natural shading by plants

The trees I want around the wooden deck are plane trees. At first, it was said that they cost about 400-500 euros each with a trunk circumference of 14-16 cm and a height of 2.50 m. Now the landscape gardener said that they cost around 2,000 euros each! I could puke!

I have no tips regarding the pipes. We buy the plain stuff from the hardware store.

Regarding the plane trees... in an episode of the gardening show "Die Beetbrüder," plane trees were also used for green shading this summer, a price of 500€ each was mentioned. They were grown in advance with a roof shape and about 210 cm, I believe. Other tree nurseries also have beautiful trees!

On the internet, I also found plane trees costing from 200,- to 2,000,-. Those around 400,- would be completely sufficient for a start.

Pe-HD pipe. Fittings from Unidelta. Taps e.g. from Ideal.

The landscape gardener wants to lay the [Rollrasen] on Monday. Is that still possible in mid-November?

Sure, that doesn't bother him. I wouldn't put him down during a permanent frost, but better now than in May, when there will be months of heat and drought afterward. Better now, yes.