Herbaceous perennials, winter to spring

Roses can die if the area had recently had other roses in, but the fact your perennials have apparently died too suggests something bigger is wrong with the actual soil. The plants on your list are susceptible to different pests, so it's unlikely these could have been responsible for killing such a range through the winter. Heucheras can get their roots eaten, but normally there is still top growth, which just detaches and wilts.

How long have you been gardening in this soil? Has anything thrived? When you moved in, was anything growing there?

Try not to be disheartened. Once you establish what the problem is, you can progress from there.

 

This is very worrying! Most of those plants are tough as old boots when it comes to winter cold. They wouldn't like being sodden/waterlogged all winter but in a raised bed with adequate drainage that shouldn't have been a problem. A ew possibilities:
1. slugs eating the new growth before it's had a chance to get going,
2. planted as small plug-type plants. Most are better grown on somewhere a bit sheltered until they're filling decent-sized pots (maybe 1 litre or more) before planting out.
3. Mulching too close, touching or covering the plants, can lead to rotting off particularly if they're small, and can harbour slugs.

 

If nothing at all is coming up, you could try a test. Get a packet of something cheap, hardy and quick-germinating that has lots of seeds in the packet, maybe a hardy annual, green manure, mustard and cress, something like that, and sow it over the area plus a bit in a pot of decent new compost as a control. See what comes up and how well it grows. If it grows normally in the pot but not in the ground, that would suggest a problem with the soil.

 

I think that it would be a good idea to test the soil as well. It may not be a soil problem but this is very reminiscent of what happened to some members on our allotment site where they spread soil that unbeknownst to them, contained persistent herbicide. It would be a good thing to rule out but it some more detail on the size of plants and if anything is doing OK may help.

 

If your roses died, then your perennials died then it must be something to do with the soil. You could send a sample of your soil for testing at a lab but it can be expensive. But then it can be expensive when all your plants die.

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Chemical Analysis and Laboratory - Forest Research

 

I find it particularly worrying that Linaria purpurea didn't survive. While moderately short-lived as perennials go, it self-sows with abandon and grows in-situ holding its own amongst bigger plants. It keeps its basal leaves all winter (except that some older plants get woody and brown at the base and then die after flowering) and starts growing early. Bronze fennel similar but not so prolific and more prone to die after flowering (ie sometimes behaving more like a biennial).

 

Have you lifted any of the suspect plants to see if the roots are still viable? I'm thinking about vine weevil or similar.

 

Thanks everyone. Firstly, @Thevictorian, re the soil. I remember adding topsoil and bagged manure in 2023-2024 in big quantities when I planted the roses. In 2024, after the roses had died (one by one), I did add compost to plant the herbaceous perennials. (John Innes no 3 and multi purpose).
I am wondering if the bagged manure could have been contaminated with something. That is awful about the allotment and toxins. I used farmyard manure. It was something like "wonda-gro" (Don't want to mention the actual brand as I don't know if it was dodgy or not, but you can probably guess).
The plants all took a while to die. The ones still left are the ones I planted last. Saying that,some of the heleniums, rudbeckia and Japanese Anemone I planted later and they have not returned.

Edited to correct my mistake: I added John Innes no 3 as well, for the roses and topsoil also for the herbaceous perennials, along with the rest already mentioned.

 

Thankyou @ViewAhead, yes I thought it was rose replant disease to start with but as you mention, it seems something else.
i ran out of tags so can't say which plant is which exactly, but there is what looks like dark roots above and in the soil still that I think could be either Heuchera or Linaria Purpura. No green growth or anything that looks new and alive on this dark clump.

I extended this area, starting in about 2022 so I made it deeper in a sense. I extended the shallower garden into a bank/raised bed at one end. The plants that have come up are forecast the new, raised end. The bit in the middle is most bare and the bit that meets the old garden is probably ok, but I can't say for sure!

I will dig some soil and look for pests and growth.

 

Thankyou @JennyJB. The plants were mainly in 2 litre pots (a few 3 litres). I kept the plants under observation for a week or so (each one) before planting out. I inspected the roots before planting. All seemed well. Many were flowering or began to flower after planting. I had no sense of anything rotting from mulch, but by November, I wasn't checking ever day. Maybe it was that but I mulched around rather than on the plants.

I will try your seed sowing idea (with a control in a pot). I have mustard seeds I could try. I have mixed bird seeds as well.

Interesting about Linaria purpurea. I planted this in October when it was in flower. It continued flowering for quite a while I recall and then I realised (prob Dec-Jan) I could not see it anymore. The fennel has disappeared as have the four Stipa tenuissima - just tufts of old stems left.
Could it be herbicide drift from somewhere. I don't use any herbicide.

 

Thankyou @Busy-Lizzie, yes, it is expensive when plants die. I will have a look at your link. It would be very interesting to discover some laboratory testing results. I am going to stick to container planting from now on!

 

Thankyou @Sheal for that suggestion. I think I will select some areas to dig up, and inspect any remaining roots. I always thought wine weevils were more pot-oriented, but anything is possible.

 

Honey fungus can affect perennials as well as woody plants. Could this be a possibility perhaps? I’ve never come across it in my garden but looking at the RHS information it can be devastating.

 

I have honey fungus in my garden, and it has only attacked woody plants. I believe it has been known to attack some perennials, but the fungus seems not to decimate an entire area, but just affects the odd plant. And no perennials in my garden have been affected in the 5 years since the first rowan tree succumbed. Grasses are thought to be pretty well immune to the fungus, but yours have disappeared, which would make it even less likely that this is the cause of the problem.

I hope you find the answer - and a solution!

 

Horse manure was one thing that our allotment had problems with. It was the hay that had been treated with a persistent weed killer. There were also problems with greenwaste compost. I'm not saying that is the answer or most likely cause but it's an avenue to look at, I believe @infradig postep a link about it recently.