Summer border combination
‘Millenium’ allium has an upright habit that makes it a cinch to tuck in between other summer-blooming plants and creates an interesting contrast to the mounding cushion spurge and snow-in-summer growing nearby in this garden plan. Its ball-shaped blooms stand out among the spiky salvia and domes of euphorbia. And if deer have been browsing your garden, this is one border they'll give a pass — these perennials rarely get nibbled.
Growing conditions for this drought-tolerant border
Give this drought-tolerant group full sun for the most flowers and best foliage color and well-drained soil to avoid rot. There's no real need to feed this group of plants that thrives in lean soil. Mulch every year or two with compost and it will provide plenty of nutrients to keep these plants healthy.
Plant care tips
'Millenium' allium doesn't need deadheading. Once the colorful midsummer flowers fade, the round seedheads provide an interesting accent for the border until late fall. This cultivar doesn't produce many seeds so reseeding isn't a problem.
Artemisia is mostly grown for its ferny silver foliage but small yellow flowers sometimes show up in late summer. They aren't that noticeable so there's no need for deadheading.
Cushion spurge and snow-in-summer do need to have fading flowers removed because they reseed prolifically (but aren't invasive). Instead of cutting individual flowers, make short work of this chore by using hedge shears to remove all the spent stems at once. Cut the outer stems a bit lower than the center ones to maintain a mounded shape.
'May Night' salvia blooms open from the bottom up. So once most of a flower spike has finished, cut it back to a pair of leaves so the side stems can take off. As those mature, sometimes the plant will splay open. If that happens, go ahead and cut all the stems back to the crown and new growth will fill in in a few weeks. While salvia does tolerate dry growing conditions, providing supplemental water during extra dry periods will ensure a stronger rebloom after the initial flush.
Garden plan plant list
A) Salvia Salvia x sylvestris ‘May Night’
Type Perennial Blooms Tall spikes of deep purple flowers in late spring to early summer, rebloom with deadheading Light Full sun Size 18 to 24 in. tall, 12 to 18 in. wide Hardiness Cold hardy in USDA zones 4 to 8
B) Artemisia Artemisia ‘Powis Castle’
Type Perennial Blooms Tiny, yellow-tinged silver flowers rarely bloom Light Full sun Size 2 to 3 ft. tall, 1 to 2 ft. wide Hardiness cold hardy in USDA zones 5 to 9
C) Allium Allium ‘Millenium’
Type Perennial Blooms Large 2-in. bright rosy-purple rounded clusters in mid- to late summer Light Full sun Size 15 to 20 in. tall, 10 to 15 in. wide Hardiness Cold hardy USDA zones 4 to 9
D) Cushion spurge Euphorbia polychroma
Type Perennial Blooms long-lasting chartreuse-yellow early spring bracts turn red, purple and orange in the fall Light Full sun Size 12 to 18 in. tall and wide Hardiness Cold hardy in USDA zones 4 to 8
E) Snow-in-summer Cerastium tomentosum ‘Silver Carpet’
Type Perennial; clusters of 1-in. white blooms in spring; full sun; 6 to 12 in. tall, spreading; cold hardy in USDA zones 3 to 7