A sedum roof is a living thing. And most living things in the UK adapt and change to the seasons. In this blog we’re looking at what you can expect from your sedum roof in winter.

The benefits of a sedum roof in winter

All winter long, your living sedum roof will be working hard for you.

Your green roof will be insulating your building against the cold.  Helping to keep the heat in and the cold out.

It will be absorbing rain water and snow melt so that your drainage systems are not overwhelmed.

Another benefit is that it will also be protecting your roof against the sudden temperature changes that reduce the lifespan of waterproofing materials.

In short, your sedum roof will be quietly making your life more comfortable and less costly.

woolly hat offering roof insulation for domestic home

A sedum roof acts like a layer of clothing for a building

What happens to sedum plants in winter?

If you have ever tested your green fingers, you’ll know that some plants do not like UK winters. Tomato plants, pelargoniums, courgettes and many others will perish at the first sign of frost.

Other plants effectively hibernate. The foliage dies back and until spring arrives you look at bare ground.

Some sedum species fall into the first category and some into the second. But most of the sedum species used to create Enviromat sedum matting will front out the winter weather. They keep their foliage, they stay very much alive and they laugh in the face of frost. In fact, Enviromat is frost hardy down to around -20 degrees.

What you may notice about your sedum roof though, is that it changes colour in winter. The foliage will go from a lush green to a reddy-brown colour. It’s definitely not unpleasant and it proves that the plants are in good condition. Poorly plants just look awful, but healthy sedums have a kind of defence mechanism that they activate when under stress. The same thing happens during very dry summers too.

sedum plants with winter foliage colour

The colour of sedum foliage as winter approaches. When the weather gets really cold, the red-brown colour will become more pronounced and the leaves themselves will appear smaller - like little red beads

You will also notice a change in the texture of the plant layer on your sedum green roof. During the plants’ growth season, leaves will be big and fat. They’re storing water for all they’re worth and it’s plain to see how this type of plant earned the title “succulent”. 

In winter time, a leaf that’s full of water risks being frozen solid. That would damage the cell walls. Plus there’s no need to store water during the wettest part of the year. So the plants keep much less water in their cells.

What you see when that happens, is not the succulent fleshy leaves of summer, but small, hard bead-like foliage. That’s normal and, from the plants’ point of view, it’s sensible.

Winter green roof maintenance

Trust me, a green roof is no place to be in the depths of winter. I’d hope that you’d managed to complete routine maintenance jobs before the cold weather set in. But just in case you didn’t, here are a couple of possible jobs – IF it’s safe for you to be on the roof.

  1. Keep those gutters and drainage outlets free of debris. I can’t stress enough how important this is.
  2. If you MUST walk on the roof, use laying boards to spread your weight and avoid damaging the plants. Damage to the cell structure at this time of year is hard for the plants to recover from.
  3. Remove debris from the roof. Things like fallen leaves and bits of rubbish will deprive the plants of sunlight and ultimately kill them.
  4. Check that vegetation mats are secure and haven’t been lifted by the wind. Make repairs as soon as possible if they’ve shifted. The last thing you want is to wake up one morning and find them on the ground.
  5. Order your green roof feed ready for the first spring application

Your wintertime sedum roof

In an ideal world, you won’t need to do anything to your living roof during the winter months. Instead, it will be working for you. Be kind though, don’t forget it’s up there and start thinking about your spring maintenance visit. If needs be, start looking for a suitable maintenance contractor or a landscaper who is able to help you. These firms get busy quickly in spring, so get booked in before everyone else does.

More about green roofing

Green roofing and winter insulation 

5 green roof myths busted

The history and culture surrounding living roofs 

Buy green roof feed online