An alpine garden specializes in the collection and cultivation of plants that grow naturally at high altitudes. They are patterned after what one might find near or above the timberline in the mountains where hardy, adaptable plants grow in nutrient poor soil and scree among granite and basalt boulders. Compact, small-leafed alpine plants are able to survive cold, snow laden winters. The definition restricts or limits the plants that should be displayed in this type of garden. A rock garden can be comprised of alpine plants but will also include plants that will thrive in that particular setting which can vary based on the local climate and soil conditions.
Partly because of climate, which in many parts of North America precludes or makes extremely difficult the cultivation of many true alpines, and partly because of the availability of numerous charming small plants that are not alpines, most rock gardens do not limit their plantings to inhabitants of high mountains, but include other neat and choice kinds that look as if they properly belong.