1858. Gothic church with 6-bay nave and square 2-stage tower with octagonal spire. Small blocks of roughly squared and snecked rubble with sandstone ashlar dressings, some stugged. Raised ashlar base course and eaves course. Sawtooth-coped, 2- and 3-stage buttresses; hoodmoulds with label stops. Trefoil- and multifoil-headed lights, some set into pointed-arch frames; traceried NE window. Chamfered reveals, stone mullions and raked cills. Boarded timber doors with decorative ironwork hinges.
NE (PRINCIPAL) ELEVATION: stone-finialled gabled elevation. Centre bay with steps up to deeply-moulded doorway with flanking engaged colonettes and 2-leaf doors under elaborate stepped hoodmould with trefoil moulding at each step and as blind arcade at apex, and flanking buttresses with moulded detail at 1st stage; broad, 3-part window above with wide 2-light traceried centre and glazed trefoil in gablehead. Flanking bays each with 2-light window in pointed-arch frame. Tower (see below) to outer right.
TOWER: engaged 1st stage with moulded doorway to NE giving way to stepped and battered dividing course adjoining 3-stage angle buttresses. 2nd stage with narrow light at centre NE and narrow bipartite to NW giving way to corbelled, rectangular-plan, 2-part, louvered opening piercing mutuled cornice and rising into pedimented clock face at each elevation. Set-back, finialled octagonal spire with tiny fleche to alternate faces close to apex.
SE ELEVATION: 5 regularly-disposed bays, each with tall 2-light window and dividing buttresses; voussoired, roll-moulded, pointed-arch doorway with flanking buttresses forming small porch. Glazed rooflight to right and 2 diminutive roof ventilators close to ridge.
SW (REAR) ELEVATION: gabled elevation with tall traceried lancet to right, pointed-arch opening high up at centre and gablehead stack. Low piend-roofed projection (vestry) with door and 2 windows adjoining Church Hall (see below) beyond. Steps down to basement boiler room.
Largely diamond-pattern leaded glazing with some coloured glass and margin glazing to traceried windows; small pane glazing patterns in timber sash and case windows. Grey slates with fishscale bands to spire. Ashlar-coped skews with moulded skewputts. Cast-iron downpipes with decorative rainwater hoppers.
INTERIOR: raked gallery with simply carved panelled front on cast-iron columns to E; simple fixed timber pew benches, some box pews at gallery, and alternate pews with cast-iron umbrella stands; broad-span, timber-lined, hammerbeam roof. Vestibule with carved stone font, decoratively-panelled doors and cantilevered winding staircase with decorative cast-iron balusters; marble, timber and bronze mural monuments including WWI memorials (see Notes). Aisle doors lead to body of church with dominant carved organ housing to W incorporating lectern at centre and flanked by pointed-arch doors with traceried windows beyond; carved pulpit and font. Tower clock dated 1869 by Blairgowrie maker.
CHURCH HALL: rectangular-plan, slated, rubble hall with decorative bargeboarding, decorative ironwork finials and boarded timber doors.
SW ELEVATION: centre bay with raised-centre tripartite window in over-arched frame; timber doors to flanking pitch-roofed porches with raised ashlar base course.
NE ELEVATION: square-headed window to centre, low building (vestry) projecting at right and blocked door at left.
SE ELEVATION: door and 3 small windows grouped toward outer right.
INTERIOR: boarded dadoes; boarded doors with decorative ironwork door furniture to vestry, and panelled doors; timber fire surrounds. Large 4-part folding door and some open-timbered roof space with metalwork braces.
Ecclesiastical building no longer in use as such. Opened 2nd December, 1858 by Reverend Dr Guthrie of Edinburgh, as the Free South Church. Macdonald describes it as a "chaste, comparatively plain Gothic nave about 85' long by 44' high", he continues "the church as a whole, in its external aspect and its internal arrangements, is such as secures a high degree of comfort for the congregation". The building became St Mary's South Church when the nearby St Mary's Parish Church was demolished during the 1970s, at which time some mural monuments were added to the vestibule. St Mary's South closed on 29th January, 2002 at which time the congregation united with St Andrews Church to form Blairgowrie Parish Church.