The Forgotten Layer – Shrubs

It’s easy to forget to plant shrubs. Many homeowners associate native plants with perennials, and this is quite understandable. Open a gardening magazine, or an issue of Birds and Blooms, and you are besieged with images of beautiful native flowers adorned with bumblebees busily pollinating, or goldfinches pecking away at seeds. Many homeowners, me included, began their native plant journeys with perennials, as they are easy to grow and delight us year after year.

Following perennials, homeowners oftentimes look to add or replace trees. Sometimes, they are dissatisfied with the trees supplied by developers on their properties. Sometimes they are looking for “specimen” trees (trees that draw attention because of their beauty or form)—to replace trees that are old, for shade, or to fill in large open spaces. As gardeners continue on their journey into the “native plant world,” they become familiar with nurseries where they can obtain native plants, and they may just wander over to the tree sections and start to inspect the specimens there. Trees are a dramatic addition to the homeowner’s garden.

Many homeowners stop there. They have beautiful flower gardens and magnificent trees, yet they may notice that something is missing, particularly if they are trying to create a diverse habitat for wildlife. They look up, and they look down, unaware that an entire middle layer of plants is missing, and this is sometimes referred to as the forgotten layer – shrubs.

All diverse habitats have one thing in common—layers—and if homeowners wish to duplicate a natural world, they need to consider the middle layer and add shrubs. This layer is the link between the herbaceous layer of flowers and the higher layer of trees. Shrubs can create lines of sight, adding artistic definition to the garden and providing additional habitat for birds. If you want to increase the diversity of birds on your property you need to include native shrubs. In addition to nesting space, shrubs offer birds food (berry-bearing shrubs) and protection from predators.

One particularly attractive feature is known as a “biohedge,” which is a mix of native shrubs with varied flowering and fruiting habits, grouped together. Biohedges can be created along driveways, serve as privacy fences, or serve as a backdrop for herbaceous perennials. Biohedges can be designed to have year-round interest. Shrubs can be selected to produce flowers during the spring and summer, seed pods in the later summer or fall, and berries during various seasons. Herbaceous plants can be mixed in to provide additional interest.

The biohedges in the photos above border a driveway. The shrubs that are part of these hedges include:

• Aronia melanocarpa -Low Scape Mound ® Chokeberry. This shrub is a dwarf cultivar of the native. It blooms in the spring, produces dark berries in the summer, has brilliant red foliage in the fall, and is very tolerant to many conditions. It is deciduous.
• Rhus aromatica – Fragrant Sumac. This is a small-to-medium size shrub with very aromatic foliage. It blooms in the spring and is also a host plant for the Spring Azure and Red-Banded Hairstreak butterflies. It’s frequently used as a groundcover. It is deciduous.
• Clethra alinifolia aka Sweet Pepperbush. There are many cultivars of this shrub with very fragrant sprigs of flowers that bloom in mid-summer. Pollinators of all types are attracted to this shrub, and it will give you years of fragrant joy. It is deciduous.
• Cephalanthus Sugar Shack® Dwarf Buttonbush. This cultivar has very attractive glossy foliage and the most interesting flowers that bloom in mid-summer. They too are pollinator magnets and provide an interesting texture to the hedge. It can be aggressive so will likely need pruning. It is deciduous.
• Cornus serecia – Arctic Fire®Red Dogwood. This is a dwarf cultivar and displays brilliant red stems during the winter months. It is deciduous.
• Tortuga® Juniperus communis. This evergreen shrub has a very compact habitat and is a very tolerant plant. It also adds interest in the winter when it turns a bronze color.
• Rudebeckia hirta – Black-eyed Susans were perennials added for interest and color.

Like all native plants, shrubs tend to be robust and resistant to pests and diseases. There is little need for fertilizers, and provided that you plant them in the right conditions (e.g. moist soil areas or drier areas, depending on the species), they will be virtually maintenance free. Be sure to consider spacing such that your shrubs can comfortably grow to their full size. Depending on where they are planted, pruning may or may not be required, yet it is always a good practice to remove dead branches to maintain the plant’s health. Mulching too, with natural mulches—such as shredded leaves, aged wood chips, etc. or undyed wood mulch—is good practice.

Shrubs will add so much to your landscape and increase the potential for biodiversity on your property, so be sure to consider them.

Click here for more information and examples of shrubs native to PA.

Barbara Beck, Richland Township Bird Town Leader, provided the text and images for this article.