So despondent- just pulled out a couple more dead shrubs. What am I doing wrong?

[RedPeeps4]

I've had my current garden about three years, and I'm still struggling with it so much. I've just pulled out a couple of dead shrubs that were planted in the autumn and didn't make it- a shrub rose and a wintersweet. So few things seems to thrive in my garden, what on earth am I doing wrong? I'm a middling experienced gardener, but I've never had a garden where so many plants seem to languish or die :(
The garden is a new build, with a typical builders rubble type soil which I've spent months improving. The garden is west facing- so the left hand side is in deep shade and infested with slugs and snails that decimate so many things, and the other side is baked south facing with very poor, chalky soil. I've pulled out wheelbarrows full of chalk and rubble, added endless manure and soil improvers, applied nematodes and fertilisers, and yet I've lost so many plants. On the plus side the wisteria and climbing roses I've planted seem fairly happy, so small wins I suppose... But those two alone won't make a garden! What on earth can I do, and what on earth can I grow that will thrive? I'm hoping the wise gardeners of MN can give me some advice and some hope!

Are you planting shrub resistant plants? Roses don't do well where roses have been planted previously.

I removed a huge wisteria a few years ago: in the same bed, Daphne and Hibiscus have done well. Also Penstemon for summer colour, and fuschias. An Oleander also thrives.

Nematodes in Feb help.

Is the soil still poor? Is the garden very exposed? What size shrubs did you buy? It’s always better to pay more and buy a decent size plant from a decent supplier. If you bought small plants from a supermarket then that’s your problem. They’re often poor quality and too small so they die.

Thanks so much for your prompt replies, I really do appreciate it! @RosesAndHellebores I've also lost both a Daphne and a Hibiscus in previous years- you can see why I'm getting so despondent! In previous gardens I'd just plant, water and feed, and plants would happily start growing without too much effort!
I've applied a couple of doses of nematodes so far this year, and the problem is gradually getting better than when I first moved in, when the lawn would literally be a sea of slugs on a damp summer's evening! 😫
However, it's still fairly bad, and I've never had a garden with so many slugs and snails. I read somewhere snails can be a bit more of a problem in a chalky garden?

@Maireade1 The soil in the south border is still fairly poor, although slowly, slowly improving. The soil in the north border is actually fairly decent now, but very shady and still ravaged by slugs and snails. The garden isn't particularly exposed, although the bottom of the south border does seem to sit in a bit of a frost pocket. In the last couple of years I've switched to buying more mature plants, generally from good suppliers such as Crocus. A mature Daphne and a mature camellia I bought didn't survive sadly.

Don't think camelias and daphnes are keen on chalky soils, maybe keep those in pots?

This page might be useful www.rhs.org.uk/plants/for-places/chalky-soils

For what it’s worth there seems to be an inordinate number of slugs and snails this year. I guess the long, wet, not very cold spring was ideal for them. I’ve lost plants they don’t usually give a second glance too. One even got in the house and ate my amaryllis and I found him on a cactus but he didn’t try to eat that.

What are you planting where? So are you putting in shade loving plants in the shady damp bit, & sun loving plants in the other part?

Hello OP, do not despair. There is a solution for every garden. I have had several very large gardens in different climates with different soils and expositions .
The first thing you need to look at is your drainage. It sounds like yours is not draining correctly and this will be the first thing killing your plants. Read up about drainage in a new garden.

Second thing is your fertilizer. It sounds like you have been using alot and probably way too much, especially if your soil is not draining. Stop fertilizing immediately! Plants should never come in direct contact with any type of fertilizer and any manure must be completely aged . This is a common mistake of novices.

Third is your soil. Did you have truckloads of new topsoil brought in to put on top of your rubble and chalky base? I didn't think so.

Solutions depend on the answers to the first three questions!
I think probably the best, easiest answer for all your problems would be to bring in fresh topsoil- purchased from a landscaper- not just any old soil will do. The more the better.

Have a landscaper come out and offer you advice. It would be worth your weight in gold ( well not quite) to pay for an hour or two of their advice for your specific garden. Mine is given freely and can be read about in any old fashioned encyclopedic gardening book.

Good luck and happy gardening! Please come back and tell us what worked. ;)

Daphne likes moist free draining neutral or slightly alkaline soil

Thank you all so much! I have been being quite careful to plant sun loving plants in the sunny spots, and vice versa, but maybe I've not being paying quite close enough attention to the chalky soil by the sounds of things!
I'm glad its not just me waging a never ending war against the slugs @Billybagpuss ! But I'm very sorry they came indoors to attack your houseplants!
I think you might be right @Whataretalkingabout , my usual method for planting something is to dig a largish hole, get rid of all the rubble, stones and lumps of chalk, and then backfill with a mixture of shrub compost and bagged manure from the garden centre. I've pulled wheelbarrows full of chalk, rock and rubble out in this way over the last few years- planting anything in my garden is quite an undertaking because of the amount of rubbish you need to get rid of first! Then in the winter I'm top dressing with more of the bagged manure and soil improver. I've not added any new top soil though, no. It sounds like that and improving the drainage might be the way to go. A landscaper sounds like a really good call- I've tried my best but it might be time to get the professionals in!

This is a common mistake of novices Maybe, but OP isn’t a novice.

I think this could possibly be the answer then. You are digging a large hole, and improving that area, but the surrounding soil is still rubbish. I suspect what's happening is that the newly-dug holes have a drainage problem. Either they are draining much faster than the surrounding soil and the shrub roots are drying out, or the exact opposite, and they are acting as reservoirs and holding too much wet.

Just a thought.

Oh yes, and a tip - when digging a hole for a shrub or tree, make it a square hole. Otherwise if it's a round hole, the roots can end up going round and round in circles like they do in a pot. If the roots come up against a corner, they are more likely to be able to break free.

The thing with bagged shrub compost is it doesn't have any clay in it like ordinary topsoil has. Most soils do better with a bit of clay because it retains moisture and plant food so soil doesn't die of thirst if it is in a hot and sunny spot. Of course your shady spots don't sound like they need help with moisture retention . Chalky soils are dead and lack nutrients...
Mostly I think you need some good healthy & living free draining topsoil .