From the garden ELLEN PEFFLEY
Last week’s column highlighted Snapdragons for annual spring color. This week the perennial Rudbeckia is recommended for summer color in the garden.
Rudbeckia can be purchase as mature plants but for gardeners who want to start their own they can be propagated from seed, divisions, or rhizomes but of these techniques, only divisions or rhizomes will develop a flowering plant this summer. Rudbeckia plants can be started from seed but to initiate germination seed need the process of stratification, cold treatment of 3 months at 40°F. Seed can be sown in the autumn to produce plants the following spring.
Divisions are made by dividing crowns and roots of established Rudbeckia plants. When foliage appears in the spring gently tease apart crowns with roots; replant immediately. Divisions should bloom in the same year in which they were separated.
Rhizomes are an easy method to propagate new individuals. Rhizomes of the Rudbeckia hirta variety ‘Goldsturm’ rhizomes are being sold in box stores and home improvement stores, found with other summer-blooming rhizomes and tubers. Several rhizomes come in each package. Gardeners who do not have established plants to divide and those who want a less expensive way to start plants, propagating from rhizomes is an economical way to grow plants.
Rhizomes can be started in a container. When shoots appear, transplant to the garden after the last spring freeze. Place young plants 12” to 18” apart in a location that gets full sun and in well-draining soil. Wide spacings will allow sturdier plants at maturity. Resist the urge to crowd them and the reward is a longer-lasting, showier floral display.
Rudbeckia is in the aster or sunflower family Asteraceae. Broad butter-yellow petals surround the dark brown center, which gives it the common name “black-eyed” Susan.
Rudbeckias are a short-lived perennial native to North America. Medium-sized, 2-inch flowers borne on tall, sturdy stalks bloom mid-summer until frost. Plants can grow to several feet in height. Their broad petals and nectar-filled centers attract pollinators. The broad petals are a landing spot for butterflies and the nectar draws bees.
Rudbeckias can be a resilient plant given the right environment. If plants are started from divisions or sprouting rhizomes, keep soil moist but not saturated. Maintain constant moisture until new leaves have formed, which is an indicator that new roots have developed. Removing spent flowers encourages continued blooms.
Ellen Peffley Harp, a retired professor of horticulture at Texas Tech University, writes about gardening for several Texas newspapers.
