Blue is a very calming and serene color. It is also considered a healing color that helps lower blood pressure and can reduce rapid heart rate. It is not surprising that shades of blue and blue-green are frequently used in healthcare settings. (Photo Pulmonaria ‘Blue Ensign’, courtesy of The Intercontinental Gardener)
Many gardeners, including me, have a penchant for blue flowers. Blue is also one of the preferred colors of bees. There are very few ‘true blue’ flowers. Below are some of my favorite perennials with ‘blue-tiful’ blooms, all of which are deer and rabbit resistant.
Delphinium. There are many different varieties in this genus, ranging from towering standouts like ‘Cobalt Dreams’ that can reach 6’, to dwarf varieties like ‘Summer Nights’, a bushy cultivar that grows between 10”-14”. The New Millennium series has been bred to have strong stems and better heat and humidity tolerance. Dwarf Delphinium are in the chinensisspecies. These are compact and bushy in habit, perfect for smaller spaces and where wind can be an issue. Delphinium grow best in full to part sun and in nutrient rich soil (soil amended with compost or other organic matter). Wet soil (especially in winter) is the death of them. Hardiness range 3-7 (Photo Delphinium ‘Summer Cloud’, Bluestone Perennials)
Gentiana The Gentian genus is quite large (almost 400 species) but almost every member has glorious blue flowers. Gentians thrive in fast-draining soil and do best in regions with cooler summer weather. Most Gentians have trumpet-like flowers but there are also bottle-nose Gentians (G. andrewsii) with closed flowers that only strong insects like Bumblebees can pry open to access nectar. Gentians bloom in summer or fall depending on the species and range in light preference from sun to shade. Some species, like acaulus, are a ground-hugging matt, growing only 4” tall, while ‘True Blue’ (15”-20”) and ‘Marsha’ (18”-23”) are taller beauties. Hardiness range 3-7. (Photo taken at Coastal Maine Botanical Garden)
Brunnera Commonly called Siberian Bugloss, this three-season interest perennial has airy sprays of striking blue flowers in spring (the rarely available ‘Betty Bowring’ has white flowers). The attractive heart-shaped foliage can be green, silver or variegated. ‘Sterling Silver’ is said to be an improved version of ‘Looking Mirror’. ‘Sea Heart’ has received praise for being a better choice in areas with high heat and humidity. I started trialing ‘Jack of Diamonds’ this spring and have been very impressed with its massive leaves (I obtained it after it finished flowering). Brunnera enjoys part shade to shade in Zones 3-8.
Iris My favorite species in this large genus are Japanese, Siberian, German Bearded, reticulata and Louisiana Iris. These offer wonderful choices for dazzling blue blooms. I now grow mostly Japanese and Louisiania Irises. I love their large ‘winged’ blooms and I find them less maintenance overall. Siberian and German Bearded are very drought tolerant while Japanese and Louisiana Iris prefer a more moisture-retentive soil. Japanese Iris also need acidic soil – high pH is the death of them. ‘Iris x robusta ‘Gerald Darby’, a hybrid between two native species (Iris versicolor x Iris virginica), has sweet violet-blue flowers but I grow it primarily for its eye-catching smoky-purple foliage in spring. All do best in full sun. Schrieners Iris Gardens is a well-rated mail-order company in Salem, Oregon. It has many gorgeous blue irises, including ‘Sinfonietta’ (pictured). Hardiness range 3 -9
Meconopsis Himalayan Blue Poppy can be likened to the ‘Holy Grail’ by many gardeners. The plant is not long-lived and usually waits to bloom until its second or third year. Himalayan Blue Poppy has the well earned reputation of being very challenging to grow and has been my personal challenge for years. I refuse to give up in my quest for this elusive blue gem in the garden. Bragging rights are appealing. Hardiness range 5 – 8
Other perennial genus with ‘blue-tiful’ flowers include Campanula, Echinops, Baptisia, Stokesia, Geranium, Aconitum, Veronica, Pulmonaria and Ceratostigma.