"Blue Rug" is a common name for various juniper cultivars, particularly those that have a low, spreading growth habit and often exhibit a bluish or silvery-blue color in their foliage. These cultivars are popular for ground cover and landscaping due to their attractive appearance and hardiness. One well-known example is the "Blue Rug" juniper, which is often associated with Juniperus horizontalis.

Here are some key features of Juniperus horizontalis 'Blue Rug':

1. Growth Habit: 'Blue Rug' is a low-growing, spreading juniper that typically forms a dense mat close to the ground. It can spread over a wide area, making it an excellent ground cover.

2. Foliage: The foliage of 'Blue Rug' is often bluish or silvery-blue, giving it a distinctive and attractive appearance. The needle-like leaves are arranged in a scale-like pattern.

3. Size: It has a prostrate growth habit, reaching a height of about 6 to 12 inches and spreading several feet horizontally.

4. Hardiness: 'Blue Rug' is known for its hardiness and ability to tolerate a variety of soil conditions. It is also resistant to many pests and diseases.

5. Sun Exposure: These junipers typically prefer full sun but can tolerate partial shade.

6. Drought Tolerance: Once established, 'Blue Rug' juniper is drought-tolerant and requires minimal watering.

7. Landscaping Use: Due to its low, spreading nature and attractive color, 'Blue Rug' is often used as ground cover in gardens, landscapes, and slopes. It can also be used to provide erosion control.

When using 'Blue Rug' juniper or any other juniper cultivar in your landscape, consider its specific needs and characteristics, such as soil conditions and sun exposure. As with any plant, it's recommended to check with local nurseries or garden centers for advice tailored to your specific region and conditions.