how to filter data by month instead of date in laravel?

I am new to laravel and I could filter data by date but I don't know how to filter the same by month. Below is the controller function and views:

public function photo_gallery_show(Request $request) {

    $gallery_data = PhotoGallery::when($request->date != null, function ($q) use ($request) {

                    return $q->whereDate('event_date', $request->date);

                    })
                    ->paginate(10)
                    ->sortByDesc('event_date');

Select Month: Filter

    return view('front.photo_gallery', compact('gallery_data'));
}