When designing sites, I am often asked to include natural areas so the landscape will be maintenance free. People often equate the word natural with self-sustaining. What is a natural area? Is there really a maintenance free landscape? The visual picture my clients often have of a natural area is quite different from what one would normally see in the wild. They see a golf course in Augusta, GA. They see a heavily mulched grove of pine trees cleanly edged with a free-form barrier between the grass and pine straw. In most instances, they expect any under story plantings to be one thing—hybrid azaleas. Their expectations are that everything inside the boundary between nature and the cultivated landscape will be a grass-less island of carefree trees with a few shrubs tossed in for color.
In the wild the landscape generally has a more layered appearance. Tall pines and hardwoods wear underskirts of smaller flowering trees and evergreens. Wiry stems of Smilax and Brambles entangle themselves into everything. Drifts of amorphous shrub masses reach around the small trees and melt into great and complexly inter-planted sweeps of low shrubs and ground covers. There is something happening and changing at every level. Even though there is a definite break between woods and open meadow, it includes a transitional zone of competing sun and shade loving plants. The ground carpet of wild areas is a tapestry of varying, textured leaf mulches and mosses and tiny plants that somehow manage to give the woodland floor a moist feel, no matter how dry the summer gets. It is wonderful, but it is also messy.
The dynamic quality of the land makes a maintenance-free site an impossible dream. Natural areas are always in the process of becoming something else. The meadow is becoming a piney wood. The pines are changing to hardwoods. Holes are forming on the ground where rotting trees once fell. The ideal of a static high shade woodland is a fantasy. It is only possible in select areas of a climax forest. Lower maintenance and natural beauty are attainable, though, if gardeners simulate the adolescent woodland and make an effort to edit and control the forest dynamics with frequent, preventative grooming. By mimicking the layered, interwoven nature of native settings and by constantly evaluating and editing the different layers, one can work toward a landscape that is simpler to maintain. This can be accompanied by watchful monitoring for problem plants, to prevent weeds from seeding and to discourage encroachment from overly-vigorous plants. Flexibility and change in the maintenance process help make self-sustaining natural areas work.
You can find more information about trees in The Advanced Guide to Trees: Choose Trees like a Pro, part of The Advanced Guide series.
Design should mimic nature in low-maintenance, natural areas. By adding layers of under story trees, evergreen masses, tall shrubs, low shrubs, and ground covers, one can eliminate the top-heavy look of an artificial "natural area" and provide a visual foothold on the surrounding landscape. The sterile nature of a cleared, mulched tree island is lacking in the excitement of contrasting textures, forms, colors, and scale found in nature. By tapering the height down from the center of a natural area to the edges, light is allowed in for all the competing layers of plant material. The eye is carried down to the mass of the island rather than straining through tree trunks to the view beyond. As the edge of a wooded area tapers down in height and the plants approach the edge, more sun tolerant selections can be chosen. That's the way it happens innately.
Properly choosing trees to thin from the area can open up views and eliminate overcrowding. Six to eight feet is a good minimum distance between large trees. Companion, under-story trees can grow happily next to a large tree at even smaller distances. Avoid keeping the trees at fairly uniform distances from each other. It looks much better to maintain a random spacing.
You can beef up the under story and ground plane of a wooded site with plants like the one's listed below or choose your own natives for each category.
UNDER STORY TREES-Redbud, Grancy Greybeard, Carolina Silverbell, Sassafras, American Beech
EVERGREENS-Hemlock, Magnolia, Yaupon, Waxmyrtle, Anise Tree
TALL SHRUBS-Beautyberry, Blueberry, Native Azalea, Winterberry
LOW SHRUBS-Hypericum, Creeping Blueberry, Dwarf Inkberry, Virginia Sweetspire
GROUND COVERS-Christmas Fern, Epimedium, Crossvine, Wild Ginger, Tiarella, Green and Gold
Establish inter-planted ground cover areas to carpet the leaf-litter-laden ground. Never leave the soil bare. By inter planting, a succession of bloom and foliage on the ground plane is possible and a living mulch is created to cover and protect the soil and prevent weeds. Mayapples can be followed by Iris and then Ferns. If you have favorite plant recipe for inter planting, write and let me know about it.
Learn to love the messy aesthetic of a truly natural area. A cleanly trenched edge can give a more controlled look to a natural area, but a better solution would be to have a soft, tapered ground cover extending low fingers into the adjacent lawn. Runaway growth can always be trimmed with the lawn mower. Allow a few volunteer vines to scramble over the shrubs and form interesting lines of decoration. True appreciation of a natural landscape requires a detailed view, so providing stepping stones and seating within a natural area invites people in for an opportunity to enjoy the details.
Including more natural area and less lawn is an excellent idea for easier landscape care. Surrounding your trees in the front lawn with a mulched island is not enough to accomplish this. A complex, layered planting scheme with well-chosen plants can make it beautiful. Careful planning and lots of follow up monitoring of the layered plantings can turn your natural area into a dynamic balance of seasonal change and eco-stability.