A Riot of Rudbeckias

By Colleen O'Neill Nice

Last July, my mom and I embarked on our first day-long coach tour sponsored by the Buffalo National Garden Festival. We visited several, diverse gardens in the southtowns of Buffalo including an exuberant landscape sprawling several acres. Welcoming fields of color greeted us in the bright afternoon sun. Immense daisy-like blooms of brown-eyed susans, in hues of yellow, gold, orange, bronze and red, glowed amid the colorful daylilies. With little rainfall and no supplemental irrigation, these plants were blissfully thriving in full sun with minimal water. I was immediately captivated by the flamboyant flowers. I needed to find out more.

A native to North America, rudbeckia is a genus of 23 species including annuals, biennials and perennials. Most gardeners are familiar with Rudbeckia fulgida ‘Goldstrum’, the perennial black-eyed susan that flourishes throughout summer and fall. Newer varieties of rudbeckia have been introduced in the past several years featuring large flowers in vibrant colors. Primarily considered annuals or short-lived perennials, they are members of the largest species ‘hirta’. These new hybrids, commonly referred to as gloriosa daisies, are drought-tolerant, sun-loving, prolific bloomers, easy to grow and self sow. Simply dazzling!

Annual Rudbeckias
One of my favorites, ‘Autumn Colors’ delivers the largest blooms ever grown on a gloriosa daisy. It’s maroon center is accented by fiery petals of orange, gold and mahogany. Unique color patterns dominate five to seven inch blooms. Strong stems grow 20 to 24 inches tall and 12 to 15 inches wide. ‘Autumn Colors’ won the Fleuroselect Quality Mark, Europe’s highest award for flowering ornamentals from seed. Although stunning in the garden, it’s long-lasting blooms are a must in a vase.

For an outstanding mix of double flowers shaped like pompons, stars and water lilies, try ‘Cherokee Sunset.’ Autumn shades include orange, gold, red, bronze and brown. Strong, well branched thirty-inch stems bloom from July until frost. It self sows easily on bare soil and should be spaced twelve inches apart to allow for good air circulation. A Fleuroselect winner, it was chosen for superior breeding, beauty and performance by the International Organization for Ornamental Plants.

Imagine a spectacular rudbeckia in shades of red and maroon with a big black eye. The first-ever, crimson flowering black-eyed susan from seed, ‘Cherry Brandy’ is blanketed with three to four inch blooms from summer through fall. Very strong stems, just two feet tall, support dozens of blooms which bees and butterflies adore. To stimulate constant blooming, deadhead plants throughout the summer as needed. Allow the last flowers of autumn to dry completely on the plants to encourage reseeding. ‘Cherry Brandy’ seedlings are slow starters, so be sure to start these seeds indoors in early to late winter.

Scrumptious, dark chocolate centers contrast with the bright orange tips of ‘Orange Chocolate.’ This new color combination is unique and stunning. Plants grow 24 inches tall and 18 inches wide in sun or part shade. They are deer resistant, suitable for xeriscaping and self sow freely.

Just 18 inches tall, ‘Corona’ is compact and densely branched with large, semi-double yellow petals surrounding a brown cone. It thrives in well drained, average soil in full sun. It’s crisp blooms pair well with the mottled flowers of ‘Autumn Colors’ or the vivid shades of ‘Cherry Brandy’.

Easily propagated from seed, ‘Marmalade’ germinates in ten to fifteen days. Plants produce large, five inch blooms of orange-yellow petals surrounding prominent brown cones. It is reliable and a good choice for novice gardeners. ‘Marmalade’ grows quickly (two feet tall) and blooms prolifically if watered regularly, especially throughout hot summers.

Dwarf Rudbeckias
For small gardens and containers, several petite varieties are available. ‘Goldilocks,’ in development for over twelve years, displays plentiful large double and semi-double canary-colored flowers. Just eight to ten inches tall with a bushy habit, it produces a mass of color for months. Often used in public spaces, this little powerhouse blooms under extreme conditions.

‘Becky’ grows ten to twelve inches tall with orange, yellow and cinnamon bicolor flowers. Combine it with the bright yellow petals and a floriferous disposition of ‘Becky Yellow’. Add the rusty-red colored centers of ‘Becky Cinnamon BiColor,’ surrounded by petals of yellow, orange and mixed hues. All love full sun and will reseed gently. Their offspring may not be as short as the parents. Butterflies and bees are attracted to the well branched plants that bloom from late spring until fall with regular deadheading.

Ideal for window boxes, rock gardens and the front of the border, ‘Toto Lemon’ bears three inch pastel yellow daisies on stout, very erect stems. It maintains it’s color and shape remarkedly well for drying. To extend bud production, remove dead blossoms regularly. Just under a foot tall, ‘Spotlight’ has a charming chocolate-brown dollop on every slightly fluted petal. Very weather resistant, it focuses all its energy on good branching and producing new buds. The most compact dwarf rudbeckia, it grows six to eight inches tall and ten inches wide.

The fluffy, zinnia-like blooms of ‘Maya’ are sunny-yellow with green centers. A pioneer in double flowered dwarf rudbeckias, it is a perennial in zones 5-9 and grows just eighteen inches tall. It was awarded a Fleuroselect Gold Medal for compact plant habit and excellent garden performance after trials in more than forty public gardens across the United States, Europe and Asia. Ornamental seed heads can be left intact for winter interest.

Perennial Rudbeckias
The light green cones of ‘Prairie Sun’, surround orange-yellow rays brushed with lemon-citrus tips. Masses of long-lasting flowers with hues reliably consistent create bold accents in the garden or containers. The three foot tall plants will tolerate clay soils, but prefer organically rich loams. ‘Prairie Sun’ received both the All-American Selection and Fleuroselect Gold Medal awards in 2003 for stunning petal color combination, upright stems and excellent weather resistance. Grown as a perennial in zones 3 to 8, it can be started indoors from seed in late February or early March.

To commemorate their 150th anniversary, the city of Denver developed the ‘Denver Daisy.’  The signature plant is a cross between the native Rudbeckia hirta and the award winning ‘Prairie Sun’. Seeds were distributed to the public through schools, offices and organizations to help beautify the city. Huge six-inch pure yellow blooms, marked with a prominent rich mahogany eye, surround a black central cone. Compact and bushy, this drought resistant perennial (zones 3-9) flowers for months on strong stems that won’t flop, even in inclement weather. It grows 18 to 20 inches tall and 10 to 18 inches wide. It received the 2010 American Garden Award grand prize for its large, long-blooming flowers, extreme heat tolerance and pest resistance.

Bright splashes of gold, copper and brown petals highlight the vigorous Fleuroselect gold medal winner, ‘Cappuccino’. Uniform, well-branched plants grow 18 to 20 inches tall and 14 to 16 inches wide. It is a cut-and-come plant, so the more you cut, the more they bloom. Through breeding, these tetraploids have twice the chromosomes of other rudbeckias, giving them exceptional bloom strength. They are a hardy, long-lived perennial in zones 3-9.

The unique quilled flower petals of ‘Chim Chiminee’ in velvety, rustic shades are impressive in a butterfly garden or mailbox planting. This fast growing, multi-branching perennial is hardy in zones 3-9 and grows 24 to 30 inches tall. Flowers bloom from July until frost if watered weekly, especially in extreme heat.

Add a sprinkling of whimsy to your garden with ‘Irish Spring’. Yellow-orange rays surround a vivid green center disk creating five to seven inch daisy-like blooms. Basal clumps of bristly, olive-green leaves surround robust single flower stems. ‘Irish Spring’ blooms the first year from seed and is hardy in zones 3-8. It will also self-seed if given optimum conditions. It prefers moist, organically rich soil but grows well in average, well drained garden beds. 

Propagation
Rudbeckia are easy to grow from seed and are available at retail locations, through mail order and from internet seed sources. Some of my favorite on-line catalogs for rudbeckia seeds include Johnny’s Selected Seeds (www.johnnyseeds.com), Hazzard’s Seed Store (www.hazzardsgreenhouse.com), Select Seeds (www.selectseeds.com), Park Seed (parkseed.com) and T’s Flowers & Things (www.tsflowers.com).

For indoor propagation of annual rudbeckia, sow seeds six to eight weeks before your last frost date in a thoroughly moistened sterile, seed-starting mix. Put one to two seeds in each cell of the flat, pressing gently into the soil barely covering the seeds. Keep the tray in a warm location (70-72ºF is ideal for seed germination) until seeds sprout, usually five to fourteen days. Once the seedlings appear, place the flat under grow lights or near a sunny window. After two sets of leaves develop, seedlings can be thinned by pinching or cutting weak plants at the soil line. Tender seedlings need to be hardened off before they can be transplanted into the garden. Start by leaving plants outdoors in a shaded, protected location for about three to four hours. Over a seven to ten day period, gradually increase the time spent outdoors as well as the sun exposure. Perennial rudbeckia seeds started indoors can be placed in the refrigerator for four weeks, then moved to warmer temperatures, to improve germination.

For propagating rudbeckia outdoors, sow seeds directly in the garden when daytime temperatures reach 60ºF. Choose a site with well drained soil and full to part sun. Sow perennial rudbeckias in fall or early spring. Gently press seeds into the soil making sure they are not completely covered. Seeds need light and moisture to germinate. Keep seedbed consistently damp. As seedlings grow, thin plants to maintain good air circulation. The mature size of the plant determines the correct spacing. Allow eight to twelve inches between annual rudbeckias and 18-30 inches for perennial varieties. Plant dwarf varieties closer together, spacing plants four to six inches apart.  

Cultural Conditions
Most rudbeckias tolerate a wide range of well drained soils. Plants become weak and flowers flop when soils are too rich. Root rot is a problem if soils are too moist, so allow flower beds to dry out between waterings. All rudbeckias thrive in full sun. When grown in light shade, flowers may be smaller and fewer. They will tolerate dry conditions, but prefer consistent moisture.

Blooming begins in about ten to twelve weeks for annual rudbeckias and continues until frost. Perennial seeds planted in early spring will bloom the first year. To extend the flowering period, be sure to pinch off faded blooms at the base of the flower stem. To attract birds and encourage reseeding, leave seedheads intact during fall and winter.

Black-eyed susans are easy to grow, deer resistant and not plagued by disease or pests. If plants are crowded, leaves may develop powdery mildew during hot, humid weather. New seedlings in the garden may need to be transplanted to prevent crowding. Move thinned seedlings to another area of the garden or pot them up for neighbors or community plant sales. Perennial rudbeckias do not need regular dividing, however if plants become crowded, divide clumps in early spring just as growth begins. Watch for slugs and snails that like to eat the tender growth of seedlings.

Adaptable, gloriosa daisies thrive in containers, mixed borders, wildflower meadows, window boxes and cutting gardens. Mass planted or intermixed, combinations are endless. Pair their warm hues with the bluish-purples of Russian sage, liatris, salvia or fall blooming asters. Create stunning bouquets with the abundant blooms, which last up to three weeks in a vase.

Don’t let summer buzz by without enjoying rudbeckias in your garden. Grow them from seed or purchase plants at your favorite nursery.  Your only dilemna will be – which variety to grow? So move over ‘Goldstrum’ and make room for the new hirta hybrids!

So Move over 'Goldstrum' and make room for the new hirta hybrids!

Printed in the Upstate Gardeners’ Journal, May-June 2013