Alpine Sea Holly features bold steel blue ball-shaped flowers with silvery blue bracts at the ends of the stems from early to mid summer. The flowers are excellent for cutting. Its attractive spiny lobed leaves emerge steel blue in spring, turning silvery blue in color throughout the season. The navy blue stems are very colorful and add to the overall interest of the plant.
Alpine Sea Holly is an herbaceous perennial with a mounded form. Its relatively fine texture sets it apart from other garden plants with less refined foliage.
Alpine Sea Holly will grow to be about 32 inches tall at maturity, with a spread of 18 inches. When grown in masses or used as a bedding plant, individual plants should be spaced approximately 15 inches apart. It grows at a fast rate, and under ideal conditions can be expected to live for approximately 3 years. As an herbaceous perennial, this plant will usually die back to the crown each winter, and will regrow from the base each spring. Be careful not to disturb the crown in late winter when it may not be readily seen!
This plant should only be grown in full sunlight. It prefers dry to average moisture levels with very well-drained soil, and will often die in standing water. It is considered to be drought-tolerant, and thus makes an ideal choice for a low-water garden or xeriscape application. It is particular about its soil conditions, with a strong preference for poor, alkaline soils, and is able to handle environmental salt. It is highly tolerant of urban pollution and will even thrive in inner city environments. This species is not originally from North America.
Alpine Sea Holly is a fine choice for the garden, but it is also a good selection for planting in outdoor pots and containers. Because of its height, it is often used as a 'thriller' in the 'spiller-thriller-filler' container combination; plant it near the center of the pot, surrounded by smaller plants and those that spill over the edges. It is even sizeable enough that it can be grown alone in a suitable container. Note that when growing plants in outdoor containers and baskets, they may require more frequent waterings than they would in the yard or garden.