It looks like a little patch of grass or maybe a really big patch if you ve let it go for a while.
Moss on the roof tiles.
Run the edge of the knife along the edge of the roof to remove the edge seal of moss on the shingle.
Moss is probably the easiest growth on your roof to identify.
Hose off and brush all moss loose from your roof shingles.
Use the round filed knife to cut moss under the shingles by inserting it under the edge of the shingle gently to avoid damaging the roof shingle.
If the above sounds like too much of a hassle which honestly it likely does then know that the most effective method is to prevent the problem of moss on your roof in the first place.
Keep your trees well trimmed to lessen the debris that falls onto your rooftop.
Moss growing under roof slate and tiles can push the slate out of position allowing rainwater to seep into the roof structure.
Leaves and other foliage that collect in your gutters.
Carefully place a ladder near the area of moss growth and don slip resistant shoes old clothes rubber gloves and eye.
When rain finds its way into the roofing structure that s when decay and rot sets in.
Ultimately moss growth on a roof can result in costly repairs and can also reduce the lifespan of your roof.
Moss can grow quite quickly and it will grow in between roof tiles filling in the voids and lifting up roof tiles and slates.