Low to the ground or raised high, layers in your landscape give you the opportunity to add more plantings to your garden by taking advantage of each plane level.
The idea of layering dates back to early 20th century gardens, which were tiered, like a church choir, for better viewing. Gardens following this design have plants arranged in three planes—an upper layer at the back of the border with trees and large shrubs, an intermediate layer containing bold grasses and smaller shrubs, and a lower layer of dwarf shrubs and perennials located at the front of the border. This stepped arrangement of heights allows every plant to be fully visible and receive optimal exposure from at least one direction. The strategy works best in a deep planting area using a variety of plant heights and situated adjacent to a lawn. For beds dug in the middle of a lawn, the design can be modified by placing the upper layer in the middle of the bed and then stepping down on all sides, creating a pyramid shape.
Today, layering includes those three-planes plus 2 more, what I’m calling the ground and air planes. Adding more layers with ground covers, annuals, and vines gives a more natural feeling and also allows for a greater variety of plants. Here is a quick look at the planes and some plant possibilities for each.
Upper Plain — Small Trees and Large Shrubs
Choose some trees for height and large shrubs to balance the height of the trees. These can be evergreen or deciduous, open or tightly branched. They will make up just one plane, but each plant in the plane has equal importance. In my border, I grow native dogwoods and redbuds along with big, large-leafed (indica) azaleas.
Intermediate Plain — Small Shrubs, Bold Grasses, Perennials, and Annuals
As the name suggests, the intermediate plane is at about half the height of the upper. This is a choice spot for tall perennials such as purple coneflowers (Echinacea purpurea) and annuals such as cosmos, with varieties growing up to seven feet. Even bulbs can make a welcome addition to the garden—canna, iris, lilies. Grasses are great here too, whether big and bold, like the common pampas grass, or tender and sweet, such as Mexican feather grass (Nassella tenuissima). As with any plant, be sure to check with your county extension agent for invasiveness in your area.
Lower Plain — Perennials, Annuals
The lower plane will offer up a huge variety of both annuals and perennials along with dwarf conifers and shrubs. My spring lower plane is filled with native columbine (Aquilegia), sedums, coreopsis, and hellebores. Summer sizzles up more sedums, phlox, and some of the more interesting varieties of Pericaria amplexicaulis, such as P. amplexicaulis ‘Firetail’.
Ground Plain — Ground Covers
Since I don’t like to see the ground, even though it’s covered with a rich, brown mulch made from composted composted leaves, I would rather see plants. Discovering ground covers has become a great sport for me. I don’t seem to tire of them—dwarf mondo grass (Ophiopogon japonicas); moss (acrocarps and pleurocarps); sedums; veronicas, such as Georgia blue (Veronica peduncularis ‘Georgia Blue’); candytufts (Iberis sempervirens); and even irises, such as the dwarf crested iris (Iris cristata).
Air Plain — Climbers and Vines
Designing with vines is a great way to bring your garden to new heights. Vines also add mood to the landscape—mystery, maturity, opulence, abundance, romance, and adventure. Vines can hide an undesirable, such as a drain spout, or a vine can accent a particular area of your home, such as the porch entrance. A home covered in vines is the epitome of idyllic charm. For these and many more reasons, designing with vines adds interest and style to your home.
Vines climb by a variety of means, and it’s useful to know how they do so in order to buy the best vine for your purpose. Some vines need more help than others to climb.
Vines are grouped either as clingers, twiners, tendrils, or spikers.
Using tiny root hairs, clinging vines attach to surfaces. English ivy, creeping fig, and climbing hydrangea are good examples of clinging vines. If you pull the vine off the wall, it leaves marks from where the rootlets were attached. These vines need no support. They freely climb using their own resources.
These vines use their stems to twine around a structure, such as a trellis, porch post, gazebo, or arbor. These types of vines include wisteria, morning glory, and hops. They wrap their stems around suitable supports and pull themselves up.
Certain vines use either stem or leaf tendrils like little lassos to climb. Looking closely at the vine, you will see that the tendril will either come from the leaf or the stem to grab whatever is handy to pull itself along. Grape vines, clematis, sweet peas, and passionflowers use tendrils to travel.
Spikers spike into something, using their thorns to pull themselves along. Spikers tend to need a little help with support to go where you want them to go. Climbing roses use their thorns to climb. Tying the canes onto a sturdy trellis or wire onto a fence at various locations will help your spiker along.
It’s also perfectly OK to skip a step along the way so everything doesn’t look matchy-matchy. If you follow a formula with tall plants in the back (or middle, depending on the location of the bed and plant sizes gradually getting shorter towards the front, it can look monotonous. Adding occasional tall-ish plants in the front will break up the flow and add interest. Tall, wispy plants work best, as the shorter plants will still be visible through them. Airy grasses like love grass (Eragrostis spectabilis) or spiky plants like verbena-on-a-stick (Verbena bonariensis) are good choices.
When I designed my perennial border, I used many English border design principles, including choosing plants for a layering effect. The English also design to have something in bloom for every month of the growing season. In my case in Raleigh, that’s possible to do even in January. Galanthus, crocus, and certain varieties of daffodils will bloom in January, as will Edgeworthia, flowering apricot (Prunus Mume), witch hazel (Hamamelidaceae), and camellias, to name just a few. The red twig dogwood adds color, and the old flower heads of the hydrangea add interest.
To incorporate more blooms in your garden, work with a designer who is plant savvy and can suggest an array of beautiful plantings to give your garden color year round. Also, as I mentioned in another chapter, visiting local arboreta, garden centers, and friends’ gardens during each season, each month, will show you what’s blooming. It’s a good opportunity to take notes and make purchases.
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