Perennials for a Vertical Accent

Plants for Partial Shade

• Perennial, spring-flowering plants with vertical interest and grown in partial shade include Siberian iris “Caesar’s Brother” (Iris “Caesar's Brother”) and large yellow foxglove (Digitalis grandiflora). “Caesar's Brother” turns out deep-purple blossoms on rigid stems that are 3 to 4 feet tall. Also suitable for a full-sun site, this iris can grow in clay soil and on slopes. Large yellow foxglove grows 2 to 3 feet tall and is ideal for adding a vertical accent to a cottage garden; a dark background helps accentuate its light color. Both of these perennials are hardy in U.S. Department of Agriculture (USDA) plant hardiness zones 3 through 8.

Plants for Dry, Shallow, Rocky Soil

• Attract butterflies to the areas of your yard that have dry, shallow, rocky soil sitting in full sun by planting common sage (Salvia officinalis) and button snake root “Monarch” (Liatris ligulistylis “Monarch”). Common sage is a culinary herb that adds vertical interest to mixed borders or naturalized plantings; it is hardy in USDA zones 4 through 8. The Mediterranean perennial grows 2 to 2 ½ feet tall and forms short spikes of lavender-blue blossoms in spring. Button snake root “Monarch” supplies a vertical accent in summer and fall with its rose-purple, thistlelike blossoms atop 2- to 3-foot-tall stems. Monarch butterflies are especially attracted to this perennial that is hardy in USDA zones 3 through 8.

Very Tall Varieties

• The long spikes of flowers on certain very tall perennials can be eye-catching vertical accents. Culver’s root (Veronicastrum virginicum) exhibits 4- to 7-foot-tall, tapered spikes of white flowers in spring and summer. This northeastern North American native is hardy in USDA zones 3 through 8 and performs best in moist to wet soil. Giant desert candle begets pale-pink bottlebrush flowers on 3- to 4-foot-long spires atop stems that are 5 to 10 feet tall. It is used as a cut flower. This bulb plant is hardy in USDA zones 5 through 8.

Ornamental Grasses

• Ornamental grasses add considerable vertical effect to landscape designs and provide texture. The blue-green blades of switch grass “Dallas Blues” (Panicum virgatum “Dallas Blues”) form a dense, upright clump 4 to 6 feet tall. The plant's plumelike flowers exhibit a purple tinge and come out in fall to winter. Noted for vertical lines and slightly arching, 3-foot-tall blades, feather reed grass (Calamagrostis x acutiflora "Karl Foerster") puts out pinkish-purple, feathery plumes in spring; they grow 6 feet tall and persist into winter. Both perennial grasses are hardy in USDA zones 5 through 9 and tolerate air pollution, wet soil and black walnut trees.