Mary Ann Ryan
Adams County Master Gardener head honcho

(9/2023) As the summer progresses and fall is just around the corner, our gardens become wild with color and fluttering life, that is if you have black-eyed susans and coreopsis in your garden.

A summer perennial favorite, the black-eyed susan, or the Genus: Rudbeckia, is a colorful group of plants that can play a large role in your summer garden. Not only does the golden color of the flower petals shine, but the activity of birds, butterflies and bees it brings to the garden is well worth a second look. There are many species of rudbeckia that are native to this part of the United States, and therefore, are very hardy and easy to grow.

Rudbeckia fulgida ‘Goldsturm’ was selected as the 1999 perennial plant of the year by the Perennial Plant Association. ‘Goldsturm’ is recognized by its ease of growth, adaptability to soils and heavy blooming. This rudbeckia does well in average to dryer soil conditions, full sun for best blooming, but will tolerate a little shade. It’s a great cut flower and can be used almost as a ground cover and as a mass planting, due to its ability to reseed.

Rudbeckia hirta is considered a biennial but appears to be a perennial because it often will keep coming back – but from seed. This black-eyed susan may also be called a gloriosa daisy. The daisy-like flower is larger than that of the fulgida species, and the flower itself is probably a bit showier due to the size of the flower. But as a mass planting, Rudbeckia fulgida outshines R. hirta. My experience with R. hirta has not been incredibly positive, as it typically doesn’t reseed in my garden. However, I have other gardener friends that have had success.

Rudbeckia maxima, or great coneflower, is an unusual rudbeckia. The foliage is at the base of the plant, reaching about 18 inches. Each leaf can be as long as 12 - 18 inches and they are grey-green in color. The flower stems shoot up to 6 feet in height; and on top of the spike is a yellow flower with a brown center. The petals droop from the center cone, resembling that of a coneflower (Echinacea), but as the flower matures, the center cone elongates as much as five inches. This is a very striking plant when in bloom.

Rudbeckia triloba sports a small daisy flower, about one inch across, on top of a plant that reaches 2 – 3 feet tall. This black-eyed susan is also a biennial, growing a cluster of leaves the first year, flowering the second year, going to seed, and starting all over again. It reseeds very easily and is good for a naturalized area or a meadow as opposed to an area that is more manicured. The seedlings will grow everywhere, making in difficult to contain if you wish to do so. Place this biennial in a location where it can move around.

Another black-eyed susan worth mentioning is Rudbeckia laciniata. Native to the Midwest, not particularly easy to find in the northeast, but a perennial worth searching out. R. laciniata, unlike most rudbeckias, likes moist soils and does particularly well in part sun. Often called Green-headed Coneflower, it is naturally found in moist meadows along wooded areas and floodplain forests in the Midwest, so plant it where there is lots of moisture. It reaches 5 – 7 feet in height and the flowers have the typical yellow rays but they surround a green center. Its leaves are large, about 12" long, and the flowers are about 2 – 3 inches across. It does well in clay soils and blooms late July through early September.

Rough coneflower, Rudbeckia grandiflora, is another tall one, reaching 6’. Native from Ohio to Kansas and south to Texas, this plant grows just fine in our region. It is native to dry, open areas and likes full sun. Although not found natively in PA or MD, this plant can easily adapt to our environment and flourish in our gardens.

An interesting species is Rudbeckia subtomentosa ‘Henry Eilers’. Sometimes blooming as early as June, this is one of the earlier black-eyed susans. It is unique in that the ray flowers are quilled, not flat like others in the genus. Easy to grow, it tolerates most garden soils and enjoys full sun. This one is a true perennial, having rhizomes that allows it to spread. Try this plant in the garden for an extra bit of texture and interest.

Another genus that is popular in the garden is Coreopsis, sometimes called tickseed. There are as many species of this genus as there is of Rudbeckia. Competing for the golden yellow color of the summer, coreopsis is another staple for every garden.

One of the most common plants is Coreopsis verticillata. This plant has almost a feathery foliage, very fine in texture, giving a soft look in the garden. Covered in small yellow flowers, it blooms from June through August one of the longest blooming perennials of the summer. Site this plant in the foreground, as it is on the shorter side – no more than 24 inches. It likes full sun and most garden soils, except wet sites. C. verticillata is parent to many cultivars and varieties, like ‘Moonbeam’ (lemon yellow), ‘Zagreb’ (golden yellow), CrPme Brulee’ (peach). Unlike ‘Moonbeam’ and ‘Zagreb’, my expereinece with CrPme Brulee is that this cultivar is not a particularly reliable perennial. Although quite pretty and unique, I would not bank on this one to continue to come back year after year.

Large-flowered tickseed, Coreopsis grandiflora, is also a very common perennial. Many cultivars have been derived from this species. The foliage may get 12 – 18 inches, then the flowers grow above the foliage another 8 inches on thin stems. Golden yellow, this one blooms for two – three weeks in the summer and is a full sun plant. Coreopsis grandiflora is commonly found in nurseries and garden centers. Native to prairies and open woods, this plant likes it dry. Good for borders in sunny areas. Little problems exist with this tough coreopsis.

One of the tallest of the coreopsis, Coreopsis triperis is a plant on my "to get" list. Yellow daisy-like flowers with brown centers at the top of an eight-foot plant is good for large gardens. This plant does re-seed abundantly, so also great for a meadow planting. It tolerates dry sites and is a pollinator magnet.

Coreopsis auriculata spreads by rhizomes and gets 2 – 3’ tall and full sun. Common cultivars of this species are ‘Jethro Tull’ and ‘Zamphir’, with tubular ray flowers, and ‘Nana’, a compact variety. This genus is quite reliable as a perennial, unlike some of the other species. Adding great summer color, this species is a great addition to the garden.

For me, black-eyed susans and coreopsis are a necessity in the perennial garden. The summer color they contribute is difficult to find in any other native plant. When planning for this yellow –gold color, be prepared for the abundance of plants that will be produced as well as the added bird, bee and butterfly life it will attract.

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