Choosing the right grass under your trees is sometimes more challenging than you think. For example, do you have an oak tree needing new grass under it but don't know where to begin? What grasses don't mind mostly shade and growing near this tree species?
Luckily, we've done plenty of digging and have the answers below!
If you want to plant grass under your oak tree, we recommend fescue (Festuca arundinacea) or zoysia grasses (Zoysia spp). Since these two grass types don't mind shade and do well in rooted soil, they make perfect choices under your oak.
Furthermore, you can expect fescue grass to grow in USDA zones 3-7, while zoysia grasses thrive in zones 5-10. Regardless, the two don't mind being out of the sun.
As we begin this article, we will cover all things planting grass beneath oak trees and show you what varieties are best for this. Whether you're new to growing grass, have a mighty oak tree, or want to learn more about this topic, we're here to help. With that said, let's dive right in!
Can I Plant Grass Under My Oak Tree?
Yes! If you want to add greenery at the base of your oak tree, you can certainly plant grass. However, finding a variety that can handle the conditions your oak produces may be a challenge.
Since most grasses require full sun to grow, planting yours beneath an oak tree can cause trouble. For example, larger oak trees have massive canopies, often blocking the sun from whatever's below.
Unlike having stones or mulch under your tree, growing grass can take time and research. According to Wildflower.org, you want to ensure the canopy of your oak isn't so massive that zero light reaches through.
This might include removing certain branches to make a pathway for sunlight. The key to growing grass below an oak is creating a suitable environment where the two can live harmoniously.
So, if possible, try and find grass that doesn't mind mostly shade, and consider removing some of the branches of your oak. The plants and grass growing below and nearby will appreciate it.
What Types Of Grass Do Best Under Oak Trees?
If you want to plant grass under an oak tree, two main varieties tend to be successful. These are fescue and zoysia grasses, which both don't mind shade.
However, you want to use tall fescue, not fine, as the taller variety does best under an oak tree. Experts explain how fine fescue can't handle southern heat, even under a tree's shade, so aim for taller grass if you're in a warmer USDA zone.
On top of that, California fescue is a great variety to try under your oak tree. Since it handles shade well and doesn't mind growing on top of another root system, this fescue grass is perfect.
Of course, you want to keep these grasses in their preferred USDA zones. Therefore, fescue should stay between zones three and seven, while zoysia grasses need to be between zones five and ten.
Growing grass in the wrong zone can cause it to die during cold or extremely hot weather, so this is crucial. You also want to remember that having grass under a large tree like an oak is already stressful, so try and make the transition as seamless as possible.
Is It Hard To Keep Grass Alive Under An Oak Tree?
Yes, it can be challenging to keep your grass healthy if it's under an oak tree. Typically, grass will experience far less sunlight if it grows beneath an oak tree.
This means your grass will need to work twice as hard to do normal things, like photosynthesis. According to the University of New Hampshire, less light means less photosynthesis and less carbohydrate synthesis.
That, in turn, means not as much food or energy for your grass. On top of that, your grass also needs to compete with the oak tree's roots for water and soil nutrients.
Not only is this unfair to the grass, but it also can lead to patchiness and slowed growth. Comparing an oak tree's roots to a single blade of grass is virtually impossible since oak has a clear advantage.
For this reason, your grass will constantly struggle to get the nutrients it needs to grow and remain green and healthy and may not live quite as long as grass in the sun.
Of course, shade-tolerant grasses like zoysia and fescue can still work: they'll need a bit of TLC.
Do Oak Trees Ruin Grass?
Although we don't think oak trees "ruin" grass, they can definitely put them through a lot. As we mentioned, oak trees tend to have massive canopies that block the sun.
Regularly, that wouldn't be an issue, but it can become one for grass. Since grass requires sun to create energy and grow, having an oak tree block most of it can be deadly.
Therefore, keeping your oak tree in check will mean better grass growing below. Whether that means removing upper branches to let sunlight through or routine pruning, you want to pay close attention to how much light can make its way through your oak.
Another factor that could ruin your grass is the oak tree's root system. Of course, you can't change or alter your tree's roots, so this is up to nature.
If your oak tree starts absorbing all the groundwater and nutrients, this could kill the grass. Therefore, giving your soil extra watering during dry periods is a good idea to prevent competition.
It's virtually impossible for grass to beat an oak tree to water and nutrients, so advocate for both.
Do Oak Leaves Kill Grass?
Another thing to be mindful of with oak trees is their leaves. If you let enough foliage and debris fall from your oak onto the grass below, this can kill it.
Excessive leaves will block the sun from reaching your grass, ultimately killing it. So, you want to try and rake them up as soon as large clusters form.
Of course, a few oak leaves won't harm the grass growing below your tree, but if there's enough: damage can happen. That goes for any plant below your oak, so try and prioritize cleaning and pruning your tree.
According to Melinda Myers, oak leaves are slow to disintegrate, meaning you need to either shred or throw them away. These leaves won't seep into the ground for months at a time, which can be deadly for your grass.
You may even want to shred the oak leaves and use them as an organic supplement to your grass, so don't be afraid to reuse them once collected.
Can Grass Grow In Full Shade?
When it comes to grass being able to grow in the full shade, this won't be easy. Generally, grass needs at least a few hours of sunlight daily to survive.
That means fully shaded conditions will likely kill your grass. However, grass varieties like fescue, zoysia, and ryegrass don't always mind more shade than sunlight, making them great for under or nearby oaks.
Specifically, if you choose to plant zoysia grass below an oak tree, we recommend the Zeon variety. Unlike other warm-season grasses, Zeon zoysia grass will tolerate shade and doesn't mind being out of the sun for extended periods.
In addition, ryegrass and fescue varieties can also tolerate shade, with tall fescue being the best. Remember, finer fescue grass can't handle high heat, even in the shade, so it's not good in higher USDA zones.
Ryegrass is another option, although it isn't always as successful as zoysia and fescue below large canopy trees. The key is finding grass that is comfortable with shade and then seeing if it responds well to being under your oak tree.
Not all grass is the same, so you may need to experiment.
How Many Hours Of Sun Does Grass Need On Average?
Most grasses need around six hours of sunlight each day to grow properly. However, certain varieties require closer to eight, while others may be okay with four.
As we mentioned, oak trees have vast canopies, often blocking natural sunlight. Therefore, your grass may receive mostly ambient light from either side of your tree rather than direct exposure.
This can become problematic if you don't prune the larger branches from your oak, as the grass won't be able to perform photosynthesis. Without food and energy from the sun, the grass is more likely to get sick, thin out, and then die.
Even with shade-tolerant grass varieties, you still can't expect your grass to be okay with no sun exposure. According to TruGreen, grass can tolerate about a 20% filter of sunlight from trees.
That means your grass is okay getting filtered light through an oak's canopy, just not so filtered it doesn't exceed that threshold.
An easy way to help the sun come through your oak is to remove large branches blocking the sun during peak afternoon hours.
We recommend going outside during the heat of the day to see where these branches are and then cut down back at your earliest convenience.
To Finish
Whether you need to add new grass below your oak tree or haven't done this before, it can be hard to create ideal conditions when working around large trees.
From what we found, it is possible to grow grass under an oak tree, as long as you choose a zoysia or fescue variety. Typically, these grasses will handle shade better than others and don't mind growing around an existing tree's root system.
Remember, it is a good idea to cut back the large branches from your oak to let the sun through, so don't be afraid to grab a tree trimmer and get to work!
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