Gentians are prized for their tubular flowers in intense blue shades. Many are considered difficult to grow, but G. asclepiadea needs little more than consistent moisture and humus-rich soil with excellent drainage. Some require lime-free soil, as noted. Well worth the extra care, as they produce some of the richest blues in the garden.
Native to Europe and western Asia. Arching, large-leafed stems form a clump 2–3 ft. tall and 1 1/2 ft. wide. In late summer and early fall, rich, deep blue, 1 1/2-in., trumpet-shaped flowers open into stars atop the stems and among the upper leaves. Thrives in rich, neutral to acidic soil; makes a choice companion for ferns. Partial shade.
From Turkey and Iran to central Asia. Arching or sprawling stems 9–18 in. long form a spreading leafy mass about 8 in. high and 1 ft. wide. Clusters of 2-in., dark purplish blue flowers appear in late summer. G. s. lagodechiana, the form commonly sold, is similar but has more widely spaced flowers.
Native to Japan. Grows to 4 ft. tall and 2 ft. wide, with grayish green leaves and pink flower spikes ...
To 2 ft. Dwarf with tiny leaves that emerge bluish, take on rust tones. Blue-purple flowers in early m...
Grows to 2–3 ft. tall, 6 ft. wide. Macedonian native; considered the hardiest common boxwood.