Garden Lighting Help sheet  No. 10: - Metal halide uplighting for larger trees

1. Uplighting of trees adds drama and vertical emphasis in a garden lighting scheme. Metal halide uplights have a narrow (spot) central beam to penetrate up through the branch structure and a peripheral beam to light the canopy which complements the central beam focused up the trunk & inner branches. Recessed uplights require a position above the water table with 300m of shingle drainage below the fitting; use spike mount uplights in ground subject to water-logging. Suggestions shown are subject to the tree having an open structure to allow the light beam to travel upwards; look up through the tree you propose to light – if you can see up through the branches, then light will be able to penetrate the canopy and structure as well. Lighting large trees is something of a black art: if in doubt, test the position and focus of uplights with a temporary wiring set-up before final installation
2. Where the outer canopy of a large tree is dense, uplight the trunk and centre of the branch structure with a spot beam uplight and position one or more metal halide floodlights to illuminate the outer canopy.
3. If the diameter of the canopy exceeds 10 metres, consider using 2 or more uplights for a fuller effect.
4. Use a symmetric beam floodlight where the light fitting is to stand back from the tree, perhaps hidden behind a landscape feature, wall or shrub. Floodlighting cannot generally be achieved with ground recessed units as the internal lamp adjustment is insufficient. T2120 70w floodlight will light many trees up to 15 metres well, unless the foliage colour is particularly dark. It is also an excellent uplight for wall washing applications and light large conifer hedge screens. Use T2160 150w floodlights for trees over 15m in height, where the floodlight is further than 10m from the outside of the canopy or where foliage is particularly dark in colour.
5. When the feasible position of the light is just outside the canopy or you want to “graze” up the foliage surface to emphasise texture, you need a floodlight that will light the bottom of the canopy but still “stretch” the light beam up towards the top. That is what an asymmetric beam floodlight or ground recessed uplight will do.
   

The T2130 70w asymmetric floodlight will light many trees up to 15 metres well, unless the foliage colour is particularly dark. Use the T2170 150w unit for trees over 15m in height or where foliage is particularly dark in colour. The T2020 35w asymmetric ground-recessed uplight will light many trees up to 10-12 metres well, unless the foliage colour is particularly dark. Use the T2030 70w recessed uplight with the adjustable lampholder set at an angle for trees over 15m in height or where foliage is particularly dark in colour.

The table below gives a choice of metal halide uplights using ceramic metal halide (CDM) lamps.

Product codes refer to spike mount uplights, floodlights  and recessed uplights marketed by Lighting for Gardens