The Waiting Canopy
Spring projects are in full swing! Plants in the ground, mulch down, visions coming to life. But what about those tricky early years when young trees haven’t yet cast their shade? How do you design a planting that works now and in the future?
Troubleshooting what to plant while trees establish
There’s nothing quite as exciting as breaking ground for a new project in spring. Clearing the land, eyes roaming a clean slate, and dreaming up endless possibilities. All winter long, we’re contemplating new plant combinations and possible solutions to landscape challenges, just waiting for this moment to prove our mettle in planting season. Well, we’re in it now, and our plant material is getting in the ground. Trees and shrubs planted, herbaceous material installed, and mulch applied—check, check, and check. However…
A recent problem we were thinking about was the conundrum of the early establishment years - what do we do in the interim when we have young trees that eventually have full canopies, and the client wants the planting bed completed this season? Realistically, the conditions during the early establishment phase will be completely different than later years as the tree fills out and shades its roots. Shade plants that go in now will fry in the full sun, while full sun plants will struggle and die out once the tree canopy matures. How do we plan that planting design? How do we square that circle?
Well, using nature as our inspiration, there are two routes:
Multi-phase plan
Some projects fully embrace the idea that landscape design is a process and not just a one-time event. The client is excited by the space's gradual development and loves the concept of replicating the stages of natural growth, albeit in miniature and on a faster time scale. For these projects, we propose a multi-phase plan.
In the first phase, when the space is cleared and a young shade tree is planted, lay out the planting beds as if the herbaceous plant materials were pioneer species first arriving on newly opened ground. Choose short-lived, full sun species that give bursts of seasonal color and instant impact within the first growing season. Bonus points are awarded if there is a mix of plants that can boost the soil health: deep taproots to break up soil layers, nitrogen fixers, or species with many fibrous shallow roots to add organic material. Landscape Plugs™ are a mindful choice for this approach, not only offering better savings for the client per plant unit by buying material in bulk, which helps the project stay on budget to complete Phase Two later, but also decreases natural resource demand (Landscape Plug™ trays use less plastic, less soil, and require less transportation fuel per unit compared to larger plant sizes).
Taking cues from nature, select pioneer species for this transitional space. They establish quickly within the first season and typically spread around the bed, adding spontaneity to the planting design. They will persist in the design until the tree canopy grows, and then, the bed will be planted for the next phase with a shade planting. Here are some of our favorite fast-growing native plants that will settle in and provide seasonal color:
Tickseed
Coneflower
Brown-eyed susan
Upright prairie coneflower
Common milkweed
Beardtongue
Blue mist flower
Purple lovegrass
False chamomile
Wild pinks
Pussytoes
Wild petunia
Allium
Wine cups
Broomsedge
Sideoats grama
Blazing star
Adaptable plants for then and now
Just as the previous route took a cue from nature, this option also employs a different plant community as inspiration and a guiding light. For projects that are budget-conscious and have time constraints, where multiple project phases are not an option, plant selections that tolerate higher sun exposure during the early years and can eventually tolerate more shade as the tree cover matures are a good option. Generally, plants that originate from woodland edge environments are best able to accept the transition from full sun exposure to increasing shade. However, the sun tolerance range greatly depends on the light intensity, based on the project location and soil conditions. Full sun and dry soil can lead to plant failure for plants that prefer shade. Some shade plants tolerate full sun in the upper North, such as in Michigan or Maine, but will struggle lower in the Mid-Atlantic to the South, so beware pushing a plant past its limits in your location. Supplemental irrigation during dry periods can help a plant tolerate greater sun exposure while the tree is growing. Still, it's important not to overwater the tree while trying to support herbaceous plant material. Conversely, some perennials especially enjoy the increase in light levels and will have greater floral display when positioned in a planting bed with new trees, such as the Aster and Solidago species. Here are some of our woodland edge transitional plant recommendations:
Heuchera ‘Autumn Bride’
blue wood aster
White wood aster
Northern sea oats
Tufted hairgrass
Blue-eyed grass
Ragwort
Turtlehead
Cardinal flower
Bluestem goldenrod
Zigzag goldenrod
Wild columbine
Anemone
Fleabane
A Fork in the Road
It’s a complex problem to conceptualize and plan for a space that you understand will change dramatically in a relatively short period. While 5-10 years sounds like a long time when looking at a calendar, it’s a blink of an eye for a landscape. However, nothing is new under the sun, and while staring at a freshly-mulched young tree bed, we realized the answer to the exposed site problem was right in front of us. Utilizing habitats that specialize in change, whether a significant change like a forest being cleared, or a gradual, inching change like the spread of a forest’s edge, there’s a plant community that already has it covered. The key is to observe and reflect on what potential solution best fits the needs of the site, the project, and the client. Nature never ceases to amaze us, and just when you think you’re dealing with a particularly modern problem, you realize there is an ancient solution. Go figure.
