Just done a custom integration. Using a cheap valve controller from Automatic 4-zone Lcd Display Watering Timer Irrigation System Garden Water Timer Controller With 2 Solenoid Valves - Garden Water Timers - AliExpress , wedged in a ESP8266, a step-up converter and a 3-to-8 decoder I can now control the valves from HA. Feeding it from 3.3V.
For the time being I still use a link-tap as main solenoid, the DIY unit is to split the one main into 4 distinct channels so I have enough water pressure on each one.
What currently works : have full control over the valves from HA using MQTT commands like cmnd/irrigation4_/VCLOSE 4.
What does not work yet: although my unit publishes the valve status tele/irrigation4_/SENSOR = {"Valves":{"v1":"1.00","v2":"0.00","v3":"0.00","v4":"1.00"}} I have yet to figure out how I get HA to recognize it.