Easily mis-identified as : Ice-Plant (aka Butterfly Stonecrop)

Hybridizes with : Butterfly Stonecrop (aka Ice-Plant) [Sedum spectabile] to produce Sedum 'Herbstfreude' aka Autumn Stonecrop/Autumn Joy which differs from Butterfly Stonecrop which has leaves in opposition in that at least some of the leaves are a alternate and is sterile and of garden origin, but escapees. There are two sub-species:

• Orpine (Sedum telephium ssp. fabaria) is much more common in the UK and with leaves usually sessile (un-stalked) and tapering to a cuneate (concave) base.
• Orpine (Sedum telephium ssp. telephium) has leaves which taper to a truncate (flat) base

Some similarities to : Roseroot another sedum with similar leaves but with larger and yellow not red flowers.

Slight resemblance to : Caucasian Stonecrop (Sedum spurium) in that it also has red flowers of similar size.

No relation to : Ground-pine (Ajuga chamaepitys) [a plant with similar name but in a different family].

You are much more likely to find this growing in or near a garden than growing in the wild, but it does sometimes, usually as escapes.