Can I Install Artificial Grass Under Oak Trees? (Pros & Cons)
Natural grass lawns and oak trees are both beautiful additions to a home’s landscaping, but installing these features close to each other is not a great idea. Having grass around its base is bad for the oak tree, and having an oak tree nearby is bad for the grass. This means that installing natural grass and oaks too close together results in no one being happy.
In most cases, the oak tree will win out and the grass will die or, at minimum, fail to thrive in the oak tree’s shadow. In some cases, the reverse can happen and the natural grass will do enough damage to weaken or kill the oak. Both oak trees and natural grass lawns are significant investments, so neither of these situations is ideal.
Therefore, if you have oak trees — or are planning on planting some — and you also want a lawn, you need to consider your options. Let’s start by taking a look at why oak trees and natural grass do not play well together.
Natural Grass and Oak Trees
There are lots of reasons why it is not a good idea to install a natural grass lawn under oak trees. Here are four examples that show why folks who want both oak trees and grass should consider artificial grass installation instead.
1. Oak trees produce a lot of tannins.
As oak tree leaves, twigs, and acorns decompose, they add tannins to the soil. This makes the soil more acidic, which is fine for the oak tree but is detrimental to the health of many types of plants and grasses. This means that natural grass will have a harder time surviving in the acidic soil under an oak.
2. Natural grass and oak trees will compete for nutrients.
Most things that you plant in close proximity are going to compete with each other for the nutrients in the soil. In the case of oaks and grass, oak tree root systems are large and expansive, which means they usually succeed in taking most of the nutrients for themselves. This is, of course, not great for the health and longevity of your natural lawn. In some cases, the shallower roots of the grass can grab most of the nitrogen before it can reach the roots of the oak, which then robs the oak of this necessary nutrient.
3. Established oak trees do not require a lot of water but natural grass does.
We have talked a lot about planting in zones to group together plants with similar irrigation needs. This helps conserve water and helps to ensure that each plant is getting as little or as much water as it needs to thrive. Established oak trees and natural grass lawns have vastly different irrigation needs. If you water only as much as the oak needs, your grass will quickly die. If you water the area according to how much water your grass needs, the oak tree root systems are going to absorb more of their fair share of water and leave your lawn thirsty. At the same time, this can rot the root system of the oak and cause irreparable damage or a dangerous situation where a top-heavy tree loses a large branch over your home, patio, or driveway.
4. Oak trees are shady characters.
Oak trees provide a lot of shade. This is great for protecting play areas or outdoor living areas from the sun, but it is not at all good for a natural grass lawn, since most types of grass require plenty of sunlight to thrive.
Alternatives to Natural Grass Under Oak Trees
Since it is clear that conventional grass does not do well under oak trees, anyone who has oak trees or who plans to install them needs to look at alternative ground covers.
While it might seem like a hardscape, such as a patio, might be a good option, it is not. Non-breathable hardscapes, such as concrete, bricks, or flagstones are not good choices for installation around any type of tree trunk, including oak trees. Ideally, this type of hardscape should be outside of the dripline of the tree. Anything closer will crowd the roots, hinder water absorption, and rob the roots of oxygen.
Plus, the damage goes both ways on this one: While patios can damage the trees, the trees can also damage the patios. Root growth can crack concrete slabs and dislodge mortared brick or flagstone installations. If you go with pavers, the sand is going to allow for some more root growth, and the way the pavers zip together will allow you to unzip them and put them back together if root growth is enough to make them shift. So paving stone patios are a better choice than poured or mortared options.
A better option for a patio-like feature is a deck. Made from wood or composite, a deck built off the ground allows for root growth, water absorption, and oxygen getting into the soil and into the roots. A deck may still see damage over time from root growth affecting the posts and, if you are not careful, you could injure the oak tree root system when installing your deck.
Other oak-friendly ground covers are wood chips, bark, mulch, or gravel. This type of ground cover does not compete with nearby trees for nutrients, does not require water, and allows water to permeate into the soil for the trees to absorb.
However, if what you really want is a grass lawn, none of these options are going to work for you. Gravel, wood chips, or a patio are not going to give you the look, feel, or function of a grass lawn. If this is what you are going for, a better option is going to be an artificial grass installation.
Synthetic turf lawns look, feel, and function like natural grass lawns. They provide a level surface where pets and kids can play, stay green and welcoming every month of the year and in drought conditions, require much less maintenance than natural lawns, and can be installed where natural grass will not grow or cannot grow well.
Can I Install Artificial Grass Under Oak Trees?
Now that we have gone over some of the options and know that artificial grass is the only ground cover that is going to give you the look and function of a lawn, let’s look more closely at whether or not it is a good idea to install artificial grass around trees.
The most common concerns about installing synthetic grass under trees are whether or not it will harm the tree’s roots, whether or not the tree roots will damage the fake turf as they grow, and whether or not it will be difficult to properly install artificial grass in this situation.
Artificial Grass Around Trees: Pros
1. You can fertilize trees with artificial grass around them.
If you are considering an artificial grass installation, you may be concerned that you will not be able to fertilize your trees. The first thing to know about this is that an established oak tree does not need fertilizer, so this is not an issue. If you install fake grass around other types of trees that do require fertilizer, you can fertilize them on top of the synthetic grass and allow water to take the fertilizer through the permeable backing and into the soil.
If you plan to do this, first talk to your artificial grass installer so that they can help you better understand which fertilizers will work well for this application process and which could clog the backing material or damage your lawn.
2. Artificial grass does not require excessive irrigation.
Choosing synthetic turf over natural grass is an easy way to save water, since natural grass lawns require thousands of gallons of water every year and artificial grass only requires spraying it down every once in a while with a garden hose to remove dust and debris or to rinse down pet restroom areas.
Therefore, unlike natural grass, artificial turf does not pose a danger to tree roots in regards to excessive water in the soil. Because fake grass is permeable, the rainfall or irrigation that provides water to the tree’s root system will permeate through the porous backing and into the soil where the roots can absorb it.
3. Artificial grass is more functional than natural grass.
Manufactured lawns provide a level, even surface for seating areas, play areas, and outdoor dining rooms. Unlike natural grass, synthetic grass can also be enjoyed right after rain with no concerns about mud or tracking wet blades of grass into the house. It is also easier to keep clean, which means less bacterial buildup that could make a natural grass lawn a less-than-ideal place to hang out or have your children playing. These characteristics make artificial grass more functional than natural grass and allow you to enjoy your lawn more often and with fewer concerns.
4. Artificial grass requires less maintenance.
The most obvious benefit of choosing lower-maintenance landscaping options is that you can spend less time caring for your yard and more time enjoying it. But when it comes to artificial grass around trees, there are added benefits. For example, natural lawns require aerating, but aerating could damage oak tree root systems, so choosing an option that does not require this type of maintenance helps both you and your trees.
Artificial grass also requires no pesticides, fertilizers, or herbicides, which means you do not have to expose your family or your trees to unnecessary chemicals.
Artificial Grass Around Trees: Cons
1. There is a possibility that tree roots can make artificial grass sag or shift.
One common question when considering an artificial grass installation around oak trees is whether or not the oak tree roots will damage the synthetic grass or cause it to shift as the roots near the surface grow. While it is possible for surface-level oak tree roots to grow in a manner that could make your artificial grass shift or sag in that area over a long period of time, this can be easily fixed. Plus, this is not a common occurrence, and it would take a long time for the tree’s roots to grow enough to cause a noticeable difference.
If this does occur, simply call your installer to come out and fix it.
2. Base preparation for artificial grass is different when installing under trees.
Another common concern with installing artificial grass under oak trees is whether or not you can properly prepare the base beneath the turf. There are several steps involved in properly installing artificial grass, and base preparation is integral to the overall integrity of your lawn. When a project calls for installing artificial grass under oak trees, the main concern is avoiding damaging the roots of a wanted tree. For example, surface-level tree roots will influence the amount of soil compaction you can achieve without causing damage to the roots.
While installing artificial grass under oak trees is different than installing it away from these large root systems, this does not prohibit the use of synthetic turf in these situations. Experienced turf installers will be able to successfully install your grass and make any necessary recommendations to ensure a satisfactory end result.
3. Some trees may be affected by the heat absorption of artificial grass.
Artificial grass does absorb heat differently than natural grass, which can be an issue for some species of trees. However, fake turf mostly increases in temperature when exposed to direct sunlight on very hot days, and the temperature of the grass quickly drops when shade is introduced.
Oak trees provide large canopies of shade that would cover much of the grass laid over the root system, which would help to regulate the temperature of the grass. Additionally, the oak trees that thrive in Southern California are well-suited for thriving in hot, dry conditions. And, of course, artificial grass under oak trees can help insulate the roots of trees during the colder months of winter.
How to Install Oak Trees
In most cases, experienced gardeners and landscape designers recommend installing ornamental plants and trees as transplants rather than growing them from seed. This allows you to benefit from the immediate gratification of a partially grown tree, as well as the increased chance of survival that comes with plants and trees that are already past the seedling stage. You will not have to wait as long for your trees to grow to maturity and your landscaping will have a more finished look sooner.
This is not the case with oak trees. You can transplant an oak tree. People do it all the time. It costs thousands of dollars to buy one, it takes a lot of work to transplant it, and there is a good chance the tree will die, since oak trees do not transplant well.
If you are planning to install an oak tree you purchase from a grower, you can expect it to be up to about eight feet tall. This is about how tall they can get before the severe root pruning required to transplant them will more than likely kill them.
Site prep includes picking a sunny spot with plenty of space to accommodate a mature oak tree. This means a spot with space for the canopy as well as root growth, so you should not plant an oak tree anywhere near a patio, walkway, driveway, street, or building foundation.
Dig a hole that is a little larger than the root ball and have this ready before the tree is delivered. Oak tree transplants need to be installed immediately, so make sure your site is ready before your tree arrives.
Once the tree is in the ground, you will need to water it once or twice a week for several months. You will also want to protect your investment by staking the tree to keep it straight and to protect it from wind while the root system becomes established; Additionally, you will need to protect it from animals with tree guards or a wire cage placed around the trunk.
If you choose to install a transplanted oak, you will get to enjoy the look of your tree sooner; however, the growth will not be the same as if it was planted on your property. Therefore, if you transplanted an oak tree from a grower and planted the same variety of oak tree from an acorn or a small seedling, the tree planted on your property will ultimately grow faster and better than the transplanted oak.
Instead of spending thousands of dollars on an oak tree that may not survive being transplanted, you also have the option of growing an oak tree from an acorn for free. To do this, collect acorns from the variety of oak tree you would like to plant. Place them in a bowl of water and discard any acorns that float.
Plant your acorn about one-half inch deep in a sunny spot where there is enough space for the tree’s canopy and root system. It is best to do this in December or January. Water regularly until established and protect your acorns and seedlings from rodents by using a tree guard or a wire basket.
Keep in mind that oak trees grow very slowly, which means you will wait many years before you see your tree develop into a large, canopied tree. This is true whether you plant an acorn or transplant an older tree.