When to mulch flowerbeds?

Ann85 · October 2020

Here in Kent I leave Dahlias, tender Salvias etc in the beds (unlike Monty in his garden I saw last night) because it is usually mild for most of the winter - obviously though it can be freezing. Most things survive this way and I have no cold frame...I’ve bought already lots of organic soil improver as the clay soil is like iron in some places in summer time. I want it to improve the soil texture and protect plants. I usually layer it on quite thickly around this time of year but when exactly is best? Now when it’s warm so worms can work it in or later in winter mainly to protect tender plants finished then? Thanks for any tips and ideas!

Fairygirl · October 2020

Whenever you want is the short answer.

Soil can be conditioned at any time of year, by adding organic matter, but in dry weather, and in dry areas, mulching heavily can prevent moisture getting in, so it's usually better to do it anytime from autumn through to spring, to help preserve moisture.
It also depends on the plants - you don't want to heavily cover anything that may be affected by wet sitting on it, so just be guided by whatever plants you have, keeping the main crown of plants clear.

chicky · October 2020

I always mulch my flower beds in spring - but thats because I don’t cut much back in autumn, so its difficult to get on the beds to see what I’m doing. I also avoid putting any on the crown of plants, for the reasons Fairygirl gives. So I wait til things are just starting to emerge - normally in March.

I know plenty of others who do all their mulching in autumn though- so I think you can take your pick.

Dirty Harry · October 2020

Fairygirl said:
It also depends on the plants - you don't want to heavily cover anything that may be affected by wet sitting on it, so just be guided by whatever plants you have, keeping the main crown of plants clear.

For helping to protect borderline hardy plants i.e. Salvias, would you also leave the crown clear?

Fairygirl · October 2020

I don't know - they aren't terribly hardy here generally, so I only grow one, and it's potted and tucked away against the house over winter.

A frame with fleece, which would allow air flow, might be better. You could then mulch around it to benefit the soil, but keep the plant protected. Many people take cuttings of salvias though, to give them back up

Ann85 · October 2020

Yes I took cuttings of Love and Wishes last year and the original survived so now I have 4...hoping it wasn’t a fluke that the one survived the winter! I was warned at Kent Flower Show when I bought it that it would not survive, hence the cuttings.

I can’t remember if the original died back as such but I don’t think it did in the way Dahlias do (and when they do I always cut all the stems off completely as they are hollow and I feel like that would let cold icy rain in) so I think I would’ve mulched just all around the Love and Wishes and cut it back in Spring

parrotfeather* · October 2020

I think a lot depends on what you mulch with and the type of soil you have. I lost Love and Wishes last winter but generally manage to keep the more robust tender Salvias such as Amistad through the cold weather here in the East Midlands by covering the crowns with a deep, dryish mulch such as bark chippings or composted woodchip and have success doing the same with Dahlias once they have been cut down. If using compost or manure I would certainly not cover the crown as I think it would rot. We also have light, sandy soil which is free-draining and on a clay soil things might be very different.

When to mulch flowerbeds?

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