Cliveden Beauty is the hardiest delphinium you can grow, thriving in zones 3 through 7 with the robust constitution of a true belladonna hybrid. This open-pollinated cultivar reaches 30 to 36 inches tall with a compact, bushy habit that needs minimal fussing, producing tall spikes of summer blooms from June through August. Cut flowers last remarkably well when harvested at the right stage, and the plant rewards you with a second flush of blooms in late summer if you deadhead promptly after the first show. Deer leave it alone, and pollinators flock to its flowers.
12
Partial Shade
Moderate
3-7
36in H x 18in W
—
High
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The hardiness factor sets this apart from temperamental delphinium cousins. Most delphiniums demand coddling in cool climates, but Cliveden Beauty handles cold winters down to zone 3 with genuine toughness. The flowers emerge over a long window from early to midsummer, and cutting them for arrangements actually encourages a second bloom cycle in fall, rewarding you twice for one planting. The belladonna genetics give it a bushier, more manageable form than the towering hybrid delphiniums, so it needs less staking and still reaches a useful 30 to 36 inches.
Cliveden Beauty excels as a cut flower; floral designers prize the tall, sturdy stems and long vase life. Harvest when roughly one-quarter to one-third of the flowers on the stem are already open, then place immediately in water to maximize longevity. The blooms are excellent for mixed arrangements, and gardeners who cut regularly trigger that rewarding late-summer rebloom.
No timeline data available yet for this variety.
Start seeds indoors 8 to 10 weeks before your intended transplant date. Sow seeds 1/8 inch deep in a sterile germinating mix blended with vermiculite to prevent fungal problems. Keep the germination medium moist and maintain temperatures around 65 to 70°F; darkness aids germination. Expect sprouting in 10 to 30 days. Transplant seedlings into larger cell packs or 3 to 4-inch containers 6 to 8 weeks after germination and grow them at 50 to 55°F in a greenhouse or cold frame.
Harden off seedlings gradually before moving them outdoors after your last frost date. Transplant into garden beds or raised beds spaced 12 inches apart. If growing in a greenhouse, you can transplant plugs into raised beds in August through September for an extended season.
Direct sow in early summer where the plant is to grow.
For cut flowers, harvest when one-quarter to one-third of the flowers on the stem are already open. Cut in the early morning and place stems immediately in water to maximize vase life, which typically extends well beyond other delphinium varieties.
Cut back flower spikes immediately after the first bloom fades to trigger a second flowering in late summer and early fall. This variety rewards aggressive deadheading with abundant rebloom.
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