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Diseased? All plants in one area of garden dying -help!

Sorry long one -but really a bit puzzled about why this is happening and what I should do about it!

This is in my front garden, east facing, on a sideways slope and consists of 2 raised beds constructed of brick. Biggest (and problem one! ) starts at 4 brick high rising to 10 brick high (next to path) and is 4 m wide by 3 m long. Second bed starts on other side of path at 2 bricks high going to 8 brick high and is about 2m wide and 3.5 m long.

Lower bed gets less sun and has been more neglected - but everything is thriving - including lavender and two types of thyme, marjoram, mint, forget me nots, lillies, bluebells and snowdrops, parsley and sage etc ...

Upper bed still has a lot of space - over the years from both beds I have removed a couple of large shrubs and 3 big conifer type trees  - there is an empty area in centre (which does get neglected a bit - few weeds etc) and the plan has been to fill it in...with maybe a few paving stones in centre...but

Problem is everything has started dying in the big bed...towards the front wall...started with Rosemary - I had two - one that was larger and had been there for 7 years - suddenly the old leaves started getting brown under the fresh growth and it died (thought maybe the harsh winter had killed it off) - I removed it and replanted a new rosemary and that died too...

I have some arenaria (I think it is called - ground cover with white flowers in may/june) last few years they were lovely-  this year miserable with signs of dying from the centre , my two thyme plants (well established) are showing the same symptoms, my cat mint (cut back in the autumn) started with new leaves but has died too...I have a pink geranium (broad petaled -like the purple one but pink) -which is looking unhappy - I have had another couple of plants in there that have died but I think they were annuals and /or in general I like plants that are low maintenance so often try and if they don't survive move on ...but this is obviously a problem now...

So far everything else is all right (even though towards the back/house where it is more overgrown and tends to be damper -although I do have some shrubs/bay tree to take up the water) - I put some (homemade) compost on my strawberries last year (wild and culitvated - running along the edge of the path in this border) and they are fine...

I think it some kind of mildew fungus - Does that sound right? and am a bit stuck about what to do about it...

I tend not to water the garden at all (unless very very very dry) ...neighbour up slope has gravelled his garden with pots and does water the pots constantly in summer and puts weedkiller on the gravel - but I don't think this is weedkiller damage (it has sprayed on our garden before) and if it was water draining under I can't understand why it is suddenly a problem..(this started last year - I know this year has been very damp!)

Not sure if there is any drainage in walls (I can't see any -they were here when I moved in)...perhap conifers/shrubs were taking up so much water that it kept it dry (but overshadowed)? - a conifer stump was rotted enough to dig out 2 years ago - would this have caused the fungus (but I have one that I have left as a feature in lower garden - not causing any problems so far) - ...maybe it is short of nutrients? (but lower garden is fine...)

Thinking I should remove all the plants along the front and start again - If I do, do I need to leave it for a while -or just dig over  - or ? Should I put some homemade compost on there? Bought compost?  Something to encourage drainage (not sure what...) Really at a bit of a loss - last year (ignoring empty space! - it looked lovely - this year very sad...)



  • kate1123kate1123 Posts: 2,815

    Can I just clarify, are they diseased or are they just dying? Rosemary are notoriously fickle lots of people have lost them over the last 3 years. Is it a dry bed or is it waterlogged?

    I would take everything out and put some fresh compost in, then I would plant it up with some thugs that can cope with difficult conditions.

  • Alina WAlina W Posts: 1,445

    Have you tried digging up some of these plants when they are starting to fail to see what condition the roots are in? It does sound as if the bed may be waterlogged, in which case you need to think about taking out the odd half brick at the bottom to allow it to drain.

  • lusi83lusi83 Posts: 19

    When it was just my rosemary I wasn't overly comcerned - but now my thyme (which is flowering at the moment) has a big bare spot in the centre - showing the woody bits - it is the older parts of the plant which has lost leaves...which is what happened to the rosemary -it had nice green leaves at the top but lower down the leaves went black and fell off . I have an almost as big thyme in the other border which is fine ...

    And the arenaria in the centre of the plant is dead - brown withered stems - it only has a few weak looking flowers around the edges ...

    Area doesn't seem to be waterlogged...even with all the rain we have had ...just wondering if it is holding water lower down? (It is 3 ft high)  Would that cause mildew?   The slope runs down to a river/estuary -in really bad rain the path at the front looks like a river! Assuming same is happening with the gardens it could be pooling water behind the brick - we are more or less on the bed rock (I can see it under the floors of the house in places).

    I haven't dug down more than a spade or so deep - suspect that it wasn't filled completely with top soil...might be tough to get down to any depth...  



  • lusi83lusi83 Posts: 19

    Sorry hadn't seen Alina's post   - so would the roots look rotten?


  • Alina WAlina W Posts: 1,445

    They would look brown and be soft, rather than white and crisp. The lost leaves at the centres of the plants do suggest that they're dying from the roots; the mildew is really a sign of a weakened plant rather than the thing that's killing it.

  • lusi83lusi83 Posts: 19

    Thank you -

    I'll check it out (but probably not today -absolutely chucking it down again!)

    On closer inspection there are a couple of what I assume are drainage channels in the bottom of the wall - but they seem dry - I will have a poke about in them and see if they actually go straight through (it is double walled and think this was another job done by 'Mr. Bodge It' one of previous owners  - nothing would surprise me! )
    and I'll check the condition of the roots ...I'm assuming I have to get rid of them all anyway...but can leave the soil?

    And if it is a sign of a weakened plant - wondering if compost/feed might help too - 


  • Alina WAlina W Posts: 1,445

    You can certainly try feeding, but it does depend on the plant having enough roots to take up the food.

  • lusi83lusi83 Posts: 19

    Thank you  - I'm now thinking of nitrogen depletion and rotting wood might be a factor - I am still finding bits of root in the ground in this area from removing a big shrub and one of the conifers thinking feeding can't do any harm ...

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