More Is Better
It is impossible to have too many perennials in your garden. The pictures we all drool over rarely consist of single plants. When you look at them closely, you will see that huge mass of blooms is not coming from a single plant but rather from several plants of the same kind planted together.
The first general planting rule is that a minimum of three plants of any kind is always planted together to create a color mass.
After a few seasons of growth, the flowering mass will grow together to create the special effect we see in magazines. It is not that you cannot grow such lush plants as the gardeners in the pictures, it is that you do not plant enough of the plants together to create that effect.
As a frugal gardener, I do know the best plants are often the most expensive and planting three of them can do serious damage to the budget. You have the option of planting one and allowing it to grow and spread. Or you can do as I do–pretend that it is a garden emergency and the costs will only happen “just this once.”
Creating that perfect flowering picture demands using the correct number of plants; any reduction in numbers will reduce the effect and the magic.
Bigger Is Better
I tried to sugarcoat this in several ways but it always came back to this main point: bigger is better. There is no way around it; perennial gardens look better when they are larger. Herbaceous perennials do not look good in small beds. Alpine plants look good in small gardens; but then again, alpines are small plants.
It is a question of proportion and the proportion that beginning designers should remember is 3:1. For every three feet of length of the garden bed, the width should be one foot.
This means that a short ten foot bed has to be at least 3 1/2 feet wide (let us not quibble over an inch or two) to be in proportion. A backyard garden of 20 feet in length along the back of the property should then be at least six to seven feet wide. Beds can be made wider than the formula would suggest but they are only made narrower at the designer’s peril.
The maximum width for longer borders in many of the classic designs seems to vary between 14 and 20 feet. If the flower bed stretches past 45 feet in length, it is not necessary to widen the bed past 14 feet. It is possible, but not absolutely necessary.
Wide Gardens Give You a Front and a Back
Wide gardens have the needed space to give a “front” as well as a “back” to the bed. It is this front and back that give the garden designer the ability to create a season-long blooming garden. Without this needed space, it will be almost impossible to create a good display.
Narrow garden spaces that cannot be enlarged are perfect homes for single-season gardens or single-plant gardens. A very narrow shaded space, along a property line in a city lot, for example, would be a perfect spot for a fern garden or a hosta garden. One of the nicer narrow gardens I have seen was a hosta garden with only stepping stones between the plants along the dark shady section between two homes.
If the garden has room for a “back,” it allows the gardener to create, using tall perennials or hedges, a backdrop against which to show off the flowers in the front of the border. Examine the magazine or book photographs again. Most of the wonderful shots show the flowers against a dark background of some kind. Following the 3:1 ratio of length to width creates the space for these backgrounds.
Annuals aren’t better, they’re just necessary.
This bit of advice is sometimes considered heresy in the perennial garden world. Use annuals sparingly to create consistent and on-going color patches. Gertrude Jekyl, the doyenne of the British cottage gardening style, used annuals. If they were good enough for her, how can I suggest otherwise?
In my own gardens, I use hardy annuals to give a splash of color to tide the garden over dull periods. Hardy annuals are annuals that are either sown in the garden in the spring, such as asters and zinnia, or self-sow around themselves from year to year.
In my garden, self-sowing Verbena bonariensis is almost a bit of a pest and has to be weeded out every spring. It is allowed to grow here and there in the garden beds because it brings hints of mauve/purple to the fall garden. This contrasts nicely with the preponderance of yellows and oranges that are more commonly found at this time of year.
Ruthless Weeding
Friends use cosmos in this way and over a few years have managed to create a custom color scheme by only allowing the blooming plants of their choice to set seeds.
All plants that are not of the desired color are weeded out as soon as their buds begin to show color. In this way, the surviving plants set seed and in subsequent growing seasons, their offspring are more likely to have the desired color effect. After a few years, this weeding out of unwanted colors is reduced considerably.
On a fashion conscious note, I rarely see half-hardy annuals–the ones that you purchase as started plants in spring garden centers–used in the perennial bed. This is not to say that petunias, geraniums, and marigolds and the like should not be used if you so desire. It is, after all, your garden.
What you will likely find after a few years of experimentation is that the half-hardy annuals never quite fit into your garden scheme. They tend to be strongly colored and clash with the gentler-toned perennials. You’ll also discover that after a few years of gardening success, your expanding perennials and self-sown hardy annuals will not give you much extra room to install these greenhouse softies.