By August, there is a certain tiredness creeping into the garden. The fresh green of May and June has long since faded. Black-eyed Susans, however, are just getting into their summer stride. Standing tall with brilliant yellow, orange and umber flowers, they are among the stars of the August and September border.
Native to large swathes of North America, including the plains and prairies of the Midwest, black-eyed Susans, Rudbeckia hirta spp., are remarkably easy-going plants. Thriving in hot, dry weather, even a modest clump can produce an impressive mass of flowers. I particularly like varieties such as ‘Indian Summer’, with its enormous golden blooms, and ‘Autumn Forest’, whose petals are coloured with shades of bronze and red. Better still, those distinctive dark centres are packed with tiny flowers, providing a valuable late-summer feast for pollinators.
Knowing how to grow black-eyed Susan is relatively straightforward, but a handful of jobs in August can keep the display going well into fall. There are also plenty of unusual varieties beyond the familiar yellow-petalled forms, such as ‘Prairie Glow’, with its warm orange and red tones available from Nature Hills, which can add a little more late-summer interest to pots and borders. Here are four things to do with your black-eyed Susan plants in August.
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1. Watering
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Black-eyed Susans are tough prairie plants, but that doesn’t mean they should be left completely without water during a hot, dry August. Newly planted rudbeckias in particular (ones you have planted this year) will still need a little help while they establish.
Rather than giving plants a light sprinkle every evening, water deeply every few days during prolonged dry weather, directing the water towards the soil around the base of the plant.
Established clumps growing in the ground should require considerably less attention, and I would only step in when the soil is genuinely dry (and cracked). If you are ever unsure, you could also use a water moisture meter, like this from Walmart.
Container-grown plants are different and can dry surprisingly quickly (even in a few hours) in August sunshine, so check these regularly.
2. Deadheading
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Deadheading black-eyed Susans in August is really not essential. Removing the odd brown or faded flower can make your clump look neater, but it won’t suddenly produce masses of new blooms as a result.
For any stems that need a tidy, try these Spear & Jackson pruning shears, available from Target.
I rather like rudbeckias as they begin to fade. The yellow and orange petals gradually lose their brilliance and fall away, leaving those distinctive dark central cones standing through fall.
Those seedheads are mighty useful, too. Once the flowers fade, developing seeds provide food for birds, while the upright stems add structure to borders through fall and winter. For that reason, by late August I would increasingly put the secateurs away. I tend to leave the major tidy until around February or early March, cutting old stems down shortly before fresh spring growth appears.
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These Felco snips are loved by gardeners for their high quality and longevity, ideal for deadheading your perennials.
‘Viette’s Little Suzy’ plants are reliable and compact perennials suitable for any level of gardener, and can be grown down to zone 4.
The Ethical Gardener, by Thomas Rutter, includes tips and advice to future-proof your yard, including native plant advice.
3. Staking
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I find black-eyed Susans pretty good at supporting themselves, but taller varieties can begin to lean and bend, particularly after the heavy rain and strong winds that can arrive in September.
Ideally, I stake taller perennials in early spring, using hazel supports that plants can grow up and through, eventually hiding them almost completely. But if your rudbeckias are beginning to flop now, don’t worry – simply push in a few bamboo canes or hazel rods and loosely secure the stems with garden twine, or, a metal plant support works well, too.
Metal plant supports can be ordered via Amazon.
For open plots, you might consider a compact variety, like ‘Glitters Like Gold’, with live plants available from Nature Hills. This shorter form grows no taller than three feet, and should shrug off fall winds without much concern.
4. Do not feed
(Image credit: Getty Images/ Valdis Veinbergs)
Black-eyed Susans do not generally need much feeding, and in healthy soil they certainly shouldn’t require much fertilizer. By late summer, there is even less reason to reach for the feed in your shed.
Adding a nitrogen-rich fertilizer now can encourage lots of fresh, leafy growth at the expense of flowers, just as plants should be concentrating their energy on the last of the summer display.
Instead, leave your established plants in borders or pots to just get on with it, keeping on top of watering only during prolonged dry spells. If your soil needs improving, a little well-rotted compost or organic matter can be added around plants in the fall. For August, though, put the fertilizer away.
For more seasonal inspiration, check out our guide on what to do with coneflowers in August, with plenty of advice to keep these colourful perennials in good shape.
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