I am having trouble with my garden and need some help.
I have a small back yard which is semi shady to sunny, with soil containing all sorts of rubbish. (The builder who did my flat dumped all kinds of things into the garden, like computer chips and juice bottles. I didn't know this till I bought the place and started digging the ground up.) Depending on the spot the ground is too well drained, or with too much clay. And I have SERIOUS slug/bug problems.
I have been digging the whole garden up and mixing up organic matters, or just generally airing the ground. It is getting better but I still cannot get it right. I am trying both organic/chemical slug-cides but it is JUST not working enough.
It's been over 3 yrs since I began my work on it, and every plant I plant into the ground simply doesn't grow well at all. Following were the only plants did OK;
(All grown from seeds.)
Heliotrope
Thunbergia
Nasturtium
Lavatera
Chives and Onions
Lavender
Following did OK in one year or another;
Lupin
Delphinium
Chilli (all sorts)
Blue Salvia
Following were SUPPOSED to be dead easy to grow, but failed!!;
Nemophila
Nemesia
Nigella
Larkspur
Hosta (bought roots)
They failed ones grew really small, or just dissapeared/died.
I am adopting methods of companion planting and green manure, but it is just taking so long and I am wasting so much money and killing so many seedlings.
Please give me a few ideas what I should be doing next...
like, is there any plants that is sure to grow in my garden of death?

And what can i do with bugs, bugs and bugs!!
I am trying mints now, but they are a bit boring...
Thank you for reading all of it and thank you for your comment in advance xx