"The" heath doesn't really exist. Although the Lüneburg Heath has the largest contiguous heath areas in Europe, these are more of individual, large areas that are spread over the entire width of the Lüneburg Heath. An exception is the large Lüneburg Heath nature reserve with its huge heath areas.
Due to the different locations, sometimes on a slope, sometimes on the south side, the heath areas bloom at different times, and the beginning is almost never the same. This ensures that you can find blooming heather as early as the end of July and the last blossoms can sometimes still be seen in October.
The heath areas are all named, e.g. Kronsbergheide. They are all part of the Lüneburg Heath and thus make orientation easier.
The heather plant that is primarily found in the Lüneburg Heath and characterizes its landscape is the common heather - "Calluna vulgaris". It is also often referred to as heather. The bell heather (Erica tetralix) usually flowers a short time before the common heather and prefers swampy areas such as raised bogs.
The rule of thumb for the heather blossom is 08.08. to 09.09., but of course that always depends on the overall weather conditions. In the last two years, the heather blossoms have already started in the last days of July. The large sea of flowers arises from about the 3rd-4th week, so around the middle/end of August. The heather needs rain and sun at certain times to sprout well. The first forecasts about the heather blossom can be made in June.