Frequently asked green roof questions


1. What is the cost of Bauder Maintenance and how do I go about getting a quote?

Please contact Bauder by email: or call 01473 257671An idea of the approximate area, pitch and type of roof would help us in producing more accurate quotation.

2. Do I need to maintain my green roof/How do I look after my green roof?

Yes. We recommend maintenance should be carried out at least once a year for sedum roofs/twice for wildflower roofs. Maintenance promotes healthy growth, biodiversity and reduces the chance of weeds establishing. There are a few simple things that will help your green roof. Weed the roof (once or twice a year). Sedum roofs should be fed every spring (using Bauder Organic Slow Release Fertiliser). Avoid walking on the vegetation. Water the roof regularly during hot dry weather.

3. What happens if I do nothing to my green roof

Generally the roof is likely to deteriorate over time. Weed species are more likely to take hold and can choke out other vegetation. The amount of flowers are likely to reduce year on year. Drought conditions are likely to kill off some species reducing the diversity of the roof flora. Some weeds (tree saplings, buddleia & bamboo) can cause structural damage to the waterproofing of the roof if not removed.

4. Do I need to water my green roof after installation/in the long term?

Initially to bed in the green roof and allow for healthy establishment surface watering is required regularly for the first 6-10 weeks. This is particularly crucial if installation coincides with the spring / summer months. Treat the roof as you would a freshly laid lawn. Evening or early morning watering every day, watering the roof to saturation point (wet to the touch).
Following this establishment period irrigation becomes project specific and something that should be discussed at the initial stages of the green roof conception (see Bauder’s Watering Guide on the Bauder website).
ALL green roofs will benefit from watering in period of hot dry weather. Sedums are much more drought tolerant than British native wildflowers but Bauder always recommend there should be a way of watering a green roof in dry conditions (see Bauder’s Watering Guide).

5. My sedum roof looks dead / red, what is wrong?

When sedum is stressed in very cold or dry weather it can give a ‘reddish’ appearance, this is quite normal and it should recover (in the summer the red colour is an indicator that the roof should be watered). In some situations it may signify that the roof is in need of fertiliser. Also remember that some sedums are deciduous (meaning they will lose their leaf in the winter), these sedums should recover fully in the spring.

6. My sedum/wildflower roof has lots of grass/weeds - what is wrong and what can I do?

Sedum Roofs: Weeds can and do occur from time to time on green roofs. Normally the sedum is a dense mat of plants and there is only limited room for grass / weed to establish.  Sedum is drought tolerant and should over a number of years remain the dominant plant species, however in very wet summers and warm winters grass can establish. Regular removal of weeds by hand during annual or biannual visits should prevent weeds becoming too established.
Wildflower Roofs: Weeds are just plants growing in the wrong location, Wildflower mixes tend to have small amounts of grass and weed like species in their growing mix. These are only a problem if they start to dominate the other vegetation or are unsightly. Regular removal of weeds by hand during biannual visits should prevent weeds becoming too well established.

7. My sedum/wildflower roof is bare, what is wrong?

Sedum like all plants need feed and water if the plants have struggled for a prolonged period of time the plants shrink back and their leaf size is reduced, eventually this can cause bare areas. Sedums are not like grasses and do not take kindly to trafficking. 
Wildflowers are more susceptible to hot dry conditions and flower, go to seed and die back very quickly in hot dry summers, watering will prolong the flowering season for most species. Wildflowers are not like grasses and will be damaged by trafficking.

8. Do I need to feed my sedum/wildflower roof?

Sedum Roofs: Yes we recommend a feed once a year, which would be part of the Bauder Maintenance Contract. 
Wildflower/Biodiverse Roofs: No almost certainly not, Native wildflower species typically grow best in low nutrient substrate. Feeding the substrate normally means that the plants are out competed by weed and grass species. We recommend the roof is assessed prior to any feed, which would be part of the Bauder Maintenance Contract. 

9. The pebble stone edge is full of sedum, is that ok?

As part of the maintenance visit, gutters and drainage channels will be checked, and if required cleared or sprayed, to assure good drainage is occurring on the roof. This is important to the health of a green roof and important for fire safety.