Friday, June 29, 2012

Rudbeckia - Where Black-Eyed Susans Grow

Rudbeckia 'Spotlight'
One of my earliest heart-felt memories of early childhood is of walking in our front yard overlooking the river waist-deep in Black-Eyed Susans. Now the sight of them anywhere recalls those halcyon days. And there are many reminders, for Black-Eyed Susans are native to North America. According to the USDA PLANTS Database, there are few states where at least one species can't be found in the wild.

It's believed that English colonists gave the flowers their common name inspired by a popular romantic poem of the time, Black-Eyed Susan by John Gay (1685-1732).

ALL in the Downs the fleet was moor’d,
  The streamers waving in the wind,
When black-eyed Susan came aboard;
  ‘O! where shall I my true-love find?   
Tell me, ye jovial sailors, tell me true
If my sweet William sails among the crew.’   

William, who high upon the yard
  Rock’d with the billow to and fro,
Soon as her well-known voice he heard
  He sigh’d, and cast his eyes below:
The cord slides swiftly through his glowing hands,
And quick as lightning on the deck he stands.

Then the lovers embraced,

The noblest captain in the British fleet   
Might envy William’s lip those kisses sweet.

Sweet William commenced to assure her that he would be safe even in battle, and true to his vows. Finally,

The boatswain gave the dreadful word,
  The sails their swelling bosom spread,
No longer must she stay aboard;
  They kiss’d, she sigh’d, he hung his head.
Her lessening boat unwilling rows to land;
  ‘Adieu!’ she cries; and waved her lily hand.

Perhaps the memories of parting and the colonists' own travels came to mind.

The naming of genus Rudbeckia (pronounced rud-BEK-ee-a) isn't so romantic, but worth knowing. It was named for Olof and son Olof Rudbeck, well-known Swedish scientists of the 17th and 18th centuries. Olof the Elder, (1630-1702), also known as Olaus, was best known for his work in medicine and linguistics, but also for his accomplishments in botany, astronomy and music. A professor at Uppsala University, he established Sweden's first botanical garden there. It became known as Rudbeck's Garden.

Olof the Younger (1660-1740) continued in his father's footsteps, succeeded his father's professorship at Uppsala, excelling in ornithology, botany and linguistics. One of his best-known students was another famous Swede, Carl Linneaus (1707-1778), the botanist who devised our system of taxonomy. Quite naturally, Linneaus honored the Rudbecks in the genus Rudbeckia. Rudbeck's Garden was later re-named Linneaus Garden.

Of the 30 or so Rudbeckia species, I admire a few particularly.

Rudbeckia hirta may be the most common. It grows almost everywhere unplanted and untended. You'll find it along roadsides, in fields, and maybe wild in your yard, too. You've probably picked them for bouquets. There are several varieties. Rudbeckia hirta var. pulcherimma is hardier than the rest. You'll find it growing from Florida to Canada. It's mostly biennial at best, meaning that it flowers the second year and dies. In the south, R. hirta may flower the first year and die, but not before it re-seeds itself. In fact, that's the beauty of Rudbeckia hirta; it's easy to start from seed. Perfect for planting your own wildflower meadow.

Rudbeckia hirta has been used medicinally for many years. It's said to boost the immune system, so was used to treat various infections.

Maybe you remember the Gloriosa Daisy. I do. It was a big hit when introduced back in the 1950s. Gloriosa Daisy resulted as an attempt to perennialize R. hirta. That didn't work. But Gloriosa Daisy is still popular because the flowers are much larger than the species, in nice mixtures of colors, and sometimes double. It's ideal for naturalizing. I also remember my mother being disappointed that Gloriosa Daisy didn't return year after year.

Several new Rudbeckia hirta cultivars have been introduced recently promising longer than biennial lives. The jury is still out. Don't count on Rudbeckia hirta as a perennial yet, but enjoy it for what it is. Gloriosa Daisy is hardy in USDA climate zones 5 to 10.

Rudbeckia fulgida 'Goldsturm'
If you want a dependable native perennial that looks like Rudbeckia hirta, plant Rudbeckia fulgida or it's offspring. R. fulgida is the honored grandparent of most hybrid perennial Black-Eyed Susans. Its various varieties are the parents. These varieties are distinguished by slight differences. Plant producers look to those differences to selectively breed into new hybrids.

Rudbeckia fulgida var. sullivantii is the parent of the most popular Black-Eyed Susan, Rudbeckia fulgida var. sullivantii 'Goldsturm'. Developed in Germany, the name means "gold storm." It certainly is. The flowers are golden yellow, large and abundant, appearing for weeks from mid-summer to fall. It's so tough, you'll find it in planting beds around gas stations and shopping malls. Not surprisingly, it was named the 1999 Perennial Plant of the Year by the Perennial Plant Association. R. fulgida var. sullivantii is hardy in USDA climate zones 3 to 9.

Rudbeckia fulgida var. speciosa is almost exactly the same as var. sullivantii, but shorter. Common names include Eastern Coneflower, Orange Coneflower, Showy Coneflower. 'Viette's Little Suzy' is one to look for. 'Little Suzy' is named after a family of plant hybridizers in the U.S. R. fulgida var. speciosa is hardy in USDA climate zones 4 to 8.

(Note that the common name, Coneflower, is also shared with the related genus, Echinacea. They are not to be confused, though some Echinaceas were once named among the Rudbeckias. .)

Rudbeckia lacinata, known as Cutleaf Coneflower, is a tall one, sometimes growing 9 feet high. The large flowers with drooping petals are light lemon yellow. It's too tall for planting in the front of perennial beds, but perfect for planting in the rear. The petals fluttering in the breeze add motion and interest to the border. The disadvantage of its height is that it needs support to keep it from falling over.

Back in 1894, a seedling of R. lacinata named 'Golden Glow' was introduced to an appreciative gardening audience. Showy double blooms and shorter height (about 5 feet) made it very popular. But like its parent, it also needs support. 'Golden Glow' is still available, but superseded by an offspring named R. lacinata 'Golden Drop.' 'Golden Drop' only grows to 3 feet. If you want to plant a "heritage" garden featuring old-fashioned, heirloom species, Rudbeckia lacinata is a "must have." It's hardy in USDA climate zones 4 to 8.

Rudbeckia maxima
Rudbeckia maxima, also known as Great Coneflower and Cabbage Leaf Coneflower, grows to 6 feet. The medium yellow flowers sport prominent cones. It's native to Texas and surrounding Gulf states. Rudbeckia maxima is known to be hardy in USDA climate zones 6 to 8.

Rudbeckia nitia is tall, like R. lacinata and R. maxima, but the large, golden yellow flowers have green centers. It's commonly called Shining Coneflower. R. nitida should be considered a protected species, so don't collect it from the wild. From it, plant breeders have produced a wonderful new plant called 'Herbstsonne.' 'Herbstsonne' means "autumn sun." Enormous flowers on tall 6 foot plants really attract attention. This, too, is perfect for height and drama in the perennial border. 'Goldquelle' is a shorter version with double flowers. 'Goldquelle' means "bonanza". It deserves the name. R. nitida is hardy in USDA climate zones 4 to 10.

Rudbeckia subtomentosa is another desirable species. It's commonly called Sweet Black-Eyed Susan. You'll find it growing wild in the central United States. Height is about 4 feet. The flowers are especially fragrant. 'Henry Eilers', a cultivar, displays large golden blossoms with tubular petals, somewhat resembling yellow wagon wheels. R. subtomentosa is hardy in USDA climate zones 4 to 10.

Rudbeckia triloba
Rudbeckia triloba, commonly known as Three-lobed Rudbeckia or Brown-eyed Susan, is very hardy, thriving in USDA climate zones 3 to 10. Bright yellow flowers with big brown centers really attract attention. Plants grow to 4 feet. Two cultivars, 'Prairie Glow' and 'Red Sport' produce bright orange flowers with yellow tips.

Rudbeckias perform best in full sun, but will tolerate partial or light shade. Soils should be well-drained soils with pH ranging from 5.6 to 7.5.  Take a soil sample to your nearest Cooperative Extension Service office for proper analysis.

Prepare the planting bed by cultivating at least 6 inches deep, removing all traces of weeds. Compost may be incorporated into the soil.  Incorporate 10-10-10 fertilizer at a rate of no more 2 lbs. per 100 square feet into the top 4 inches to 6 inches of soil. Avoid synthetic fertilizers contacting any part of your plants.

If planting seed, sow according to instructions on the seed packet.

If planting container-grown plants, space larger ones 24 inches to 36 inches apart. Dig planting holes into the cultivated soil a little less deep than the depth of the growing container.  Water the plants in the pots, then drain.  Place the plants into the holes and back-fill, watering as you go. Press soil around the root balls. Do not cover entirely the root balls with soil. The tops should be slightly exposed. Add a top-dressing of mulch around the plants, not on top of them, about 1 inch deep.

Plant Rudbeckias with other plants having similar cultural requirements.  Fertilize sparingly and allow soil to dry between watering.

All Rudbeckias attract butterflies. Birds get enthusiastic about the seeds. All Black-Eyed Susans are reasonably drought-tolerant. They're especially suited to naturalizing, wildflower meadows, cutting gardens, wildlife gardens, native plant collections, heritage and cottage gardens. But they're wonderful in any perennial garden or border, even at gas stations and shopping malls.

Where should Black-Eyed Susans grow? Probably in your garden. Certainly in your heart.

Buy Rudbeckia at

Rudbeckia hirta 'Prairie Sun'

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