Designing with Remarkable Plantsmen: Piet Oudolf & Roy Diblik

Over the past six months, I’ve been utterly absorbed in the making of a woodland garden on the edge of our one-acre pond in the rolling hills of Mono, Ontario.

Here is the extraordinary living canvas I have to work with.

Early in the process, I was doubly fortunate to get advice on my plans from two maestros of modern planting design, Piet Oudolf and Roy Diblik.

My last post on this topic introduced them as plantsmen and people. This time, it’s about the design process and how they helped push my ideas forward with some stellar advice and insights.

For gardeners looking to create a sophisticated New Perennial style planting on a relatively smaller scale, I hope these posts can help.

Let me start by introducing the garden space on its own terms – in front of the guest cabin on the far bank of the giant sky mirror, also known as the pond.

Set and setting

In naturalistic design, everything starts with the setting itself.

The more you know about the existing habitat, the more likely your future design and planting decisions will be successful.

Here’s what I’m working with:

Mono Woodland Habitat Profile

• Habitat: Woodland edge and riparian wetland
• Projected Planting Area:  Approx. 120 square metres
• Hardiness Zone: 4b with ample winter snowpack
• Light: Facing east and southeast. Part sun to dappled shade
• Soil: Organic content 7.8
• Moisture: Transitions from dry slope to moist, freely-draining soil and boggy wetland
• PH Level: 7.6 (moderately alkaline)
• Local Wildlife: Insects of all kinds, dragonflies, frogs, birds, bats, ducks, muskrat, porcupine, mink, coyote, and the occasional deer

Preparation is all

The surrounding region is mostly limestone escarpment, which accounts for the alkalinity, a factor which will influence but not necessarily limit plant selection.

Over a period of months last fall, I selectively cleared the area of brush after which, I used a special heavy duty hardpan broadfork used in permaculture, to loosen and aerate the soil without overly disturbing the layers.

Before winter, I brought in a massive 25 yards of Live Mulch from Ontario supplier, GroBark to lay down a 4-inch blanket over the entire planting area to enrich the overall organic content and suppress weed growth in preparation for planting this year.

The KISS maintenance plan

It’s always a good idea to design with maintenance in mind. Here’s my future regime (as per Roy Diblik and Cassian Schmidt):

• Lay down a mulch of chopped-up leaves in the fall
• Cut back the plants in early spring with a mulch-mower or weed wacker
• Leave plants to lie in their own debris to naturally amend the soil

Let the worms and the leaf litter do the rest and try not to disturb the soil food web to allow the microbial life to thrive.

Imaginary gardens with real toads in them

The ultimate creative freedom is to start with a blank slate – tabula rasa. And to think of a theme that can bring it to life.

At the same time, consider the ecological perspective – how the garden and its plant community can fit into and nurture the existing biodiversity.

My plan is to create a wild northern dream garden – a secret and slightly hidden world. From a planting perspective, I want it to be experimental in nature, yet attuned to the rhythms and layers of the greater landscape beyond.

I hope it will provide a sanctuary to lift people out of themselves, myself included.

Dreaming the plant list

It takes years of practical observation to know how different perennials will grow. That’s why the knowledge base of discerning plantsmen  like Piet and Roy, is well worth trusting.

Last winter, I started working up my plant palette by diving into my library of design books and taking copious notes along the way (see my reading list at the end of the post.)

I also reflected on my previous Uncottage garden where I experimented with a more esoteric cast of shade-loving perennials and grasses for a decade and more.

It was there I learned the value of integrating native and exotic woodland perennials to extend the creative and seasonal possibilities of the planting itself.

I poured all this into a dream plant list – breaking it down further into the essential planting layers of primary or structural plants, scatter plants, filler plants, and matrix plants to cover the ground.

Late last year, I’d already lugged over some exquisite and mature woodland plants from my previous un-cottage garden to help kick things off with the new design.

I’ve kept them all in a shady holding bed round the cabin, which has also allowed me to have fun experimenting with various plant combinations.

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Made by hand

It’s all very well to create plant lists. But that’s not what makes a garden.

Like Roy Diblik says, each plant is like a note of music. It may be beautiful on its own but it doesn’t mean anything until it’s combined with other notes to form a melody.

That’s what the design process is all about – using plants to create music in space and time.

From the moment I started to put rough design ideas down on paper, I took a cue from Piet who sketches out his ideas by hand on tracing paper with marker and coloured pencils.

I’m skeptical that a slick software design program can replicate the freedom and subtlety of the hand-drawn approach, especially at the concept stage.

For smaller gardens like my pond project, Piet advises to work on a larger architectural scale (1:50m or even 1:25m for a smaller garden vs. 1:100m) which zooms up the size of the planting.

After much experimentation, these were my first two explorations on paper, which I sent to Piet for review. Please click on the images to magnify – and you can also get a good idea of my plant palette:

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Note that there’s a forked path winding right through the heart of the planting that connects to a longer trail that in the future will circle the pond.

I wanted the planting to be experienced from multiple perspectives and distances – to be readable from both points of entry, from out on the water, from within the planting itself, and out from the windows of the small guest cabin above.

With this in mind, the plans attempt to combine three different forms of planting, which creates interest at the macro and micro levels:

1. Block planting of tall moisture-loving perennials closer to the pond
2. A series of three matrix* plantings running in bands down the slope to the water, each with its own combination of woodland plants set in specific percentages
3. Bog planting with ferns and wetlanders – ideal for plants that like wet feet

* So what is a matrix anyway? 

• The matrix is the ground layer of massed perennials from which, taller, structural plants can emerge
• Comprised of one plant species or several intermingled together in a randomized pattern
• Utilizes ‘quieter’ plants, which offer low-level interest over the entire growing season e.g. grasses, sedges, ferns and low-growing perennials
• Visually unifies the planting
• Keeps weeds down

Piet takes a ‘proper look’

True to his word, Piet took the time to review my initial designs. Within a week, he emailed his comments on a copy of the plan along with visual suggestions on organizing the space.

His first comment: ‘The plants will work well together. I don’t need to discuss your plant choice.”

Yes!

He also advised leaving more clearance room between the taller perennials and the water’s edge.

Smart.

Within the plantings themselves, his advice was to free up the blocks of plants and the matrix patterns, erasing all edges and blending one part into another to create a more spontaneous visual flow and connect diverse sections of the planting.

Super solid advice for any naturalistic planting design.

Big lesson learned?

It’s not just about seeing the bigger picture but knowing how to frame it more effectively as well.

Talking Plants 

He kindly offered the chance to discuss it further via Skype. And so we arranged to hold what ultimately became a 2-hour Skype call to discuss the fine points, as well as more experimental plant choices and perennial strategies.

For example, when using a pair of supersized aggressive perennials like Persicaria polymorpha and Filipendula ‘Rubra Venusta’, Piet advised to place them side by side to keep their growth in check.

Use thugs creatively in your garden. For example, I’m using a summer-blooming Japanese Anemone ‘September Charm’, which I know well from my last garden. Anemones snake out quickly with their roots to cover territory. Take advantage of this quality to unify the planting and simply yank where you don’t want it.

Piet also suggested using taller biennials like Peucedanum verticillare or Digitalis ferruginea to introduce spontaneous patterns into the planting as they seed about over time. I’ll also be using lower-level perennials like Brunnera macrophylla, Aquilegia canadensis, and Spigelia marilandica to achieve the same effect.

On the topic of more unusual plants my pondside habitat, Piet sang the praises of Thalictrum daysocarpum, a North American native that he uses widely at Hummelo and Scutelleria incana, a more refined version of Salvia that works well in part-shade. (Good luck finding these plants at nurseries in Ontario?!)

Revisioning my plan

I took all his advice into account to revise my design plan. To my eye, it’s far more evolved and imaginative. I’ve also listed specific plants that can go into each matrix including ephemerals.

Piet came back with only two comments. Overall, he wrote “Fast learner!” and noted I may want to simplify the matrix but then again, feel free to experiment.

Will do!

Field adjustments with Roy

The next round of advice came from the very grounded Roy Diblik on his visit to Toronto last March.

On the last evening of his three-night stay, we sat down and pored over my revised plans. He read them like a piece of sheet music.

Roy also focused on the importance of linking one area of the planting to another, a quality he picked up from Piet.

For late season interest, Roy recommended adding Asters, especially Eurybia macrophylla ‘Twilight’ – a cultivar, which Piet uses at the Lurie. And he saw the opportunity to introduce drifts of moisture-loving Carex bromoides and Juncus inflexus (Rushes) to fill in the gaps, especially near the water.

His key advice was about making the leap from the plan on paper to the site itself.

At this stage, it’s necessary to make what he calls field adjustments and in a smaller setting like – the easiest way to map out the planting in advance is by using pin flags.

For me, this was incredibly helpful, particularly because I was unlikely to have all the plants ready on site at the same time.

This spring, I ordered a selection of different colour pin flags (cheap at the price) and spent a full two days mapping out the first phase of the planting.

The flags gave me the opportunity to experiment with spacing and placement and to view the planting and patterns from all sides – all before a single plant was put in the ground.

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This way, I could be true to my design plans – while also making adjustments on the fly to make it work in the ground.  I cannot recommend this approach highly enough.

Now I’m into the actual planting phase, and that’s another story again. Thanks again to Piet and Roy for helping me plan my woodland dream.

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