When sedum green roofs first became fashionable in the UK, one of their USP's (unique selling points) was that they are "low maintenance". Unfortunately, architects, developers, buildings' managers and maintenance folk interpreted "low maintenance" as "no maintenance"
Oh dear.
That was very wrong indeed.
- A sedum green roof IS drought tolerant --- so it rarely needs irrigation.
- It is frost hardy----so doesn't need replacing after a bad winter.
- It is low growing----so it doesn't need mowing, pruning, clipping or any of the other gardening jobs associated with herbacious perennials.
- It is quite thrifty when it comes to nutrients----so no need for frequent feeding as you would roses or tomatoes.
However, what is often overlooked with such an easy-going plant palette is that
- A sedum roof IS a living thing. Which means that it DOES need an adequate supply of water and of the right nutrients.
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| Plants like this Sedum spurium need a booster feed in spring when they're growing on a roof |
A living green roof is just like a huge container
garden. The plants growing in it have a finite amount
of growing medium to get their roots into. That means that there is a limited supply of nutrients for them to enjoy.
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| A green roof is equivalent to a large, shallow plant pot. It needs similar care to your houseplants, raised beds and planted containers----but on an industrial (and more manageable) scale |
At ground level, microscopic organisms in the soil pull nitrogen from the air and recycle dead plants and bugs to make a certain amount of plant food. BUT, on a green roof, the substrate (growing medium) has been engineered to suit the needs of the building (light weight, free draining, with particles that are too big to wash off). Green roof substrate is super, but the structure of it doesn't support soil microbes very well.
In addition, the harsh conditions on a roof put extra strain
on the plants’ metabolism so, just like us when we’re working hard, green roof
plants need the right food (and plenty of it!) to keep them in good health.
So, even self-sufficient plants like sedums need a little extra help if they are to thrive on a green roof and provide all the benefits you want them to. ie insulation, cooling, wildlife habitat, good looks, showing off your "eco" credentials.
Here's what you need to keep your green roof in tip-top condition:
If you're still at the design stage.....choose your plants carefully and put plenty of thought into how your green roof will be maintained in the years to come.
If you already have a living green roof you will need some of this
Enviromat
Natural Green Roof Feed has been specially developed to help you and your
clients to get the best out of their green roofs.
It comes in a bucket – so it’s easy to carry up on to a roof.
The granular feed is easy to store and
easy to apply.
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| YUK! a neglected sedum roof. The hungry plants are too weak to hold the growing medium in place with their roots. This roof looks ugly and its thermal performance is probably very poor. It's not much use to wildlife either. |
The formulation for this highly specialised feed is 7.9% Nitrogen, 2.97% Phosphorus, 2.47%
Potassium and a whole host of essential trace elements that are needed to keep plants healthy in stressful conditions. Enviromat Natural Green Roof Feed is a slow
release feed, so on a healthy living roof, one feed a year is enough.
Order
your Green Roof Feed online or phone Q Lawns for a quote: 01842 828266
