Late-Summer Planting: Perennials to Establish Now
Dear friend,
The sound of cicadas droning in the trees, the heavy scent of warm earth rising after a light rain, the subtle shift in the way shadows stretch across the lawn in the late afternoon—these are the signs I watch for every August. Even as the garden seems to grow quieter, leaning gently toward autumn, I’ve come to think of this time not as a winding down, but as a new beginning.
You see, August is one of the best-kept secrets in the perennial gardener’s calendar. It’s a window of time where the soil is warm, the air begins to cool, and nature offers a golden opportunity: the chance to set roots—literally—for the seasons ahead.
For those of us here in the Blue Ridge Mountains, where ridgelines roll and valleys cradle patches of microclimate, planting perennials in August is a practice that marries timing with intuition. Unlike spring, when soil is often still cold and plants rush headlong into leaf and bloom, late summer offers a quieter energy. A plant tucked into the ground now can settle in gradually, putting energy into its roots instead of racing toward the sun.
I used to think autumn planting meant October. I’d wait for crisp mornings and red maple leaves, thinking I was playing it safe. But over time, I learned the hard way that waiting too long can mean planting into chilled, waterlogged soil—or worse, rushing to beat an early frost. These days, I aim for late summer, ideally 6 to 8 weeks before the first hard freeze, which for us often means mid to late August is prime time.
The soil is still easy to work with. The rains start to return. The roots grow strong and steady. And come spring, those same perennials rise early and with purpose—like they’ve lived here all along.
Why Plant Perennials Now?
The biggest advantage of planting perennials in August is that roots grow more vigorously in warm soil. While the plant's top growth may slow, the underground work is just getting started.
Plant in spring, and you may be watering constantly to keep up with sudden temperature spikes or battling weeds and pests already in high gear. Plant in August, and your new perennials face fewer competitors and milder, settling weather.
Here’s what you get when you plant now:
A stronger root system before winter dormancy
Better resistance to drought next summer
Earlier and more robust spring blooms
Less transplant stress compared to spring-planted perennials
I like to say that August planting gives your plants time to stretch their legs before winter calls them in to rest.
What to Plant in August
Now, let’s talk about the stars of the late-summer planting stage. Whether you’re building a new border, plugging gaps, or replacing a tired annual bed, there are a wealth of hardy, beautiful options that will thank you for a timely planting.
Pollinator Favorites
August is a great time to plant bee balm (Monarda), purple coneflower (Echinacea), and black-eyed Susan (Rudbeckia). These perennials often go on sale late in the season, and while their blooms might be fading in their nursery pots, what matters now is root health.
Plant them in well-prepped soil, water them deeply, and mulch lightly. They’ll redirect their energy into root establishment and reward you next year with a full show of color and pollinator activity.
Ornamental Grasses
This is also a perfect moment to establish warm-season grasses like little bluestem, switchgrass (Panicum virgatum), and prairie dropseed (Sporobolus heterolepis). These plants thrive in full sun and lean soil, and once settled, they’re champions of drought tolerance and low-maintenance structure.
Their seed heads shimmer in the autumn light and stand tall even after a frost. I often pair them with coneflowers and asters for a soft, prairie-style planting that moves like music in the breeze.
Groundcovers and Fillers
If you’ve got patchy areas or newly edged beds, August is also an ideal time to plant groundcovers like:
Creeping phlox (Phlox subulata)
Ajuga (Ajuga reptans)
Wild ginger (Asarum canadense)
Heuchera (Coral bells)
These spread low and slow into the soil while it's still warm, laying down the groundwork for spring’s lush carpet.
Shade-Lovers
In cooler, shadier corners, I’ve had great success planting hostas, ferns, tiarella, and epimedium this time of year. As long as you give them a good drink and some shade while they establish, they’ll root in beautifully and greet spring with vigor.
Division: Giving Old Plants New Life
Late summer is also a perfect time to divide mature perennials. Plants like daylilies, hostas, irises, and yarrow can become crowded over time, flowering less and struggling in the center.
Here’s how I do it:
Choose a cool morning or overcast day
Dig up the entire clump
Use your hands or a garden knife to separate into smaller sections
Trim back any wilted or broken foliage
Replant each division immediately with compost and a good soak
It’s like giving the garden a fresh haircut—invigorating, rejuvenating, and just a little satisfying.
A Few Favorite Combos
If you’re looking to add texture and color, here are a few perennial pairings I love to plant in August:
Coneflower, little bluestem, and mountain mint: A pollinator paradise with gentle movement and vibrant blooms
Black-eyed Susan, switchgrass, and monarda: Bold color and upright structure with long-lasting appeal
Tiarella, hosta, and wild ginger: Perfect for part-shade areas with layered foliage and early spring interest
Keep in mind that all of these need well-prepared soil. I amend each planting hole with a few scoops of compost and make sure the root ball sits at the same level it was in the container. Then I water deeply—no dribbles here. I want the water to reach deep down and encourage the roots to follow.
Watering and Aftercare
Speaking of water: yes, August can still be hot. But that’s no reason to skip planting. You just need to commit to a little regular watering while your new additions establish.
I water deeply every 2–3 days for the first two weeks, unless we get a good soaking rain. After that, I ease back and let the roots do the work. A 2–3 inch layer of shredded bark mulch or leaf mold helps keep the soil cool and moist.
Resist the urge to fertilize right now. It’s tempting, especially when you want to “give them a boost,” but what these plants need is time to root, not to push new top growth. Compost is plenty. Let the soil do its thing.
Planning and Patience
August is also a great time to make those long-intended garden tweaks.
All season, I carry around a battered old notebook with scribbled notes: “Needs more height here.” “Too much bare soil.” “Shade-tolerant groundcover for dry slope.” August is when I begin answering those questions. I walk through the beds in the morning or evening, when the light is kind, and I plant—not frantically, but thoughtfully.
You don’t have to re-landscape your entire yard. Just pick a few spots, a few plant allies, and trust that small steps in August will pay off big come spring.
A Note on the Soul of Planting
Maybe it’s because I’ve been at this a long time, but planting in late summer always makes me feel a little nostalgic. The buzz of spring has quieted. The garden feels fuller, slower, more reflective. And every plant I put in the ground now feels like a commitment—not just to the season ahead, but to next year’s garden.
When spring rolls back around, it’ll look like those plants have always been there.
And when someone visits—maybe a friend, a client, or a neighbor passing by—and they ask, “When did you plant all of this?” I’ll smile and think of these golden August evenings, and the quiet work done with dirt under my fingernails and a hope tucked into each planting hole.
So don’t hang up your spade just yet. If your garden is still speaking to you—asking for fullness, balance, or a little more color—this is your moment. The ground is ready. The plants are willing. And your garden dreams are still very much alive.
With gratitude and a muddy pair of boots,
Logan
P.S. Looking to revamp a perennial border, fill in a shady spot, or plan a pollinator bed for next spring? I’d be glad to help. Visit Unicorn Farm Nursery & Landscaping to schedule a fall planting consultation. Let’s build something beautiful while the soil’s still warm.