The National Garden Bureau is calling 2016 “The Year of the Delphinium” and I agree. Delphiniums bring coveted blues, deep purples, pinks and whites to the garden, not to mention they are pollinator magnets. These stand-out perennials (hardy to USDA zone 2) got their name because ancient Greeks thought the spur on the back of the flower resembled a dolphin’s snout (the Greek word for dolphin is delfini.) In the south, these flowers are grown as annuals because they don’t perform well in prolonged heat and humidity (much like myself). Delphiniums are excellent cut flowers with a variety for every application. I love both heirlooms we carry—the traditionally tall 3’–6’ Pacific Giant, and the short and sweet Butterfly Blend that reaches just 12”–16”. Both are deer-resistant. Their close, more delicate cousin, larkspur, can be used similarly, and also comes in some hotter pinks and reds.
I prefer to start most perennials, including delphiniums, early and indoors, because I am more likely to get blooms the first season. You can start most perennials extra early (10 to 12 weeks ahead of your average last spring frost), although they may need to be potted up into larger containers once or twice before you transplant them outside. Delphiniums in particular should be started no later than 6 weeks ahead of your average last spring frost. Soaking seed for 8 to 12 hours can help speed germination, as well as darkness; so bury seeds ¼” when you sow. Also, delphiniums germinate best in soil temperatures of 70°–80°F—a tall order for our cool spring soil, which is another good argument for starting them indoors. Delphinium seeds should be fresh, as they are a species that doesn’t hold over as long as some others.
These extra steps will reward you come late spring! Pacific Giant spires look stately planted in odd numbers of clumps in the back of my sunny flowerbed. Their sculptural form adds structure to the bed and helps guide the eye. Despite being straight and tall, the petals and leaves are lacy and soft, adding a delicate touch. I prefer to stake mine since we can get some big winds here on the Colorado Front Range. After they flower, you should cut them back, fertilize with a phosphorous-rich, liquid fertilizer, and you will often get a second flush of flowers. I cut them down again at the end of the season and thank them for their spectacular display one last time. Next spring, look for the strongest 2–3 shoots in a crown and cut out the others; this is a good time to fertilize with a balanced, or phosphorous-rich liquid fertilizer. Dividing clumps every 1 to 3 years or so can also keep these cool-hued beauties from overcrowding so they can look their best.
Perennials are known for demanding a little more patience to see their full potential, but the up-front effort has long lasting results. Remember, if you don’t want to wait a year for blooms, sow extra early indoors to increase your chances of seeing that first year color. Once established, perennials give years of beauty with minimal maintenance, and are great when used to give a garden consistent structure. Growing perennials from seed is also advantageous because it gives plants time to grow up in your garden and adapt rather than being spoiled in a greenhouse, and in my case, shocked by the real world garden. Plus, buying seed versus potted plants really stretches one’s garden budget! The countdown to spring continues!