Plus, now is the time to prep for fall seeding

Last week, we answered these and other questions from students in the delayed final class of Transform Your Yard.​

Dear Avant Gardener, We have an area on the north side of the house that we seeded with smooth penstemon (Penstemon digitalis) and Ohio spiderwort (Tradescantia ohiensis) on a one foot grid three years ago. The bed is approximately 40' by 10'. Since the bed was lodged and looked unkempt and weedy, we cut it to the ground. What do we do now? — K., Wisconsin

First, your bed looks gorgeous! But perennials flopping or lodging — permanently leaning away from the wind or toward the sun — is indeed an issue with our tall and exuberant native plants. Here are several approaches to stop the flop when these perennials grow back next year:

1. Make sure NOT to fertilize. Natives in poor soil will not grow as tall and that’s good.

2. Add structural plants to hold up tall, floppy plants. Many tall perennials evolved in prairies where grasses — as much as 80 percent of prairie vegetation — provide support. Zoe added a matrix of gray’s sedge (Carex grayi) to prop up her monardas; it’s low so it doesn’t interfere visually with the flowers once they grow in. Or you could add a more structural, later flowering perennial like swamp milkweed (Asclepias incarnata), which will also extend the bed’s visual interest. Leaving dead stalks and grasses from the prior year will also provide support.

3. Do the Chelsea chop, cutting back problematic perennials by a third to a half after they have grown — late spring or early summer — but before flowering. You can cut your entire large bed with a string trimmer; in smaller beds, you could cut every other plant to extend the flowering period. The Chelsea chop limits plant height and decreases flopping. Flowers are often smaller but more prolific, because removing the top shoots encourages side shoots to branch out. (Do not do the Chelsea chop on spring bloomers, nor woody plants.)

4. Add external structure around the edge of your bed, like a low hedge or wattle or picket fence. In traditional gardens, low box hedges contain the exuberance of perennial plantings, as well as adding winter interest. In a native garden, you can substitute any of the globular dwarfs of Wisconsin native evergreen shrubs in my article Best Small Native Evergreen Shrubs. Keep in mind that dwarf evergreens are very slow growing, so it’s best to buy them close to the size you need. [For readers along the East Coast, compact cultivars of inkberry holly (Ilex glabra) are a fantastic box replacement.]

5. Adjust your aesthetic expectations.

Yes, that last tip sounds like a cop out. But even I have to remind myself not to be embarrassed by the messier parts of my yard: it's a process, a biodiverse habitat. In England, I was encouraged to see flowers flopping into paths at public gardens tended by professional landscapers. It's a look :)

Because your bed is in a prominent place along your driveway, you will probably want to experiment with one or several of the specific tips above so it brings you joy throughout the growing season. Elsewhere, you may choose to have areas of your yard shine at different times — for example, a woodland garden may look best in early spring, while your penstemon and spiderwort mix dazzles in late spring/early summer. It's all beautiful.

Dear Avant Gardener, Should I chop down in fall or spring or at all? — R., Connecticut

Remember, “Think like an ecosystem?” In nature, perennials die back above ground in the fall and send up new growth in the spring as the old growth decomposes. Meanwhile, the seed heads perennials provide food for birds and hollow stalks provide winter habitat for for bees. And, as Piet Oudolf says, many North American native perennials “look good dead.” The stalks and seedheads add a beautiful winter aesthetic element lost when gardeners “neaten up” in the fall.

In the spring, you can either leave the stalks or prune them once temperatures are reliably in the 50s or higher (but under 90 degrees). This is in mid-April to late May in much of the country. Cut stalks at various heights from 8 to 24 inches, leaving nesting material for bees, as well as architectural support for new growth.

You can either leave cut stalks where they fall, as I do, or chop or compost them to return to your garden sooner or later. (Leaving stalks looks messy, but new growth manages to push through them.) This ensures the nutrients are recycled into the soil.

Dear Avant Gardener, I just moved and now have a large yard that I want to get started on. What can I plant this fall and when should I do it?! — D., New York State

Late summer and early fall is a great time to plant shrubs and trees in most areas of the country. And late fall and early winter is the best time to start many native perennial seeds, which may mean doing prep work before it gets too cold. You can also take advantage of fallen leaves to prepare beds under trees for spring planting; a six to eight inch layer of leaves will be sufficient to kill turf grass.

To give their roots time to establish, plant shrubs and trees at least a month before first frost and water them during that period if you receive less than one inch of rain per week. You can check for the first frost date for your zip at the Farmers Almanac; these dates tend to be conservative, so ask your local native nursery their advice if time is tight.

Dear Avant Gardener, Can you talk about the wisdom (or foolishness) of starting a meadow from seed? — A., New Jersey

Wise! The cost of seeding a meadow is orders of magnitude less than planting plugs or plants, but it requires more patience. A meadow takes several years to mature; plugs give you a six to 12 month head start and plants give you a 12 to 24 months (or more) head start. Keep in mind that it’s not an either/or — you can seed now and then plant plugs and even plants into your meadow next summer.

Late fall or early winter is the best time to seed a meadow, which means starting your prep and ordering seeds now. Here are some tips:

1. Pick an area that gets at least six hours of sun a day. Woodland plants are slower growing and often harder to grow from seed than sun-loving meadow (also called prairie) plants; if you want to try growing woodland plants from seed, try the Wild Seed Project's method, which I describe in Save Money with Winter Sowing.

2. Prepare the ground (see “How” below) and know the limitations of whatever method you choose.

3. Pick a cover crop to protect the soil, minimize weeds, and protect delicate emerging seedlings. Your cover crop can be a fast-growing native grass like Canada wild rye or Virginia wild rye, a sterile exotic hybrid like Regreen, or fast-growing annual or biennial wildflowers. In Zoe’s meadow, black-eyed Susans acted as a cover crop, providing dense vegetation that discouraged weeds. When you seed or plant into existing turf, the turfgrass acts as a cover crop.

4. Consider supplementing an all-native meadow mix with species that grow easily from direct sowing and create drifts of individual species à la Piet Oudolf. (In fact, you can direct sow specific species to create a more traditional perennial garden like K. from Minnesota's, above.)

5. Use several times the recommended amount of seed. Supplier recommendations are based on traditionally prepared soil — i.e., tilled multiple times to remove all existing vegetation and expose, germinate, and kill the existing seed bank. With other methods, fewer of the seeds you sow will germinate, so we have found that direct sowing several times as much seed as recommended works better.

6. Rake the soil lightly to ensure soil-to-seed contact.

7. Mix the seed with a lot of sand — four gallons of slightly moist, clean sand (e.g., sandbox sand from the hardware store) with each 1,000 square feet of seed — and broadcast freehand a section at a time.

8. Cover seeds with a light layer of straw (not hay) to keep them in place and safe from birds and add some organic matter.

9. In the first year, mow the meadow to four to six inches every six weeks or so from spring through fall to stop turf grass and annual weeds from going to seed.

I compared notes with Jesse at Prairie Moon Nursery and we came up with this list of meadow species that are especially easy to grow from direct sowing:

• Wild bergamot (Monarda fistulosa)

• Spotted beebalm (Monarda punctata) — Great as a big patch, flowers first year

• Purple coneflower (Echinacea purpurea)

• Black-eyed susans (Rudbeckia hirta) — Reseeding biennial

• Blue vervain (Verbena hastata) — Work better sprinkled throughout than grouped together

• Anise hyssop (Agastache foeniculum)

• Swamp milkweed (Asclepias incarnata) — Great as a big patch, flowers second year

• Partridge pea (Chamaecrista fasciculata) — Reseeding annual

• Little bluestem (Schizachyrium scoparium) — Grass

• Purple lovegrass (Eragrostis pectinacea) — Grass

Happy planting!

— The Avant Gardener

Why, How, Wow!

Why?

Reading my favorite column this week, I was reminded of the scene in Arlo Guthrie’s epic Vietnam War protest song Alice’s Restaurant when he was sent to a draft board psychiatrist:

And I went up there, I said, "Shrink, I want to kill. I mean, I wanna, I wanna kill. Kill. I wanna, I wanna see, I wanna see blood and gore and guts and veins in my teeth. Eat dead burnt bodies. I mean kill, Kill, KILL, KILL." And I started jumpin up and down yelling, "KILL, KILL, " and he started jumpin up and down with me and we was both jumping up and down yelling, "KILL, KILL." And the sergeant came over, pinned a medal on me, sent me down the hall, said, "You're our boy." — Alice’s Restaurant​

Americans apparently still want to kill — though mostly insects, based on the Washington Post Department of Data’s analysis of Google searches for “how to kill…”

The ongoing insect apocalypse does not seem to have registered with homeowners. Insects — and insectlike entities, since Google searchers aren’t always clear on their taxonomy — are one of the few things Americans want to kill even more than time.
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By our count, bugs make up more than half of the top 100 entities we’re trying to kill. The rankings aren’t precise, as folks sometimes split their vote between multiple phrases, such as “how to kill centipede,” “how to kill a centipede” and “how to kill centipedes.” But for the most part, we were struck by how consistently Americans described their targets. — Washington Post​

Hopefully, dear readers, you now second-guess your own impulses to kill insects. I’ve certainly written extensively, perhaps even mind-numbingly frequently, about the danger of the insect apocalypse to all life on earth. Scary.

But also, like Guthrie’s song, humorous — at least as Department of Data’s Andrew Van Dam reports it. To read his analysis and see some awesome data visualizations about what Americans want to kill and how that differs by state, check out this gift link to Here’s what Americans want to kill, according to Google.​

How

Some potentially good news in the Post’s story is that the plant Americans want to kill the most is grass. That’s often the first step in replacing lawn with native plants to help avert the insect apocalypse. If you’re ready to replace some of your lawn with meadow, direct-sowing native grasses and wildflowers in late fall or early winter is an inexpensive and relatively easy way.

Unfortunately, there’s no silver bullet when it comes to killing grass. Although many ecological landscapers use glyphosate (the primary ingredient in RoundUp), we discourage it; among many reasons, kidney-disease causing glyphosate compounds persist seven years in groundwater and 22 years in soil.

Here are the pros and cons of my personal favorite methods of preparing turf lawns for direct sowing:

• Remove turf with a sod remover or, for small areas, a maddock

  • Best for: Yards with monoculture turf

  • Pros: Fast, neat edges

  • Cons: Disturbs seed bank, can damage tree roots (and cause suckering)

• Solarize turf under clear plastic for six weeks while weather is warm or, if you have time, four weeks on, two weeks off, then four weeks on

  • Best for: Small- to medium-sized areas

  • Pros: Does not disturb seed bank, solarized grass acts as mulch

  • Cons: Plastic waste (and possibly microplastics), kills beneficial soil microbes

• Mowing closely, then dethatching

  • Best for: Large areas

  • Pros: Easy, fast, turf acts as cover crop

  • Cons: Turf and any invasives in it persist until outcompeted by natives, can look messy

Whichever method you use, expect your meadow to evolve over several years, as explained in the chart below from Ben Vogt of Monarch Gardens.​

Wow!

Here’s a recent picture of Zoe’s yard, now in its second season year. The meadow at right was solarized last summer and heavily seeded in the fall with a meadow mix and several additional species. As you can see, she used so much black-eyed Susan (Rudbeckia hirta) seed that this biennial is acting as a glorious cover crop. Although it reseeds, the black-eyed Susans will eventually die out as they are replaced by longer-lasting perennials that establish more slowly. On the left around the circular lawn is a anti-tick border of native mints planted as plugs last summer.

Gorgeous Native Gardens

The most beautiful flower garden in the world is native! That’s right — at least according to TripAdvisor ratings.

Ruth Bancroft Garden in Walnut Creek is Tripadvisor’s highest-rated flower garden, with 62 percent of 5-star 'beautiful' reviews," the [Titan Travel] shared in its findings with Travel + Leisure. "With over 7,400 Instagram posts and a Tripadvisor average review score of 4.5/5, this garden should be at the top of your bucket list. — Travel + Leisure​

The garden's founder was an early proponent of native plants, including them throughout the 3.5-acre garden, alongside other plants from around the world.

Ruth loved California native plants and her fascination with them is reflected throughout the garden and in the large part of the garden dedicated to them. — Ruth Bancroft Garden & Nursery

Encouraging Ecological News

• Researchers at Kansas State University found that soil treated with organic fertilizers stores more carbon.​

• Prescribing experiences in nature can be as effective at treating mental illness as talk therapy or prescription drugs, according to a large U.K. study.

• First-of-its-kind meta-analysis definitively shows that conservation actions are effective at halting and reversing biodiversity loss.