Guest Author - Connie Krochmal
When choosing perennials for the cutting garden, we often prefer those that are hardy and low maintenance. The black-eyed Susans are an excellent choice. These stems are perfect for late summer bouquets.
Black-eyed Susans have large yellow or orange blossoms with prominent black or brown cones in the center. That is why they are sometimes called coneflowers. These daisy-like blooms can be used as a mass flower or as an accent.
In the U.S., there are at least 30 species of black-eyed Susans. Less than ten of these are commonly seen in cultivation.
When buying seeds for your cutting garden, be aware that one species, Rudbeckia hirta, is best grown as an annual. This one tends to die out the second year. This is commonly known as the gloriosa daisy.
Black-eyed Susans are well adapted and hardy in almost every growing zone in the U.S.
If you donít have a separate cutting garden, you can include this plant in a perennial bed or a wildflower meadow. Then, you will have plenty of stems when you need them.
These plants prefer a well drained, slightly acidic to neutral soil. A pH level between 6.0 and 7.0 is considered ideal.
Though black-eyed Susans grow well enough in poor soil, they do best in an average to rich soil. Since they donít like soggy soils, it is best to avoid planting them in poorly drained areas. When caring for these plants, avoid overwatering. Just keep the soil slightly moist.
Depending on the cultivar, these should be spaced from two to three feet apart in the cutting garden.
As with most other kinds of plants in the cutting garden, black-eyed Susans benefit from a yearly application of fertilizer during the growing season. I usually provide this by mulching with compost. However, any general purpose fertilizer, such as 5-10-10, is also satisfactory.
So far as specific kinds of black-eyed Susans are concerned, the ones most commonly used for cutting gardens include the following. Goldsturm Rudbeckia is one of the best. This was chosen as a Perennial of the Year by the Perennial Plant Association. This is a very hardy, freely flowering cultivar. Suited to zones four through nine, this grows to about two feet in height.
Autumn Sun Rudbeckia is quite tall. It reaches four to six feet in height. Suited to zones five through ten, this has strong, sturdy stems.
The black-eyed Susans are pretty much free of most insect and disease problems. If aphids begin appearing on the new growth in the spring, spray them with an insecticidal soap. A spray of water can often accomplish the same results, but this may need to be repeated several times.
In parts of the Deep South where the humidity is extremely high, susceptible varieties of the black-eyed Susans can get mildew on the foliage. This can be prevented by allowing plenty of air circulation between the plants or by growing resistant varieties, such as Goldsturm.
For the cutting garden, the black-eyed Susans can be propagated by several methods, including seed, terminal cuttings, and divisions. For those cultivars or species with runner-like roots, division is the easiest method. If cuttings are used, this is best done in the early to mid-spring.
All species of black-eyed Susans can easily be grown from seed. They will often self-sow. However, most cultivars are best propagated by vegetative means since they donít always come true from seed.