Despite being one of the most modern countries in Europe, Germany still holds onto many of its traditions. This includes gift giving, and it's common courtesy for a visitor to a German home to bring a small gift as a token of appreciation. This sets the tone for the evening and creates goodwill between you and your host for future meetings.
A box of chocolates makes a popular gift regardless of the language spoken. In social situations in Germany, a box of chocolates represents an appropriate housewarming gift. A foil-lined box full of an assortment of chocolates that you've wrapped in a crisp, metallic paper is an appropriate gift for a first-time visit to someone's home. Be aware that German traditions usually dictate that your host will open the gift upon your arrival. Ensure that the package looks nice, because chances are more than just your host will see it.
Flowers represent a common gift in Germany, and culturally speaking, people sending flowers to their German hosts often send the flowers the day before the event. Send an uneven number of flowers, but avoid sending 13 of them. Choose flowers like yellow or tea roses. If you're not completely sure, ask the flower seller. Explain the event you'll be attending; your polite gesture will likely be appreciated by both your host and the person selling the flowers.
Things to Avoid
Although items like flowers are common housewarming gifts to bring your German hosts, there are some gifts you should avoid because of the connotations of those gifts. While it's OK to bring roses, avoid bringing red ones, because they symbolise romantic love. Carnations represent mourning, and along the same vein, lilies and chrysanthemums are common funeral flowers. Also, if it's your first visit, avoid giving any gift that would be deemed too personal. You can also bring along a bottle of wine, provided that it's an imported wine; German wine as a gift would be an insult, because it gives the impression that you don't trust your host to select a good wine. On the whole, Germans --- especially older Germans --- tend to be formal. You should follow suit until you are invited to be more casual in your dealings with them.
Although you should avoid personal gifts like jewellery, other gifts can be a bit more personal to you without crossing the line. For example, if you know that your host family speaks English, think about bringing along a book that's produced locally about your city -- the kind that you find in the local section of your bookstore that are filled with beautiful pictures and interesting titbits about your city or state offer your German hosts a glimpse into your life. This gift works well if you've made the acquaintance of your hosts on previous occasions.