We often get asked: “Which is better for my green roof? Sedum? or Wildflower?”, and our response is always the same: “Well, it depends”.
You see, both types of green roof options are great, and they each have their own pros and cons. But which one is right for you?
Many factors should be considered when installing a green roof system, and these factors will help you determine which is the right option for your green roof. Will it be Sedum or Wildflower? Or even a mix of both?
Read on as we explore these factors and guide you towards the best suited option for your roof.
Green roof maintenance
When researching your green roof options, maintenance should be one of your top considerations. The shallower, extensive varieties of green roofs (usually Sedum-based) are typically designed to have simple, or no maintenance requirements at all. But this is not to say all can just be left alone.
Extensive green roofs may require watering on a regular basis, as well as the removal of undesirable plants such as weeds. It may also be necessary to check the drainage system is clear of debris, usually at least twice per year.
For green roofs with deeper substrates (typically intensive green roofs) further maintenance is needed. On top of regular irrigation, you may need someone or a team to undertake regular gardening work. This will involve mowing, pruning, weeding, replacing plants, etc. The substrate layer may also need maintaining as well. The intensity of the maintenance is dependent on the planting used.
At Viritopia, our green roof GrufeKits (these are extensive green roofs!) are available as Sedum, Sedum and Wildflower, or solely Wildflower (aka Brown Wildflower) choices.
Sedum, our most popular option, is an evergreen variety which arrives fully established with the tile needed for installation. It requires no mowing, regular watering, or maintenance at all. So, if zero maintenance appeal to you, Sedum is already looking like a strong favourite.
While our two wildflower options do offer a burst of colour when blossomed through the Spring and Summer, usual maintenance work is needed to keep them at their best. However this is not heavy maintenance, involving a strim of the wildflowers at the end of the Summer (this is optional), and removing any weeds.
Appearance of plant
Of course, when exploring your green roof options, you want to ensure the final product looks good on the eye. Especially if it’s visible from nearby windows.
Sedum is a hard wearing and drought tolerant plant which offers a pleasant colour all year round. It is generally considered as an aesthetically pleasing plant, but as is Wildflower.
So, how do they differ? Wildflower roofs offer a more varied mix of plant species for a wider range of colour. Wildflower roofs also allows windblown local seeds to grow, giving real biodiverse value. On the other hand, wildflower roofs usually consist of an intensive substrate seeded with a variety of wildflowers and meadow grasses. This means that when the wildflowers are not in flower, the roof is simple a ‘brown roof’, as only the soil is seen. Log piles, bird baths, sand dunes and local aggregate can be added, but it is worth bearing in mind that whilst a brown wildflower roof is also known as a ‘biodiverse roof’ for a reason, it is not usually the most aesthetically pleasing option.
Weight considerations
A factor that you may have passed your mind, the weight of the plants and substrate needed for them to thrive is very important. Put simply, if your roof isn’t structurally sound enough to support the weight, you could run into some serious problems.
Wildflowers require more nutrients than Sedum for growth, meaning the substrate will be deeper and therefore heavier. So, before settling on your green roof option, the weight limit for your roof must be considered.
To put things into perspective, our Sedum GrufeKit weighs 65kg per m2 (consisting of 8-12 Sedum varieties). While our Wildflower option weighs in at 75kg (consisting of 20-30 Wildflower varieties).
Your green roof choice: Sedum, Wildflower, or both?
With all that covered, you now hopefully have a better idea of which is the best green roof for you.
Do you prefer the idea a zero-maintenance option with the likes of Sedum? Or will a vast variety of colours and species with Wildflower outweigh the levels of maintenance needed?
But what if we told you there’s an option for both? Our Sedum & Wildflower green roof option provides a biodiverse roof consisting of Wildflowers on a base of evergreen Sedum.
For more information on our green roof offering and the options available, take a look at our GrufeKit Product Guide. Or, if you have any questions and would prefer to speak to us, contact our friendly team today – we’d love to help inspire your green roof choice for a naturally enhance structure.
