I planted about 20 in early March, a mix of Leylandi (to fill a hole
in an existing Leylandii hedge) and Lawson to create a new hedge
because it's more native and managable.

I planted bare root stock 3 - 4 feet high, 2 feet apart, and have been
watering them almost daily.

I want the Lawsons to grow to about 7 feet high and the Leylandii to
grow to about 12 feet. What I want to avoid is them being spindly, the
Leylandii in particular I'd like to spread out but I still need them
to grow up to match existing trees.

My question is should I take the tops out now, I understand this will
encourage sideways growth but will they still grow up and if so how
fast ? Alternatively should I wait until they reach the required
height and then top them ?

Thanks,

David C