When visitors see the gardeners planting, they often ask if we replace all our plants each year. One of the many wonderful things about being a perennial garden is that we don't have to re-do our plantings annually. Our plants go dormant in the late fall and start growing again in the spring. However, we do lose plants each year to various kinds of damage. Beetle grubs feed on the roots of many of our grasses and sedges, growing trees and new construction shade out sun-loving plants, and visitors accidentally trample plants as they try to get a particular photo. Because the High Line's structure is a bridge, the plants also experience high winds and more intense cycles of freezing and thawing.
Each fall we assess the damage in the gardens and order new plants for spring. To keep costs and our carbon footprint down, we try to work with local nurseries and order smaller pot sizes or plugs, rather than larger, more established plants. Unfortunately, it can be difficult to source many of our plants locally and in the desired size and quantity. The nursery trade is fickle, with cultivars going in and out of fashion quickly. Even many of our native species can be hard to find.
Additionally, we avoid buying plants that the grower has treated with neonicotinoids, a group of insecticides taken up by the plant's roots. These systemic insecticides persist in the treated plant's tissue, nectar, and pollen for weeks and sometimes months after treatment. Neonicotinoids can harm the very pollinators we want to attract to our gardens. Caterpillars, for example, ingest these insecticides when they bite into a leaf. Butterflies and bees drink them in with nectar. Because bees carry pollen back to their hives, these chemicals can affect an entire colony.
To resolve some of the problems of sourcing plants we have begun to propagate more on the High Line. Traditionally, we have propagated in the gardens by moving seedlings around or dividing and transplanting larger plants. This year, we developed a small nursery operation where we can pot up and nurse along seedlings that might get crowded out if left to fend for themselves in the garden. We are also growing some species from seed. The next Gardening in the Sky post will delve into our seed collecting and propagation techniques. While there are many wonderful, ecologically responsible nurseries in our region from which we will continue to order plants, we are also excited to be growing more of the park's plants ourselves.
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TD Bank is the Presenting Green Sponsor of the High Line.