The reel looks light in its box. On the wall it carries hose, water and the repeated tug of someone watering the farthest planter. Treat it as a loaded fixture, not a slightly larger set of house numbers.
Choose the reel before choosing the wall anchors
Obtain the exact installation manual, bracket dimensions and supported wall types. Check the full operating sweep and the path of the hose around corners. A neat location beside the tap is not useful if the bracket strikes the door or the hose rubs an edge every time it is pulled.
GARDENA: approved wall hose-box mounting limits its wall box to the approved wall-bracket arrangement. That is a good reason to avoid improvised upside-down or overhead mountings. Other reels need their own approved installation details.
Suitable known wall
Use the reel instructions and a connection designed for that substrate.
Siding over uncertain backing
Have the concealed support and weather detail assessed first.
No practical wall connection
Choose a purpose-designed ground-mounted or portable reel.
A mounting block does not create structural backing
A block can bridge a siding profile and provide a flat face. It does not tell you whether the material behind it will carry repeated pulling. Ask the installer to identify the supporting substrate, suitable anchor arrangement and protection of the wall opening.
Brick veneer deserves particular care: what looks like a thick masonry house from outside may be an outer skin. Do not select anchor size or drill depth from a generic online example. Cracked, loose or deteriorating masonry needs assessment before adding a loaded fixture.
Keep the hose connection serviceable
Make sure the tap can still be operated and the hose disconnected without removing the reel. Leave the manufacturer's access for removing or servicing the reel. Photograph the bracket before the unit covers it and retain the instructions.
If the bracket rocks, the wall cracks or the siding is being crushed, stop using it until the connection is checked. Adding another random screw is not a load assessment. Compare the lighter-duty house-number mounting questions and keep any brick drainage openings unobstructed.

