Black-Eyed Susan is a sturdy bloomer all through the summer months. Some of the varieties are longer-lived perennials than others. The variety Rudbeckia hirta and all of its developed cultivars (‘Toto Gold’, ‘Sonora’, etc) grow more like a biennial plant: the first season they grow foliage, and the second, they flower in order to set seed for future generations. After the second year, they die off at the end of the summer. The perennial varieties will return year after year to bloom profusely with minimal maintenance. Plants that aren’t flowering can be encouraged to bloom with a variety of techniques.
Common Reasons Why Black-Eyed Susan Isn’t Blooming
There are a few reasons why Black-Eyed Susans might fail to bloom heavily or even at all: inadequate sun exposure, spent blooms, crowded conditions, or too much nitrogen. Full sun sites can become partly shaded or even fully shaded when surrounding trees and/or larger shrubs mature and cast shade on the lower-growing plants. Houses and other structures can shade flower beds for longer than expected at certain times of the year, depending on the angle of the sun.
Not deadheading Black-Eyed Susans regularly will slow down blooming. The plant will put energy into producing seed instead of more flower production. Keep your plant deadheaded all summer to prolong the blooming period.
Black-Eyed Susans that have outgrown their garden space or pot will need to be divided and replanted. Dividing up clumps will help to reinvigorate plant growth and get rid of any root mass that has died off. Plants growing too close together have to compete for sunlight, water, and nutrients and will struggle to produce flower stems.
Overfeeding Black-Eyed Susan will not encourage more blooms. The plant will produce masses of tender young foliage at the expense of flowers, making it vulnerable to attacks from sap-sucking pests such as aphids.
Pruning Black-Eyed Susan To Help It Bloom
Deadheading is the pruning technique that will help Black-Eyed Susan to continue to produce blooms throughout the summer months. Make sure to cut the flower stem back to the next set of leaves. This will hide any bare stems while encouraging more flowering shoots to form.
Fertilizing Black-Eyed Susan To Help It Bloom
Rudbeckia will not bloom more if it is fed large amounts of prepared fertilizer. Mulching in the spring and fall with an organic compost or shredded leaves will slowly release nutrients to the soil that the plants can take up when necessary. Using fertilizers with high nitrogen levels will encourage foliage growth at the expense of flowers.
Why Black-Eyed Susan Isn’t Blooming
- Not planted in full sun
- Not deadheaded on a regular basis
- Needs dividing or repotting
- Overfeeding with a fertilizer high in nitrogen
Author Robbin Small - Published 7-31-2022