‘Jade Frost’ sea holly
‘Jade Frost’ sea holly (Eryngium planum) thrives in sun — in fact, the color of this perennial’s pale blue flowers intensifies in higher temps. The thistlelike blooms are cream when they first appear, creating bicolor appeal on just one plant. As these age, even the spiny narrow bracts turn blue.
The low-growing mound of blue-green foliage has a creamy white margin. When night temps are still cool, young leaves have pink-tinged margins. Deer- and rabbit-resistant, sea holly’s foliage looks great even before the flowers take off.
Blooms Pale blue from midsummer to late fall
Light Full sun
Soil Well-drained; tolerates dry, sandy
Pests None serious
Size 6 to 8 in. tall, 14 in. wide; 24 to 30 in. tall in flower
Cold-hardy USDA zones 5 to 8
Heat-tolerant AHS zones 8 to 1
Source Sooner Plant Farm