Bare root hedge clay soil fertiliser suggestions

IHateWeeding

I'm a novice gardener.

I have just planted 130 bare root hornbeam plants.

We have quite claylike soil, what's the next step I haven't trimmed to height (perhaps this is a mistake?) 

Am assuming water really well twice per week? 

What fertilizer would you use and how often in the first year?

 

Loxley

I would trim the tops lightly. I don't think it's critical to do so but it may help induce growth from lower down making them bushier. The watering regime sounds good.

Re fertiliser, if anything at all, I would use bonemeal in the planting trench during planting. You could work it into the soil around the new plants as you've already planted them. I view it as optional though.

I wouldn't give any further fertiliser in the first year (tbh I probably wouldn't in subsequent years either).