Black-Eyed Susans (Rudbeckia) Plant Profile

With there bright yellow petals and dark center disks, black-eyed Susans (Rudbeckia) have become garden staples. There is a great deal of variety within the species and most are true workhorses, with very few problems. The flowers are daisy-like and can be single, semi-double, and fully-double. You can tell them apart from coneflowers by their coarse-textured, hairy leaves. The most commonly thought of Rudbeckia is the traditional black-eyed Susan, a daisy-like flower with gold petals and a dark center seed head. It also has the well-known scratchy, hairy leaves, which are not one of its best features.

• Botanical Name: Rudbeckia
• Common Names: Black-eyed Susan, brown-eyed Susan, conedisk, conedisk sunflower, gloriosa daisy, tall coneflower
• Plant Type: Perennial flower or annual flower depending on species
• Mature Size: Species vary from dwarf 1 foot to giant 9 feet tall.
• Sun Exposure: Full sun
• Soil Type: Loamy
• Soil pH: 5.8 to 6.8
• Bloom Time: Summer to fall
• Flower Color: Yellow, orange, russet, bronze, mahogany
• Hardiness Zones: Varies, with perennial species usually hardy in zones 4, 5, 6, 7, 8, 9
• Native Area: North American meadow

Black-eyed Susans are easy to establish, naturalize well, and require little maintenance other than deadheading.

Rudbeckia plants work equally well as a complement to blue and purple flowers, like Russian sage and Veronica or mixed in with other jewel tones, such as sedum "Autumn Joy," purple coneflower, and New England asters. Rudbeckia also makes great cut flowers and even the seed heads will hold up well and look attractive in arrangements.

Regular deadheading of the faded flowers will keep the plants in bloom longer. You can let the last flowers of the season remain on the plants to go to seed and feed the birds, but you will also get a good deal of self-seeding, which might not be a bad thing.

Plant division is only necessary if the clump gets too large for its space or if you want to make more plants. Rudbeckias don’t generally die out in the center and don't require frequent division.

You will get the best flowering from your black-eyed Susan plants in full sun, but the plants can handle partial shade.

Black-eyed Susans are not particular about soil but do best in soil that is not too rich, with well-draining conditions.

Keep the plants well watered their first season, to get them established. Once established, they will be quite drought resistant.

The plant likes warmer temperatures of 60 degrees Fahrenheit and more. It handles both drought and humidity well.

Go easy on the fertilizer. Too much will result in weak stems and plants. A side dressing of compost should be all they will need.

Rudbeckia can be started indoors, from seed. Start seed about six to eight weeks before last expected frost. Perennial varieties will germinate best if the seed containers are kept in the refrigerator or similarly cold place for four weeks after seeding. Then move them back to a warm spot (70 to 72 degrees Fahrenheit) until the seeds actually germinate.

Black-eyed Susans can also be direct seeded in the garden once daytime temperatures remain around 60 degrees Fahrenheit. If you do not wish to start your own seed, seedlings and plants can be purchased and transplanted.

Most Rudbeckia varieties come in shades of yellow or orange, with a dark center seed head, but the flower heads are actually quite varied. There are Rudbeckia with petals in russet, bronze, and mahogany tones. For example, Rudbeckia "Cordoba" looks like a blanket flower. Rudbeckia "Maya" resembles a tall marigold and Rudbeckia "Cherokee Sunset" has an almost Chrysanthemum look.

The size of Rudbeckia plants varies greatly, from dwarf (1 foot tall) varieties like "Becky" and "Toto," to the giant Rudbeckia maxima, which can reach 9 feet tall. Growing conditions and weather also affect the mature size of plants.

• Rudbeckia fulgida var. sullivantii "Goldsturm" is the standard for Rudbeckia. It is long-blooming and virtually pest free. (2 feet tall)
• Rudbeckia hirta "Cherokee Sunset" has double and semi-double flowers in shades of yellow, orange, red, bronze and mahogany. It is short-lived but re-seeds itself. (2 feet tall)
• Rudbeckia hirta "Indian Summer" is traditional and daisy-like, with large yellow flowers. Short-lived, it re-seeds itself or you can grow it as an annual. (3 to 4 feet tall)
• Rudbeckia "Toto Rustic" is a dwarf plant in fall colors. There's also golden "Toto" and pale "Toto Lemon." (1 foot tall)

Rudbeckia plants are deer resistant once their leaves become coarse and hairy, but tender young growth may get nibbled.

Powdery mildew will affect the leaves in hot, humid conditions. Minimize this by planting in full sun and thinning the plants to allow for good air circulation.