Perennial Flower Garden Design – The #1 Mistake

perennial garden

A perennial bed between my vegetable garden and the street adds color and interest to my overall landscape.

When you think about your perennial flower garden design, are you happy with how it looks? 

Do you have continuous color, interesting texture and foliage, and an overall organization of your design?

When looking out your window or sitting in your yard does your garden bring you joy?

As both a vegetable and flower gardener, over the years I’ve designed both kinds of gardens in various yards. And after years of experience, I’ve decided that hands down it’s much harder to create a striking perennial garden than a beautiful vegetable garden.

I’ve redesigned my flower garden multiple times in the past few years – moving and dividing plants, paying attention to bloom times so I know when I have a lull in color, and experimenting with different combinations of plants every year.

It can be a lot of work!

But, over the years I realized I was making one of the most common mistakes of creating a flower garden design – lack of editing!

This realization (and my immediate correction of it!) has resulted in me being able to create a much more beautiful and interesting flower garden.

Unless you’re a professional garden designer, you’re likely making this mistake, too.

In this post, you’ll learn how to avoid a common pitfall when creating a perennial garden and I’ll share some resources to help you craft a flower garden design that more closely matches your vision and delivers lots of impact and color all season long.

flower garden in spring

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Avoid This Mistake in Your Flower Garden Design

We, gardeners, love plants — that’s part of the reason why we garden.

And every spring and summer when we go to the farmers market, garden store, or nursery we often find ourselves buying much more than what was on our list.

It’s easy to become smitten with a showy plant that catches your eye as you walk by.

We see a flower in a particular shade of pink that would fit perfectly into one of our garden beds or we find a new variety of a favorite plant.  We buy one, bring it home, and then try to figure out where to fit it into our garden.

This pattern repeats itself each season, and after a while, we end up with a jumble of plants and a flower garden design with no rhyme or reason and no overall plan. 

Our garden feels crowded, it doesn’t have a rhythm to its blooming color, it doesn’t keep us interested, and it doesn’t sing.

We have become a victim of the onesies!

flower garden in spring

The onesies are when we keep buying one or two different plants every time we go shopping and then end up with only a few of each kind.

This approach often leaves our gardens looking disjointed and messy.

If you take a look at professionally designed gardens around your town you’ll notice that the plants are arranged in blocks and drifts instead of random plants here and there.

This points to a fundamental concept of flower garden design – plants look better and create more visual impact in groups.  A garden of singles and doubles will most likely look cluttered and jumbled.

Tips for Garden Design

One of my favorite flowers for the garden – Allium Purple Sensation

Flower Garden Design Ideas

If you’re looking to elevate your flower garden design, carve out some time to go out into your garden and take a closer look.  Have you planted in drifts and groupings or do you have more of a onesie garden?

If you have more of a onesie garden, here are a few things you can do:

Step #1: Get rid of what’s not working.

It’s time to turn a critical eye to your flower garden design and ruthlessly weed out anything that’s not working. This means plants whose color you don’t like, plants that are too high maintenance, plants that don’t reliably bloom for you, and plants that you don’t overall LOVE!

Dig them up and give them to a friend or place them on the curb for some lucky passerby.

Step #2: Stick to a restricted plant palette.

Step #1 will help you start to narrow down the stars of your garden. These plants should comprise the majority of your design. In this step, it’s important to restrict your plant palette to the high performers and things that give you a lot of bang for your buck – long bloom times, visual impact, great texture or form.

After I realized I was buying too many different plants for my garden I decided it was time to trim down my plant selection and stick to a limited number of plants instead of continually adding more and more new plants.

I told my husband, “When we go to the nursery we can’t buy anything we don’t already have.”

For example, Russian Sage is one of the main plants I use in my garden. When I go to a nursery I can buy other varieties of Russian Sage, but I won’t allow myself to get sucked into purchasing a completely new and random plant that I don’t already have in my gardens.

I have to stick to the main building blocks of my garden design.

flower garden design how to

Step #3: Divide plants.

Now that you’ve started to work on weeding out underperforming plants and honing in on what works best in your garden, it’s time to see if you can divide some plants.

Most perennials grow larger with each season and eventually can be divided into multiple plants. This is great because instead of having to make a trip to the nursery and purchase more plants, you can simply go shopping in your current garden.

Take a look around your garden to see if any of your perennials have grown big enough to be divided.

In general, the best time to divide fall blooming flowers like asters is in the early spring. For spring blooming plants you should wait to divide them until after they’ve bloomed.

Go through your garden and start to divide anything that’s ready for it. You can replant the original plant back into the same place or take this opportunity to move it to a better location.

flower garden design how to

Step #4: Fill in the gaps with newly divided plants.

If you’ve been ruthless in editing your garden like I encouraged you to do in step #1, you should have some gaps in your flower garden design. Use the new divisions to fill in any spaces in your garden.

Try to group the same plant together in blocks or drifts.

For example, if you divide a Russian Sage plant and it’s the only one in that section of your garden, try to plant a few more near it to create a bigger swath so it’s more dramatic.

In professionally designed flower gardens you’ll notice that the plant groupings are often in odd numbers of three, five, seven, nine or more. Try this kind of layout and see how you like it.

how to design a flower garden

Step #5: Now you can buy some plants!

Only after you complete these other steps should you go plant shopping.

If you have some ideas of plants that would fill in your garden design nicely, then go for it! Experimentation, and buying plants, is part of the fun of gardening.

But, this summer when you’re at a nursery (there are great sales in summer!), try to buy some duplicate plants to fill out some of the drifts you’ve started.

As I shared earlier, I often say to myself when browsing at a store, “I can’t buy any plant that I don’t already have somewhere in my landscape.” 

If you do decide to buy a plant you don’t already have, make sure you get at least three, never just one, so you can start with a block of that plant.

Step #5: Observe your garden throughout the season.

Pay close attention to your garden throughout the spring, summer, and fall to see when and where you have gaps in color. I like to snap photos and make notes on them so I can remember what’s planted where, when it blooms, and what sections need more color or texture at a certain time of year.

Over time these observations and notes will help you start to tweak and improve your flower garden design and it will keep getting better each season!

Garden Design Tips

Your vegetable garden in spring can be pretty flat and boring. Why not add a perennial border for some pops of early color?

Designing a Flower Garden: Inspiration

Designing a knockout perennial garden isn’t easy – it takes practice and familiarity with design. I’ve been learning for 15 years and I’m still a better vegetable gardener than flower gardener!

But, if you’d like to spend some time and energy building your skills and improving your garden, here are some of my favorite resources.

Local Gardens: If you live near a botanical or another public garden, try to make a trip there once a month to take a look around. Bring your phone or camera and snap photos of what you like. I’ve found a lot of new plants and interesting combinations this way.

Fellow Home Gardeners: Many cities and towns have gardening clubs that offer regular garden tours. Spend a few days this season being inspired by gardens in your local area.

Check out the Garden Conservancy tours in your town here.

Pinterest: Pinterest is a gardener’s dream! You can use it as a search engine and look for something specific like perennial garden design ideas, or perennial plants for northern climates or for shade gardens.

If you have a Pinterest account start a board of plants you like and want to grow. You can follow mine here.

Books: If you’re like me you might always have a big pile of gardening books next to your favorite reading chair. There are so many good ones out there that sometimes it’s difficult to choose.

The titles below are my four favorite flower garden design books.

Click on the cover for more information.

flower garden design example

Additional Resources for How to Design a Flower Garden

If you’re thinking about building some new areas for flowers learn two easy ways for how to make a flower bed.

In zone 5 where I live, July is usually the height of the flower garden bloom! Read about the tried and true summer-blooming perennials I’ve used in my garden for many years.

Flower bulbs can be an important part of a perennial garden, especially in spring when your other flowers are just starting to emerge. In this post, I share my favorite Colorful & Unusual Bulbs to Plant in Autumn.

Check out my other recommended garden tools, books, seeds, supplies and more in my Amazon storefront.

Come behind the scenes with me for a tour of my vegetable and perennial gardens where I highlight all of the different flowers I grow and how I design them into my garden.


My final piece of advice is to practice, practice, practice! Don’t be afraid to dig up plants, move them around, and try new combinations.

Every year I tweak my flower garden design based on new things I’ve read and learned, because I don’t like some current combinations, or just for the fun of it.

The more you do it the better you’ll get, so dive in and approach your flower gardens with a spirit of experimentation.

Read more about how to create a beautiful garden:




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