Please note: At the time this blog was written, construction was estimated to be completed in June. Weather conditions during the Spring season have delayed the reopening. Due to the weather dependency of the remaining work, the Lily Pool remains closed to allow for the final stages of the rebuild to be undertaken with the same meticulousness as work already completed. Stay in touch with the Conservancy for continuing updates as work advances and check out our events calendar for limited opportunities to visit the Pool as construction continues.
Reconstruction on Alfred Caldwell’s historic pavilion is nearing completion. Work is ongoing, but also heavily impacted by weather. Given favorable conditions, the Pool will reopen in tandem with its namesake waterlilies in June.
As the reopening of the Lily Pool approaches, this installment of our blog series summarizes the restoration work going on in the garden. Read more about our successes and ongoing efforts below and stay tuned for more details on the reopening of this historic wonder of Lincoln Park.
Invasive Tree Removals
Many invasive trees, slated for removal a quarter century ago, were instead left standing due to the high cost of dismantling them without causing collateral damage to hardscape, fencing, and desirable plants. As part of the Conservancy’s recommitment to the site and commemoration of 25 years of stewarding the Lily Pool, we are prioritizing the deferred removal of these increasingly problematic trees to allow intended plants to thrive.
The primary problem these trees cause is oppressive shade along with extremely dry, root-laden soil— conditions that prevent the establishment of understory plants that would enrich the landscape. These problem trees stymie others while also offering severely limited aesthetic value in themselves— they have poor form, unremarkable Fall color, and are prone to unsightly foliar diseases, like tar spot. Tar spot, though not deadly, is fatal to the attractiveness of a maple, and has become more common in the Chicago area in recent years. Norway maples are particularly susceptible to infection and exhibit especially severe symptoms.
On the topic of leaves, while leaving them in place is generally beneficial, it can be detrimental in the case of invasive trees. Excessive leaf litter smothers the understory, depriving the groundcover plants of sunlight, causing rot, and negatively altering soil chemistry. In the Lily Pool, these leaves can cause additional problems for the Pool itself, that ultimately necessitate costly and intrusive dredging.
Finally, the reason so many of these trees are here is due to their tremendous reproductive abilities— they grow fast and generate hundreds of saplings each year. The necessity to quickly remove these rapid growers throughout the fragile garden occupies limited staff time that could otherwise be spent on enhancing rather than defending the space.
Woody Plant Rejuvenation
The prolonged presence of mature invasive trees caused the disfigurement of many ornamental trees and shrubs long-suffering under the dense shade. In most cases, rehabilitation of these individuals is a multi-year process, as it takes time for them to grow to balance out their form, and the necessary corrective pruning must be done over several seasons to limit stress on the tree or shrub.
Other shrubs, like elderberry, grow remarkably fast but are prone to dieback, leaving thickets of dead, brittle stems without the intervention of regular rejuvenation pruning. In years past, budget constraints and competing priorities resulted in passive management throughout the site that left views blocked and overgrown. The implementation of an active winter pruning regimen in 2022 has not only resulted in healthier elderberries and other woody plants, but also in restored vistas.
Understory Overhaul
To halt erosion of an overused site, especially one with steep slopes, netting overseeded with aggressive grasses are a common, budget-friendly tactic with lasting consequences. Erosion is slowed, but the original landscape plan gets sacrificed to the quick fix as more delicate plants are outcompeted and struggle to spread. As we take a new approach to site management, netting and aggressive grasses are being systematically removed to allow violets, geraniums, and other surviving herbaceous plants to spread. We are also adding plants each season to repopulate barren areas, add diversity and thereby increase resilience, and, when possible, to reintroduce sensitive species that have been lost.
Rate of Inflow Determined
The inflow throttle controls have been broken for several years. The inability to control the flow resulted in repeated flooding that damaged the entry path and the pavilion. With the need to resolve the flooding in tandem with the pavilion restoration, determining the proper rate of flow became paramount. After a number of consultations, archival research, and some trial and error, we were able to understand the inflow and drainage system well enough to craft a solution. Last year, we were able to collaborate with the Park District’s plumbers to throttle the flow from the main line and achieve the trickle Caldwell intended. Repairs to the throttle controls are upcoming.
Power Restored to the Lantern
For years, the discreet, integrated lantern just east of the entry gates sat dark, but for the past year, it has been a beacon of the ongoing work happening inside. The extended closure allowed for exploratory electric work inside the entrance to restore the connection to the lantern, left out of the original build but custom-fabricated based on Caldwell’s drawings as part of the Conservancy’s original restoration of the site in 2001. Enjoy the subtle light and know we’re continually striving to create a Lily Pool that honors Alfred Caldwell’s vision.
