Three Principle of Perennial Garden Design

A very wide border separated by fence and access pathway
When it comes to perennial garden design, we have several questions that need answering.

1. 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.  A third option is to grow the single plant for a few years and then propagate it yourself

Massive display of Hellebore and Daffodils

2. 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.

A mix of annuals, perennials and foliage plants

3. 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.

You can read other practical landscaping tips right here

4 thoughts on “Three Principle of Perennial Garden Design”

  1. The hardest part is the waiting!! I have a front flower bed that is 20″ long and approximately 12′ wide at it’s widest part. I have been working on this bed for almost 5 years now and it is starting to look good, but keeping on a budget makes it a slower process. I am a fan of shopping the “end of season” perennial sales and nursing the plants back to health. This has saved me a lot of money over the years, but again, you have to wait for their beauty to shine!! I do agree with you that the hardy annuals really help the bed look more finished. They fill up the holes, my favorite are zinnia and marigold for the hardy annuals. I also like to add begonias here and there to add color.
    P.S. Pre-planning is a really good idea as I learned the hard way! Have had to dig up and move several plants that I didn’t plant in the right place initially and ended up not having enough sunlight.

  2. Bigger may indeed be better, but what if you don’t have a vast property and unlimited wealth? Why can’t small gardens work?

  3. I view gardening as a fun journey that never ends. It’s take time and patience but the reward is worth it. Many times I buy one perennial or other plants and propagate or divide it once it gets larger. I have not only expanded my gardens but also my friends at very little or no cost. I also teach my friends how to do this so I can also get perennials from their yard. 🙂
    I also keep my purchased plant containers and reuse them to start new plants, and have an area where I let many of my cuttings grow until it’s time to move them to their permanent home. I find in Upstate SC, the best time to start new plants is in the Fall. By Spring they are ready for their new homes!
    Gardening is like decorating. Sometimes you have to move plants around for the best effect or due to sun, soil and moisture conditions.; or just need to dig them up and divide them. I am always amazed at how well and fast they grown with they have great soil and moisture conditions.
    I live in an area that has soil with 20% clay, 20% sand, and 60% silt. What that means is that the soil does not drain well and has few nutrients. I keep a pile of pine fines and compost on hand and incorporate this into every planting area to improve drainage and nutrients for my plants to thrive. This also helps to elevate the beds for drainage. It takes time to amend the soil, but it pays off and makes installing new plants much more fun. You will also start getting lots of earth worms that also aerate the soil! I have always found that takes 99% of my time to create a new home for plants and very little time to plant, That’s when gardening becomes a lot of fun!

  4. Small gardens do indeed work but they take a different approach. The traditional perennial border isn’t something that’s going to find an effective home in a small garden.

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