cut a load of slits in it and bury it in there. The soil here btw is very dark and rich so i'm expecting to throw too much peat in there.

I'll dig it all out tomorrow so will see how it goes..