Groenendael grooming is moderately time-consuming--and much of the work will consist of maintaining these dogs' thick, double-layered coats. The coats shed a fair amount for most of the year, and heavily during the late spring (and sometimes fall) shedding seasons. This means consistent brushing will be necessary to minimize the shedding, and to reduce the development of tangles in the heavier furnishings.
For most of the year, Groenendael brushing will be needed 2-3 times per week. First wet the coat with water mist from a spray bottle, then use a pin brush to go through the coat section by section, moving in the direction of hair growth. If you run across a tangle, first try separating it with your fingers, then if needed continue working through it with the end teeth of a greyhound comb. (During shedding season, daily brushing is best; some owners also use de-shedding tools during these periods to help with dead hair collection.)
Belgian Shepherd bathing is needed every 2-3 months--unless, of course, the dog gets especially dirty or stinky and an "emergency bath" is in order. When bathing a Groenendael, be sure to use shampoo (and conditioner) made for dogs, as the human kind has a different pH and can irritate the dog's skin. Also take the time to rinse the shampoo completely from the coat; leftover soap residue will cause further skin irritation.
While Groenendael haircuts are possible, they're not recommended. These dogs' double coats provide natural insulation and regulate body temperature--so in a nutshell, a shaved Belgian Shepherd will suffer quite a bit.
Though owners can learn to perform all aspects of Belgian Shepherd grooming themselves, it's a good idea to take the dog to a professional groomer at least once. The groomer can give the dog a nice makeover, and provide tips on how to groom a Groenendael at home.