Two-tier waterfall with coloured light on a dark stone wall

A steel or aluminium unit with aligned perforations and an LED strip housed inside, built into the wall face and fed by a recirculating pump. Against a straight-lip weir it needs considerably less flow for the same width, so a smaller pump will do. The holes scale up in hard water: make sure it can be removed to be cleaned with vinegar once or twice a year.

A weatherproof controller wired between the driver and the fittings, with a physical remote and phone control. It's the part that decides the result: what matters isn't the preset colours but being able to drop the saturation and fix a tone. Choose one that saves scenes so you aren't hunting for the same blue every night, and check it matches your fittings, RGB or RGBW.

A 12 or 24 V power supply in a sealed box with cable glands — the part most often forgotten when planning a lit water feature. Add up every fitting's draw and leave at least twenty per cent headroom: a driver running at its limit heats up and is the first thing to fail. Site it somewhere accessible and not buried, because it's the first thing you'll need to check.

Medium-grade pine bark, spread five to seven centimetres deep. Below that it won't hold weeds back and you'll be topping it up every few months. It's the material that works best in a lit garden because it absorbs light instead of returning it, unlike pale gravel. Bear in mind it floats: where water runs in heavy rain, it ends up piled at one end.

A permeable geotextile laid under the bark or gravel and pinned down with pegs. Without it, within a season the bark mixes into the soil and the lot has to be lifted to renew it. Choose woven fabric over perforated plastic: plastic stops the ground breathing and waterlogs any sunken pots. Overlap the rolls by about ten centimetres, or weeds come straight up through the join.