16 Oct

Last of the Late Bloomers

By Chelsea Ruiz

Want your garden to shine just as the leaves start to fall? Learn how timing your cutbacks (and choosing the right set of perennials) can push perennials to bloom later in the season — giving pollinators more to forage and landscapes more to admire!

As you’re looking around in the lingering fall air, you’re making note of what plants are blooming now versus later. Sketching plans of what to do next year, how to improve displays for clients, or new plants for future projects. Whatever the plan, fall is an excellent time to take stock and make plans as the season wraps up before winter.
 
Pro-tip: How to get perennials to bloom later in the season
 
You might make a Scooby-doo noise here of “urrrr!”
 
Why on earth would you want your flowers to bloom later?
 
Well, some designers and maintenance companies may service landscapes where customers return from an annual trip in the fall, rather than in the middle of summer. Others may be returning to work (think of all the public school landscapes as young people return from summer break, as well as the school staff!), or maybe your customer has said in passing that they get sad when they see the leaves changing because it means summer is over. Whatever the reason, having a little ace up the sleeve is always a good tool to use when specific occasions call for it.

Try this maintenance tip for later flowers
 
For established landscapes with mature perennial plant materials, try a midseason cutback of top growth by one-third or one-half. This is an excellent strategy for clients who are not inclined to add new plant material but want to get the most out of what they already have. Trimming back perennial stems earlier in the growing season will delay flowering by several weeks, pushing the bloom window later into the year. Not only this, but a Chelsea Chop (as industry professionals call it) can shorten overall plant heights, helping prevent late-season flop of taller perennials, especially after an intense summer thunderstorm. Another reason is that a cutback encourages smaller flower heads, which avoids late-season sprawl in plants prone to opening up. Need one more justification for doing a cutback in the sweltering sun of midsummer? As the summers and falls stretch into the year, staggering out perennial bloom — mainly through selective midseason cutbacks on clusters of repeating perennials — will provide more forage for wildlife searching for sustenance before the winter season.
 
A midseason cutback works well for specific genera more than others, but what we all learn in gardening is that there is no single right way to do something. It’s always worthwhile to experiment! Here is a short list of perennials we’ve found that respond well to a mid-summer trim:

  • Aster
  • Joe-pye weed
  • Goldenrod
  • Tickseed
  • Sneezeweed 

Even things we don’t list could work…
 
A friend is slowly implementing a new meadow for a client. Part of the first season’s establishment phase and care is infrequent mowing of the meadow to encourage perennial seed germination, root establishment, and to limit competition by other, faster-growing species. The added benefit to this establishment phase is a delayed appearance and show of Rudbeckia triloba! This black-eyed susan patch is a cheery late fall presence in this meadow when all other patches bloomed and set seed weeks ago.

Try planting some harbingers of fall
 
Another way for your landscapes to go even further? Choosing late-blooming plants!
 
Layer in these perennial genera to get a showy display. Some varieties are well-known for either blooming early in the fall season or blooming later, right on the edge of winter (sometimes it's even in the cultivar name!). One of our favorite pro moves is mixing the same plant type with multiple selections, which can reduce visual clutter while also extending the bloom window. An example of this is having more than one kind of aster, or maybe more than one kind of Joe-Pye weed. To the average person, it looks like the same plant. Still, to the garden designer, the genera with multiple varieties begin blooming in July and appear to keep blooming till October. Some of our favorite genera of late-season flowering perennial plants are:
 

A Selective List of Approximate Late Season Bloom Times
Earliest Blooms → Latest
 
Late July
Helianthus ‘Lemon Queen’
Coreopsis tripteris ‘Gold Standard’
Eupatorium maculatum
Eupatorium purpureum ‘Gateway’
Rudbeckia maxima
Rudbeckia laciniata
Helenium ‘Mardi Gras’
Solidago graminifolia
 
August
Ratibida pinnata
Rudbeckia triloba
Rudbeckia fulgida varieties
Rudbeckia subtomentosa ‘Henry Eilers’
Helenium autumnale
Eupatorium fistulosum
Eupatorium dubium ‘Little Joe’
Solidago sphacelata ‘Golden Fleece’
Aster laevis ‘Bluebird’ *(a great candidate to trim back for later bloom time!)

September
 
Coreopsis palustris ‘Summer Sunshine’
Eupatorium coelestinum
Helianthus salicifolius ‘Autumn Gold’
Helianthus salicifolius ‘First Light’ (can be a week or two earlier than Autumn Gold)
Solidago rugosa ‘Fireworks’
Solidago ‘Solar Cascade’
Vernonia lettermannii ‘Iron Butterfly’
Aster ericoides ‘Snow Flurry’
Aster ‘Raydon’s Favorite’
 
October
Vernonia noveboracensis
Aster ‘Purple Dome’
Aster ‘Vibrant Dome’
Aster ‘October Skies’ *(the latest blooming Aster we offer)
Aster lateriflorus ‘Lady in Black’

Disclaimer: take with a grain of salt
 
For a sense of when perennials bloom, we have a rough sketch of bloom order that we have noticed over the years. These observations come with the strongest of disclaimers. It’s hard to pinpoint the exact order which plant varieties bloom when because it depends heavily on an area’s climate, that season’s weather, drought or flooding, altitude, and a host of other factors. Think of this list as broad strokes, less of it written in stone.

Give Fall More Than A Passing Glance
 
We here at North Creek are big fans of autumn. It’s a time to slow down and embrace the changes of the season. Reflecting on past design decisions and taking notes on what could be improved or what new experiments we can cook up. We still have some time to put thoughts into action as the seasons shift. Plants are fully leafed out, and you can see what areas may have holes in the display and what could be improved. Spring always has us cramming in too many new plants and forgetting how big they’ll get, while fall gives us a better understanding of how things are working. Whether you’re thinking about adding more fall beauties into a client’s landscape or contemplating how to make the show you’ve created go on for longer, fall is the perfect time for trying out new ideas.

 

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