Brian Minter: Rudbeckias have become the go-to plant for a rich golden display

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When long lasting colour is needed for the most challenging hot spots in our gardens, parks or commercial landscapes, there’s one plant family — the rudbeckias — that stands well above the rest.

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Native to the east coast of North America, from Canada to Florida, rudbeckias have become the go-to plant for a rich golden display from early summer into fall. There are over 30 species named by the famous Swedish plantsman, Carolus Linnaeus (1707-1778), to honour his teacher Olof Rudbeck The Younger (1660-1740).

Often known as black-eyed Susans, the Rudbeckia hirta species are more like biennials or short-lived perennials but are mostly sold as annuals at this time of year. Many perennial growers list some larger growing varieties as perennials, and in areas rated zone 7 and higher, they will often come back a second year with a magnificent showing. Recently, however, there are some hardy varieties placed in this species.

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All rudbeckias fit the look and feel of heat-loving summer annuals, and there is a great selection of these beauties, from R. Toto, the shortest variety at 12 inches, to R. Prairie Sun, a giant at 36 inches that produces five-inch blossoms. Their range of rich colours, such as the deep gold of R. Cheyenne Gold and the autumnal shades of R. Cappuccino, a new gold and bronze bicolour introduction, all add vibrancy to our summer gardens. Rudbeckia hirta selections perform well in containers, especially when blended with beautiful fall-toned grasses.

By far, the R. fulgidas are the most well-known of all the rudbeckias. The shining star of this species is R. f. Goldsturm. What’s not to love? This very highly rated variety is hardy to zone 4; is compact, growing in the range of 24 to 36 inches; has rich golden, daisy-like flowers, contrasted by a dark brown cone; is long-flowering, usually opening in late June and blooming well into fall; is heat and drought tolerant; and stands up well in summer rains or windstorms.

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Goldsturm is deservedly the mainstay of many home garden perennial borders and massive park displays.

Ironically, the only problem with Goldsturm is that it is a little overused; consequently, I never plant it alone. For a more naturally beautiful look, I always mix in a few companions, using shorter perennial grasses, like Miscanthus Yaku-jima, or a foreground planting of my new favourite pennisetum, Burgundy Bunny.

There are a few companion perennials which can keep up nicely with this icon. The Sombrero series of echinaceas is one of them. The hot reds, like Salsa Red, vibrant oranges, like Adobe Orange, and bright yellows, like Lemon Yellow, really add a punch of colour. Another is the newly introduced coreopsis ‘Uptick’ series, with its huge blooms and red centres. The Uptick varieties are not only great competitors, but they are also even better companions, playing nicely with Goldsturm well into the fall.

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In Eastern Canada and parts of the U.S. that experience very high humidity, especially in the evening, some Goldsturm plantings have been affected by septoria leaf spot, a fungal disease. A newer variety of rudbeckia, called American Gold Rush, is being used as an alternative because its fine, hairy leaves apparently make it more resistant. A little more compact, it has all the same qualities as Goldsturm.

A few years back at a trade show in Florida, I saw another Goldsturm look-alike, called R. Early Bird Gold. After trialing it, I found it began flowering a few weeks earlier but still performed up to expectations, including lasting well into fall.

One other newer variety that deserves mention is the very disease resistant R. h. Glitters Like Gold. Blooming through October, it is similar in many ways to Goldsturm but with a slightly more rounded habit.

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The true Goldsturm successor, however, is the petite R. Little Goldstar that produces masses of tiny blossoms well into October. It is the go-to rudbeckia where space is an issue. Growing 14 to 16 inches tall, it fits nicely into tiny spaces and containers and is great used in foreground plantings. From Jelitto Seeds in Germany, Little Goldstar is changing where and how rudbeckias can be used in landscapes. It, too, plays nicely with compact grasses and perennials.

From the smallest to the tallest, there’s one rudbeckia that no good-sized garden should be without. It makes a wonderful screen on busy streets and between close neighbours and is ideal used at the back of perennial borders and other flower beds. Rudbeckia laciniata Herbstsonne, growing up to eight feet tall, is a garden standout that is, unfortunately, very seldom used. I love blending it with tall miscanthus grasses, such as Miscanthus Giganteus. The rich dark flowers of eupatorium (Joe Pye weed) also make a perfect mate.

One of the oldest varieties, R. Goldquelle would have been used in our grandmothers’ gardens. A tall (four feet), double flowered variety, it is hardly ever seen in today’s gardens, but, if you can find it, it does make quite a display over a long hot summer.

Because they offer so much versatility in many different garden applications and come in such a wide array of varieties, rudbeckias are summer jewels that deserve a chance to show off their magic.