Lemon Slice calibrachoa is pretty. Hybrids often do not produce seeds that will be true to the original Hybrid and Lemon Slice is a hybrid. In addition, calibrachoa don't produce a lot of seed and the seeds are mostly sterile. All of the calibrachoa that are available are propagated by vegetative cuttings, so only available as plants. The plant breeders have patents on most varieties, which prohibits propagation. Even the wholesale growers are not allowed to take cuttings and propagate.
Hope this helps...you will need to buy plants since no seeds are available