This article by Plant to Pick columnist Debbie Lonnee appeared in the July/August 2019 issue of Northern Gardener.
Since 1990, the Perennial Plant Association, a group of professional perennial growers, designers, retailers and educators, has promoted a “Plant of the Year.” These plants are chosen because they are low-maintenance, have multiple seasons of ornamental interest, are suitable for a wide range of climatic conditions, and are relatively pest- and disease-free.
In 1999, the association chose Rudbeckia fulgida ‘Goldsturm’ as Plant of the Year, and this German-bred seed strain became one of the most popular and widely grown perennials in northern gardens. I’d place a bet that at least 90 percent of Northern Gardener readers have this popular variety in their gardens.
Unfortunately, over the years, a disease called septoria leaf spot has attacked ‘Goldsturm’, and it has become a problem not only in gardens but at the nurseries that produce this variety. One other little problem that has bugged me the last few years is that ‘Goldsturm’ is a heavy seeder; you can spend plenty of time weeding out the seedlings that have germinated in your garden beds.
A Better Rudbeckia
Just in time, Chicago-area breeder Brent Horvath, from Intrinsic Perennials, has bred and introduced a new Rudbeckia cultivar called ‘American Gold Rush’. You may look at the photo and wonder what’s different.
First and foremost, this cultivar has excellent resistance to septoria leaf spot. That one point should motivate you to remove all of your ‘Goldsturm’ and move to this disease-free variety.
But it is a lovely plant as well. It is an interspecific cross and you may notice the foliage is different from ‘Goldsturm’. It is longer, thinner and hairier, which helps keep the disease off of the plant. Overall, it is a slightly more compact variety, reaching a mature height in the range of 22 to 26 inches. It will spread ultimately to 24 to 36 inches, although some East Coast gardeners are seeing it spread to almost 40 inches in width. It has a very nice rounded, neat habit.
Black-eyed Susan has always been a mainstay of the late summer and autumn garden for its colorful gold foliage with dark eyes. It will start to bloom in late July and will be in color through September. It is great in combination with Russian sage (Perovskia), fall asters and ornamental grasses. Those flowers will attract all sorts of pollinators into your garden, including bees, butterflies and songbirds.
Plant ‘American Gold Rush’ in full-sun gardens with well-drained soils. Once established, it will easily handle drought. If you take the time to deadhead the early flowers, you may extend the flowering season well into October. This plant is vegetatively propagated and has a patent, so propagation is prohibited. While listed as hardy to only USDA Zone 4, I suspect that is just because it has not been thoroughly tested for winter hardiness in zone 3. Those of you in the North may want to give this one a try.
Horticulturist Debbie Lonnee works in the horticulture industry and gardens in South St. Paul.