Black-eyed susan (Rudbeckia hirta)

Also known as: English bull's eye, Gloriosa daisy

The Black-eyed Susan is a yellow and black flowering plant known for its curved leaves. It's culturally significant in the Southern United States and is commonly planted to attract butterflies to gardens. Over time, it has spread across North America and many other parts of the world. This flower is recognized as the state flower of Maryland and holds historical importance for the University of Southern Mississippi.

In This Article

Care Tips Water Sunlight Temperature Soil Fertilize Prune Propagation Repotting

Attributes of Black-eyed susan

Lifespan

Perennial, Annual

Plant Type

Herb

Plant Height

30 cm to 1 m

Spread

30 cm to 45 cm

Leaf Color

Green

Flower Size

5 cm to 10 cm

Flower Color

Yellow Orange Red Gold

Images of Black-eyed susan

Quickly Identify Black-eyed susan

Dark brown central cone surrounded by bright yellow ray florets

Egg-shaped central dome with vibrant orange-yellow to deep red rays

Dry cypsela fruit with small, oblong shape and rich brown seeds

Distinctive winged petiole with hairy, veined leaves and serrate margins

Grooved, bristly stem reaching 1-2 feet in height, simple or with limited branching

Scientific Classification of Black-eyed susan

Phylum

Vascular plants

Class

Dicotyledons

Order

Asters bellflowers fanflowers and allies

Family

Daisy

Genus

Coneflowers

Species

Black-eyed susan

Planting and Growing of Black-eyed susan

Care Difficulty

Easy

Watering Schedule

Every 4 days

Sunlight Requirements

Full sun

Sunshine Duration

10-12 hours

Ideal Temperature

65-75℉

Soil Type

Potting Mix, Peat Mix

Soil pH

6.5-7.5

Fertilizer Type

Balanced

Pruning Season

Spring, Summer

Pruning Area

Branches, Leaves

Pruning Frequency

Once a year

Repotting Season

Spring

Pot Type

Plastic, Ceramic

How to Water Black-eyed susan?

Rudbeckia hirta, known for its bright, daisy-like flowers, prefers consistent moisture but can tolerate short dry spells. Water it until the soil is moist down to a depth of about 6 inches, ensuring that it isn't overly saturated. Watering with approximately 500 ml per session is generally sufficient, though adjustments might be necessary based on weather conditions.

What are the symptoms of an underwatered Black-eyed susan? ›

What should I do if my Black-eyed susan is not getting enough water? ›

What are the symptoms of an overwatered Black-eyed susan? ›

How to save an overwatered Black-eyed susan? ›

More About Watering Techniques→

What Are the Sunlight Requirements for Black-eyed susan?

Sunlight Requirements: Full sun

Duration of light: 6 to 8 hours

For optimal growth, Rudbeckia hirta should be given full sun conditions, ensuring ample blooming and vibrant foliage, which improves garden aesthetics.

What is the ideal light setting for Rudbeckia hirta? ›

How to achieve ideal lighting for Rudbeckia hirta? ›

What benefits does Rudbeckia hirta receive from ideal lighting? ›

More About Sunlight Requirements Techniques→

What Is the Ideal Temperature Range for Black-eyed susan?

Ideal Temperature: 65 ~ 75℉

The ideal temperature range for cultivating Rudbeckia hirta is between 65°F and 75°F. This range ensures optimal growth and blooming conditions, allowing the plant to thrive by facilitating proper metabolic processes. Maintaining this temperature helps in promoting vibrant flower production and healthy foliage. Cooler or warmer than this range can slow growth and reduce blooming potential.

What Soil is Best for Black-eyed susan?

Soil type: Sandy loam, Loam

Soil PH: 6.5 ~ 7.5

Rudbeckia hirta thrives in well-drained soil, preventing root rot and promoting healthy growth. Ensure excess water can easily escape to maintain optimal moisture levels. Although not very demanding, a soil mixed with organic matter boosts Rudbeckia hirta's flowering potential, ensuring vibrant blooms by providing essential nutrients. This plant prefers consistent moisture without being waterlogged. Adequate soil moisture supports lush foliage and extended blooming periods. More About Soil→

How to Fertilize Black-eyed susan?

Fertilizer type: Balanced

For Rudbeckia hirta, it's important not to overwhelm the plant with excessive nutrients. When applying liquid fertilizer, aim for a solution that's diluted to half the recommended strength on the product label, focusing on even coverage over the root zone. More About Fertilizing Techniques→

How to Prune Black-eyed susan?

Pruning Time: Spring, Summer

Throughout the growing season, cut back the faded flowers to the nearest leaf node. This practice, known as deadheading, prevents the plant from going to seed and encourages more blooms for a prolonged display. As blooms wind down towards late summer, feel free to prune the plant by cutting back the stems by about a third. This not only tidies up the plant but also encourages a fresh flush of late season growth in some climates. More About Pruning Techniques→

How to Propagate Black-eyed susan plant?

Propagate Time: Early spring,Spring

Begin by filling seed trays with a quality seed-starting mix. Sow the Rudbeckia hirta seeds on top of the mix and lightly cover them. Keep the trays in a warm, sunny location indoors until the seedlings are ready for transplanting.

Before dividing the plant, water it thoroughly to ensure roots are moist and less likely to break. Dig up the entire plant and carefully separate the root clumps into smaller sections, making sure each section has several shoots.

Once the seeds have germinated and grown into small plants with several leaves, transplant them into larger pots or directly into the garden, ensuring they have enough space to mature and adequate sunlight.

More About Propagating Techniques→

How to Repot Black-eyed susan plant?

Repotting frequency: Every 1-2 years

Rudbeckia hirta usually needs repotting when its roots outgrow the current container, causing it to become root-bound. You'll notice it requires more frequent watering or if the roots are peeking through drainage holes. The active growth in spring and summer is ideal for repotting, ensuring minimal stress.

Select a pot that is one size larger than the current one, ensuring it has drainage holes. A pot too large can retain excess moisture, risking root rot, while an appropriate size aids root expansion and stability. The material can be clay or plastic; clay offers better breathability, but plastic retains moisture longer.

Choose a well-draining potting mix to prevent waterlogging, which can be detrimental to Rudbeckia hirta. A mix containing peat, perlite, and a bit of sand provides the perfect aeration and drainage, promoting healthy root growth and preventing nematode build-up.

More About Repotting Techniques→