Why native plants matter

BY HEATHER MCCARGO

MANY people are hearing the call to plant natives, but there is a lot of confusion about how to do it and why it matters. This article will demonstrate the benefits native plants provide, introduce varieties well suited to Maine landscapes and provide maintenance tips to help ensure a happy, healthy native landscape.

Maine’s native plants are crucial to supporting our local ecosystem, and each of us can have an impact on our region’s biological diversity by how we landscape our properties.

What is “native?”

Native plants are the species of trees, shrubs, vines, wildflowers, grasses and ferns that have grown in our region for millennia. Species that arrived after European settlement – which marks the beginning of a time of great landscape disturbance in North America – are called exotics. Plants grow together in communities determined by soils and sun exposure, and these native habitats are the foundation of a region’s biodiversity.

Ecosystem services

Native plants create the habitats that support the rest of land-based life. These plants have co-evolved with our region’s animals, insects, fungi and soil microorganisms, and many species are mutually dependent on each other – they pollinate plants, disperse seeds and are part the food chain.

The monarch butterfly’s need for milkweed during its caterpillar stage is a well-known example of native species’ co-dependence. A native tree such as the red oak provides food and shelter for hundreds of other species, from insects to birds and small animals.

Native habitats also absorb and store carbon dioxide and precipitation, filter pollutants, decompose dead organisms – thus releasing nutrients – and moderate temperature extremes. Scientist sometimes refer to these helpful attributes as “ecosystem services.”

We have displaced native plant habitats and all the complex relationships they support with paving, buildings, turf and high-maintenance exotic plants. With a rapidly warming climate, it is important that we not lose more native habitat and the ecosystem services they provide.

Sharing space in our yards and developed landscapes with native plants can help stitch together remaining wild habitats, providing corridors for native plants and animals to forage and reproduce, and the pathways to migrate north as the climate warms.

Plant some native species in your yard, and you will immediately see your garden come alive with pollinators and birds. Native plants interact in the landscape in a beautiful and exciting way that exotic plants cannot match.

Native plants are low-maintenance

Many native plants are less demanding to the landscape than common ornamental flowers and food crops. Domesticated plants have been bred with a harvest in mind (or excessive blooms), and many need a lot of water and nutrients to thrive.

With native plantings, soil preparation and maintenance is less resource-intensive. No more importing top soil, large amounts of composts, manures or fertilizers; after the plants are established, no extra irrigation should be needed. Decaying leaves and aged hardwood bark will supply all the nutrients that most native plants require to thrive.

Allowing leaves to remain on planting beds in the fall and planting densely with layers of vegetation (no large patches of mulch between each plant) will mimic the natural processes that protect soils, recycle nutrients and provide overwinter habitat for pollinators.

Native beauty

Maine hosts many beautiful native plants that are easy to grow, and which make resilient garden and landscape plants for every growing condition. For sunny dry sites with gravelly or sandy soil, try introducing butterfly milkweed, sundial lupine and Virginia rose.

Instead of viewing wet ditches and low spots as a problem to be fixed, plant blue iris, swamp milkweed and winterberry holly, all of which are well adapted to fluctuating water levels. For tough shady areas where mulch or hostas are the default, choose from a huge diversity of woodland species such as wild geranium, wood aster and ferns that thrive in these low-light conditions.

Native woody plants are a year-round attraction to people and local fauna alike. Choose from beautiful flowering trees and shrubs that bear spring or summer flowers, colorful fruits and brilliant autumn foliage. While unknown to many gardeners, there are even native species of common garden exotics, including several kinds of rhododendron, spirea and viburnum.

Choose uncultivated forms of natives

While many nurseries in Maine are increasing their offerings of native plants, trends in the modern nursery industry have focused on the mass production of “superior clones.” These cultivars are selected with ornamental traits such as dwarfism, purple or variegated foliage, or altered flower structures such as larger flowers with novel colors or double forms (with multiple petals). These characteristics may be appealing to people, but they often are not to the pollinators and other creatures that have co-evolved with these plants.

In the wild, most plants reproduce by seeds, which develop after the flowers are pollinated by insects. This process mixes the genes of multiple individuals, since a given insect may visit dozens of plants in its foraging, promoting genetic diversity. Individual varieties differ in how they deal with conditions such as heat, drought, excessive rain, cold or pollution.

Genetic diversity is a species’ best strategy for dealing with a changing climate, since it allows for rapid adaptation. Landscapes filled with cloned plants lack this resiliency. As you look to add native species to your landscapes, seek out nurseries that are propagating from seed the natural forms of native plants, not the cultivars.

If each of us offers up some space in our yards to native plants, our urban and suburban landscapes could connect with remaining wild habitat to support pollinators, birds and all the diversity of life that makes Maine such a beautiful state.

For more information on native plants, including photos and growing tips, visit the Wild Seed Project website at wildseedproject.net.

This article first appeared in the spring & summer 2019 issue of Green & Healthy Maine Homes magazine.
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