Perennial gardens underneath trees can be a beautiful addition to your landscape–but it can be tricky to grow plants underneath them in a way that supports both the growth of the tree and your new perennials. In this post, we’ll chat about some of the pitfalls to avoid when creating your flower garden under a tree, and some strategies for keeping all plants happy.
Just a quick disclaimer, I’m gardening in zone 3 in Saskatoon, Saskatchewan, Canada, so all of the plants I mention are native to me and my zone. If you live in zones 2-5, chances are you can plant much of the same things. If you live in zone 6+, you might be able to plant what I mention, and if not you likely have a lot more options available to you.
Not all Trees Are Good Candidates
While it would be nice to plant a garden under any tree you like, not all trees are good candidates. Walnut trees are more difficult to plant under, as they release a chemical called juglone, that negatively affects a lot of plants. The area under coniferous trees is often acidic, which means fewer plants can make their homes there.
Deciduous trees in general are easier to create a landscape under, as they have more light available for spring blooming perennials (since their leaves may not have budded yet), and they have a more dappled shade underneath them.
Create a Landscape Under a Newer Tree
The easiest way to create a perennial garden underneath a tree, is to make it when the tree in question is still young. That way, you don’t run into the roots of a more established tree, and the plants you plant have a chance to establish their roots better.
Remember to keep your plants & mulch away from the tree trunk!
Beware Invasive Perennials
Unfortunately, a lot of the perennials that are good candidates for growing underneath a tree, tend to also be invasive. Not all perennials are invasive in every location–it depends on your climate and soil type. The best way to check if the perennial you want to plant will create future problems, is to google [your location] + “invasive perennials.”
While some people are totally willing to do the work of managing invasive perennials year after year and keeping them in the intended spot, the future home owners of your property may not. And while invasive perennials do have benefits to them, like providing food for pollinators, you have to weigh that out between the threat they can pose to the environment. Read the comments of this post to gain a further understanding of what can happen when plants go wild.
Leave a Healthy Amount of Space Between the Tree and the Perennial Garden
To avoid killing the roots of the tree, and creating endless frustration for yourself trying to grow plants that never take, don’t plant anything within 3 feet of the tree trunk. The more established the tree, the farther out you may need to plant. If you’re constantly hitting roots as you dig, you need to move farther away from the tree.
You can also fix this problem by adding a layer of soil to plant in on top of the existing soil. However, you’ll still want to keep away a minimum of 3 feet from the tree trunk. If you surround the trunk with extra soil and mulch, you actually risk killing the tree. Sure, it looks good, but is it worth killing a much-loved tree?
The Same Rules of Good Perennial Flower Bed Design Apply
Think of designing a flower garden with perennials like arranging kids in a class picture–tall kids at the back, short kids at the front. In terms of plants, this means that ground cover like verbena and rock foil will live at the edges of the perennial garden, and any bushes or taller plants will live nearer the tree.
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What Plants Grow Well Underneath a Tree?
So glad you asked! In general, look for plants that do well in part shade to full shade. If you’re planting under a coniferous tree, also look for plants that tolerate acidic soil. If you need help finding ideas, here’s 32 plants that grow well under trees, all of which will work in zone 3!
When All Else Fails, Create a Container Garden
I know, I know. . . that’s not what you had planned. But hear me out. If everything is struggling and nothing will grow, you can still get the same look and feel by creating a garden with shade-loving plants in containers of different heights and colours. Then, surround the area with mulch so you don’t have to worry about as many weeds.
We did this in our front yard recently because nothing, not even grass, was growing under the tree that neighbours our yard and it just looked terrible. Instead, we covered the area with mulch, made a seating area, and potted up a bunch of begonias, impatiens, and coleus in pots of a variety of sizes. Now instead of being the sad-looking yard on the block, it’s an attractive space that you actually want to hang out in.
The tree brings much needed shade so we can visit friends and neighbours without sweating buckets, and having everything in containers means there’s next to no weeding and we can take everything with us if we move.
Want to Create a Perennial Garden that Constantly Blooms from Spring to Fall, without Constant Work? Here’s how. . .
The Constant Colour Garden is the easiest way to create a perennial garden that always has something blooming. With 5 done for you plans, 5 templates, and an easy system to follow, you’ll be creating a beautiful perennial garden in no time!