Please help. Planting ideas for south facing, heavy clay soil garden.

[AmusedMaker]

We have an almost 100ft garden on the outskirts of London. Extremely clayey ( have I just made up a word? ) it’s so bad that rain water just sits on it for days. It’s like a swamp.
Is there any hope?
We can’t afford expensive re digging and bringing in all new soil so hoping to work with what we’ve got.
At the moment there’s literally nothing in the borders as everything I plant never seems to survive for long.
Any advice welcome.

Clay is actually very fertile. In my garden (also clay) the following plants thrive: lupin, lavender, snapdragon, pelargonium, marigold, dahlia, peony, poppy, echinacea, roses, gladioli, crocosmia, snowdrops, tulips, alliums, daffodils, hollyhocks.

ThisUsernameIsNowTaken - thank you. 🙏

Those patio roses -a shorter ground cover type- did well in my daughters.

Is there anything in the garden currently? Trees / shrubs? When I moved in my new build garden the clay was so compacted it held the water like a swimming pool.
I really dug everything over, broke it all up (hard work), then planted trees and shrubs that help to draw up the water and are a good framework for the rest of the garden.
All the plants @ThisUsernameIsNowTaken mentioned above do very well in my garden too. Plus lots of others.

I’ve also had huge success with agricultural gypsum on my clay garden.

It’s for sale with brand name “clay breaker” but you can get it cheaper in bulk from farm suppliers as agricultural gypsum (and you do need quite a lot).

I dug it into freshly dug borders, and sprinkled it straight onto the lawn after aeration (so it goes into the holes and gets further into the soil).

It works best over winter when it can freeze and thaw several times as that’s part of how it works.

Its made a massive difference to the consistency.

As suggested above, I also planted trees, hedging and shrubs to help with water-logging. This is twofold- both for them to directly take up the water, but also for the root systems to help with drainage and decompacting the soil.

Also on heavy clay and my list of what thrives is very similar! I'd add Rudbeckia and perovskaya as wins as well. I'm afraid it's a lot of trial and error and I've probably wasted loads of money but I try to grow from seed to minimise the expense a bit and once you find something that works you know you can duplicate it.

The problem with going for plants that thrive in moist areas is that in a dry summer clay just bakes and dries out so you need that fine balance of plants that can tolerate both!

One tip is to look at what’s growing in your neighbours’ gardens and where you can see a thriving garden, make friends and ask them how they have successfully established their plants.

My mum lived in N London with a 115foot x 40 foot wide garden (ludicrous amount of land to tend), half of which had a slight slope, with heavy clay soil and her garden was fabulous.

She tackled water logging as follows:

1. Plant a row of fruit bushes about 15 feet from the foot of the garden. You could try blackcurrants, redcurrants, gooseberries, raspberries
2. behind your fruit hedge: two or three big compost heaps. All your food and non-weedy garden waste goes here, probably along with a hedgehog. You will create free soil of fine quality that you can use to dig into and dress your borders
3. get two or three water butts installed for when the garden is baking in the sun
4. along the edges of your borders dig a deep trench about 5 inches wide. This will encourage surface water to pool there while it slowly seeps away, instead of water logging your borders. In the spring, frogs would lay spawn in the puddles they say for so long! Be sure to move them to your wildlife pond before the spring sunshine dries them up. Oh, did I mention you need a wildlife pond?
5. Buy a heavy duty garden fork and spade and do all your digging in autumn and early spring. Don’t dig too deep as you’ll hit clay - if in some places the clay is really near the surface, remove the big lumps and put them in your garden refuse bin. Replace with pear free compost (you can purchase some until your compost heap is delivering the goods). Once even slightly dry weather arrives, you won’t get a fork in the ground. By this method you will be insanely fit too - my mum lived in perfect health with a resting heart rate under 70 until she dropped dead of other causes in her late 80s - she swore it was the decades of digging that kept her well.
6. Create a rockery. A bit unfashionable, but you can use some of your claggy soil to build a mound and then get some large rocks and inter plant with bulbs and alpines. By gardening upwards, you avoid the worst of the clay soil.
7. Finally I’d say, don’t just do a border along the end of the fence. In a big garden it will look boring. Sculpt your borders in waves, or section your garden with areas of planting that cut the garden into pieces. Plants in the middle of the garden in full sun most of the day will flourish - you can have all manner of flowers including roses, as well as fruit trees. My mum had success with blackberries, plums, damsons, apples, pears, shrubby quince, even grapes! You have space to experiment

Roses, Alchemilla and Hydrangeas love clay soil. So do potatoes, beans, peas, fruit trees and anything that would grow happily in large pots (as you can dig a hole and dump a bag of compost and sand in as though it's a pot).

You could also start up a compost bin to create some less claggy areas.

It depends entirely upon what you'd like to have - a Mediterranean garden would be more difficult and require a lot of sand/grit to be added, filled with ericaceous plants isn't going to work - but you could have a garden absolutely filled with scent, colour and bees, plus some very nice meals from a large, sunny space like that.

Ahh, I have the exact same sort of garden, at the moment it is like a swamp. When I first moved in I thought nothing would grow, so it’s been a process of trial and error. So for example plants like lavender that don’t like their roots wet have failed. However the good news is that there are things that work. Roses are fantastic and actually like clay, hydrangeas, escallonia, I have two happy pittosporum, hardy geraniums (Patricia is particularly good), astilbes, mahonia, astrantia, Thalictrum, fuschias, foxgloves, ferns. If you have acid soil that also helps as rhododendrons and camellia seem quite happy too. I’ve given up on trying to grow things I like that don’t suit the conditions and my garden actually looks pretty great in summer (I just can’t walk on it now!)

MinnieMowse great advice. Thank you so much.

This is so helpful, thank you!

My South facing heavy clay garden is full of rhododendron, azaleas, heathers, tulips, crocosmia, lillies, gladioli, all sorts of allium, buddleia, photinia, euonymus, pieris, clematis, jasmine and a miniature standard rose. We also have an ornamental cherry and weeping silver birch (had another cherry but it died last year as apparently that type only live for 40 years). Whenever I plant I make the planting hole much larger so that I can improve the soil bit by bit. It's hard work but working well! Also the beds are covered in a very thick layer of bark chips as this helps filter the water into the soil slower, keeps the soil damp (not wet) in the dryer months and keeps the weeds down. I refresh it every couple of years as it breaks down (feeding and improving the soil as it does). I know bugger all about gardening but I'm really pleased with how it's come together.

Remember, Loam = clay + humus (roughly). So you have the makings of a really fertile garden!

Do try to start a compost heap. Putting a 10-15cm layer of mulch on the soil will transform it over 3-5 years into crumbly black soil. See if you can source free low cost mulching materials, eg spent mushroom compost, brewing waste. Don’t take dead leaves, lawn mowings to the tip, use them instead.

Meanwhile, avoid plants which say they want a well-drained soil.

I too have standing water. The plants I’d add to the lists above are taller Lysimachia (yellow loosetrife), Lythrum (purple loosestrife), candelabra primroses, which famously grow along the streamside at the RHS garden at Harlow Carr (worth a visit if you’re ever in the area to see what can be done in a clayey frost hollow). And I have a swamp cypress.

Watching with interest. We bought a derelict property which was completely overgrown with brambles/ivy etc. Its cleared and we have some lawn, but need to design borders, trees, shrubs etc. Also heavy clay. Leucojum's did naturally grow in the borders, so I assumed spring bulbs would work.

Last year, I did planted- daffodils, tulips, alliums which did very well and are coming up again. When I dug their bed, I added some garden grit underneath and put the bulbs into bulb baskets. Mainly, because I wasn't sure how they'd grow and some alliums can become invasive. Rose love clay too.

We have heavy clay too, dries like concrete and then the water sits on top in the rain - horrible stuff IMO.
Anything that likes well drained soil probably isn't going to do as well. We've never managed to keep lavender for long. Rosemary grows brilliantly in summer then hates the winter wet. We don't have much luck with the big alliums either although I love them.
We find snowdrops, winter aconite, cyclamen, primroses, cowslips, daffs, pulmonaria, blue bells, thalictrum, marigold, foxgloves, crocosmia, roses, alchemillia mollis, scabiousa, knautia mecedonia, sisyrinchium striatum, ox eye daisies and Japanese anemones all grow well. Anything that grows in a woodland or a meadow seems to do well.

We also have clay but seem to get the neighbours surface water as we're slightly lower. We're hiring an auger and will put in several deep holes around the border fill with pea gravel then top with soil and plant around it.

I'm looking at Mount Aso willow a small thirsty tree that doesn't have a huge root system. Plus we're planting more trees this year in general. It's such a pain, a lovely garden in summer and winter just a waterlogged mess.

I have south facing clay. Mulch is your friend. Top dress any beds with homemade compost, leaf mould, coconut compost or anything organic in autumn. The worms will take it down into the soil, you don't need to dig it in. Anything remaining on the top will help retain moisture. You will need to water in dry summer, even though it probably looks like a series of ponds now.

Things currently in the ground in my garden include mahonia, erysimum, forsythia, raspberries, apples, greengage, limnanthes, spring bulbs, chrysanthemum, lilac and hollyhocks. I plan to create a hardy tropical area this year, so see how that goes.

Aren’t you just going to create little water filled holes? You’re basically creating a French drain with nowhere to drain to

@MereDintofPandiculation no we don't have compacted clay so holes will be 3ft deep and should drain. (She says)

@WildFlowerBees i can confirm Mount Aso thrives in clay.

@AmusedMaker, you’ve got lots of excellent advice on cottage style gardens- but if you want to take your garden in a different direction, a lot of tropical and tropical-looking plants also do very well in clay soil. Cordylines, many palm trees, bananas (musa basjoo, musa sikkimensis, ensete maurelii), fatsias, cannas, tetrapanax, colocasias, pseudopanax, trochodendron, persicaria and ferns are all happy in my clay soil garden. Many of these plants love water, so as long as you don’t let the soil dry during the odd dry spells, they’ll thrive.

I do add compost and bark chip mulch every year and feed regularly - big leave plants tend to be hungry feeders.

I find crocosmia, eucomis and salvias go well with tropical plants to add a spot of colour.

Also consider adding some tall grasses- not bamboo or other invasive types, but e.g. miscanthus (Indian summer has great feathery tufts) that look good in winter. Junca spiralis also does great in water. Ornamental grasses help fight climate change as they are a great carbon sink.

That's good to know @Koulibiak I was going to buy one yesterday. I definitely will now!

Koulibiak

thank you, really appreciate your advice.