For outdoor lighting you can't go past hue. These work really well and are really bright.
They do require a fair amount of effort to install. Plan in advance where they will go. While the cables are waterproof (and can be placed underground or in dirt/wet places) the connectors are IP67 not IP68 so while they can be subjected to rain they cannot be submerged in water so the connectors need to be above ground.
The result will be a lot of light and color making your garden (potentially) a lot more inviting and beautiful. Note that this is for the extension unit you still need a base unit to supply power.
Philips Hue White & Color Ambiance Outdoor Smart Spot light extension, power supply and mounting kit, Works with Alexa, Apple Home Kit and Google Assistant