12 Best Plants To Plant Under Your Oak Tree
Grass doesn’t typically grow well under oak trees because it needs full sun and a lot of water. Once oak trees are established, too much water can bring on fungus or root rot. So, here begins our quest to identify some easy going foliage that will grow best under your oak tree.
Plants that are shallow rooted, shade tolerant and don’t need much water can grow well under oak trees. Crocuses, irises, coral bells, hostas, blue-eyed grass, salvia, Canadian wild ginger, yarrow, periwinkle, creeping sedum and phlox are ideally the best plants to grow under your oak tree.
Oak trees are tall, strong, hardwood trees that look great in your yard, parks, or wherever they grow. You would think these mighty trees are nearly invincible, but they have a weakness when it comes to their roots, and you have to be very careful when planting underneath them.
Oak Trees Need Plants That Love Shade
Oak trees are different from most trees as they drink up most of their water needs during wet winters. The cooler temperatures reduce possible harmful fungal issues. During the summer, oak trees like it hot and dry.
Planting grass or other greenery that requires a lot of summer watering or fertilizer under oak trees can spell disaster for the tree. When oak trees get saturated in the summer they can get root rot, crown rot, or Phytophthora, a soil fungus that can be a game ender for these massive trees.
When choosing plants to accompany your oak tree you need to look for foliage that is very drought tolerant. You also need plants that can deal with or love the shade because oak trees often have a dense, sprawling canopy that blocks most sunlight.
You can learn more about how much sunlight and shade oak trees need in general here if you’d like.
Choose Plants That Protect The Oak Tree’s Roots
The root system of oak trees can spread well beyond the canopy, but these roots are also quite shallow. Even the deepest roots of a giant oak tree rarely dig beyond three feet deep. When deciding what and where to plant under your oak tree, you need to be flexible because disturbing the roots can be detrimental.
You shouldn’t even plant anything around the base of the tree. The best practice is actually to not plant anything within the first six to ten feet from the trunk. Using a quality organic mulch around this perimeter is one way to protect the tree’s roots and keep plants from growing in this “no-zone.”
According to The Town of Oakland, Florida, you should avoid heavy landscaping underneath oak trees and select plants that are tolerant of shady and dry conditions. Be sure to plant or irrigate 10 feet away from the trunk of the tree.
When applying mulch around an oak tree, keep it clear three to six inches from the trunk. Only pile it up about two to three inches deep so the ground isn’t compacted, and the roots are able to get air and water.
Oak trees don’t like compacted soil either. Hardscapes and pavers underneath oak trees aren’t recommended because of the way they compact the soil and reduce water absorption.
A single bench underneath the oak tree won’t be too harsh for the tree and may be a great place to sit and read or enjoy the shade from the wide canopy.
Don’t Use Fertilizer
Mature oak trees have a delicate balance of nutrition from the soil and typically don’t need added fertilizer. Adding more nutrients to the soil can adversely affect mature oak trees. They get most of their nutrients through the natural decomposition of leaves and other organic matter.
Mulching is beneficial to oak trees as it allows fallen leaves to create a natural mulch layer underneath the tree.
Plants added to the ground under your oak trees that require a lot of extra feeding could upset the tree’s natural balance.
The best way to feed your oak trees and the plants growing underneath them is to let the leaves naturally decompose. Adding a natural, organic mulch like tree bark is another way to feed your oak without adding chemicals.
For a better explanation of when and how to fertilize oak trees, check out our article on the 3 Best Oak Tree Fertilizers (and How to Use Them) right here!
What Can You Plant Under Oak Trees?
If it’s possible, one way to find out what plants work great under oak trees in your area is to look for wild oak trees. Take a look at these trees and notice what is growing underneath them. The plants and flowers growing wild underneath oak trees will give you an indication of what could work in your yard.
Native plants in your area are already acclimated to the soil, water, and weather conditions and will work best. If they are already growing underneath oak trees, they won’t be competing for water and nutrients.
Another benefit to native plants is that once they are established, they will require no additional care.
Of course, you may not be able to find many wild growing oak trees where you live. That’s okay because we will go over several plants that you can plant under your oak tree.
Use Plants With Shallow Roots
You’ll want to pick plants that are on the smaller side and won’t compete too much with the oak’s roots.
Plants that grow thick, dense roots, or have compact growing habits could reduce water and nutrients to the oak tree. What you are looking for are plants that are able to cohabitate with your tree, and are not competing with it.
One rule of thumb is to look for plants that are in pots no bigger than one gallon. You don’t want to have to dig deep, wide holes that could damage a lot of the tree’s roots.
While you are digging holes for your plants, if you come across clusters of oak roots, you should pick another location.
Don’t Plant High-Maintenance Plants Under Your Oak
You want the oak tree to be the focal point, and your other plants underneath it to be accent plants. Since you shouldn’t plant anything in the soil too close to the trunk, use that area for a nice mulch bed, and then start planting around the drip edge of the tree.
The drip edge of a tree is the area under the canopy where most rainwater starts to drip down through the leaves and branches. Planting large, deep-rooted, and thirsty plants under your oak tree are not recommended, instead, we’ll give you plenty of options that won’t harm the tree.
Now that you know where you can plant under your oak tree, start coming up with a plan and use these plants for that area.
I highly recommend taking a peakski at our piece on the 11 plants NOT to grow under your oak tree so you can learn the difference between what and what not qualifies as a high-maintenance plant.
The Best Plants To Grow Under Your Oak Tree [Full List]
Onto the good stuff! Here’s our full list of the 12 best plants that can thrive under your oak. Let’s get to it.
Crocuses
Hardiness Zones | 3 – 8 |
Bloom Time | Early spring |
Average Size | 4” by 3” |
Water Requirements | Drought tolerant |
Crocuses are early spring blooming perennials that prefer full sun but since they bloom so early, they work great underneath oak trees.
Crocuses will sprout and bloom often before the leaves from most trees have fully leafed out. They are small bulbs that only need to be planted two to three inches in the soil and they don’t make thick, dense clusters.
You can plant small clusters of crocuses around the perimeter of your oak trees for a burst of early spring color that will go back by the time the oak tree has spread its leaves out. Early nectar feeders like honeybees will appreciate crocuses as well.
You can get a start with 10 White Crocus Corms here if you’d like to grow them.
Irises
Hardiness Zones | 4 – 10 |
Bloom Time | Mid spring |
Average Size | 6” by 12” |
Water Requirements | Drought resistant |
These showy flowers grow from rhizomes that look similar to ginger roots found at the grocery store. They can work underneath oak trees, especially at the outer edge, because they don’t compete with oak roots. The rhizomes from irises like to stay in shallow soil.
While most iris species will work, the crested dwarf iris is best suited. This smaller perennial flower prefers partial shade and can be used as ground cover. They bloom in mid spring, offering color after crocuses have already come and gone.
Irises spread through their rhizomes and can be thinned out and moved easily. They are drought tolerant and don’t often need extra watering. Find easy-growing rhizomes right here with these Dwarf Iris Reticulata Flower Bulbs!
Coral Bells
Hardiness Zones | 4 – 9 |
Bloom Time | Late spring to summer |
Average Size | 12” by 24” |
Water Requirements | Drought tolerant |
For some evergreen colors you could plant heucheras or coral bells as some are called. These plants grow from a foot to three feet tall, and about a foot wide. They are mostly known for their bright-colored foliage that typically lasts all year long.
In late spring through the summer coral bells sprout small flower clusters that range in color from white to red. The flower stalk is what gives the trees the height, as the foliage mounds don’t get very tall.
These striking plants work great as border plants. Their foliage can be ruffled around the edges, or variegated. The flowers aren’t as showy as the mounds of leaves but they can attract hummingbirds and butterflies.
Check out this Spearmint Coral Bells Live Plant if you’d like to get started on one!
Hostas
Hardiness Zones | 3 – 9 |
Bloom Time | Summer |
Average Size | Varies |
Water Requirements | Minimal once established |
These perennial plants are a good choice to accompany coral bells as they have similar habits, except hostas don’t stay evergreen. They grow showy, mounding clumps of foliage and in the summer months sprout thin stalks of small flowers.
Hostas are very hardy plants that don’t require much attention once they have become established. It seems the only real requirement for hosts is shade. They don’t tolerate full sun well, but since you’re planting them underneath oak trees, they will do fine there.
You will only need to cut them back when they start turning brown, but other than that, hostas will grow and spread on their own.
Another great thing about hostas is they come in all manner of sizes and colors. You can find green, variegated, white, yellow, blue, and the list goes on. You can find hostas that don’t get very large, all the way up to colossal hostas that can grow up to 60 inches tall!
If you wanted to, you could just plant a plethora of hostas under your oak trees and be done with it. Start off with these Mixed Hosta Perennials (6 Pack of Bare Roots) if you’re going this route.
Blue-Eyed Grass
Hardiness Zones | 4 – 9 |
Bloom Time | Late spring |
Average Size | 24” by 12” |
Water Requirements | Little once established |
This plant isn’t quite a grass, but a mounding perennial flower with more in common with irises. It will grow to a height of about a foot to 20 inches tall and will spread like a ground cover if left to its devices. It grows well in poor, well-drained soil.
Blue-eyed grass will flower from January to early summer. After flowering, it shrivels up and goes dormant through the dry summer months. It’s a small, easy to care for flowering plant that will accentuate the area underneath your oak tree.
If this sounds like something you’d like to plant, you can find live pots with Perennial Farm’s Marketplace Blue-Eyed Grass.
Columbines
Hardiness Zones | 3 – 8 |
Bloom Time | Spring to summer |
Average Size | 1’ to 3’ by 18” |
Water Requirements | Slightly moist soil |
Columbines are another perennial flowering plant that can attract hummingbirds and other pollinators to their exotic looking flowers. These flowers have interesting foliage all growing season long. They will fade away during the winter and then come back next year.
They aren’t very long-lived though, but since they easily reseed themselves, you won’t have much to worry about if you let them keep growing. It takes two years for new columbine plants to flower though, so do get discouraged if they don’t bloom the first season.
These flowers have a little bit higher water need than most other plants on our list, but covering them with a light layer of mulch should do the trick, and keep you from having to water them except in periods of extreme drought.
To keep columbines flowering longer, cut off the drying, old flowers, and they should continue to bloom until the summer heat sets in!
Salvia
Hardiness Zones | 5 – 10 |
Bloom Time | Spring through fall |
Average Size | 1’ to 8’ by 1’ to 3’ |
Water Requirements | Minimal once established |
These plants are also known as sage plants but they are wonderful in the perennial garden and do well underneath your oak trees. They are drought tolerant, pest tolerant, and don’t attract deer or other plant eaters.
Ornamental salvia produces spikes of flower clusters that hummingbirds, butterflies, and bees love to visit. When the flowers start to produce seeds, many bird species will come to feed on them. Salvia typically blooms from summer to autumn.
While most salvia plants prefer full sun, they will still grow well in the partial shade enjoyed underneath large oak trees. They don’t tend to flower as much in shadier areas, but they will still grow well and are a great addition to landscapes underneath oak trees.
You can find live salvia plants here with Perennial Farm’s Marketplace Salvia n. ‘Rose Marvel’.
Canadian Wild Ginger
Hardiness Zones | 3 – 7 |
Bloom Time | Spring to summer |
Average Size | 6” tall, spreads |
Water Requirements | Drought tolerant |
Also known as simply wild ginger, this plant is a good ground cover for shady areas like underneath your oak tree. They only get about four to eight inches tall and spread out relatively easily.
Wild ginger has large heart shaped leaves and small, often hidden flowers that bloom from mid-spring to early summer that attract butterflies. These plants are shade loving, drought tolerant plants that don’t dig deep and will work around your oak trees.
Canadian ginger can be difficult to start from seed and may take a few years to grow, but you can find packs of seeds with these Wild Ginger Seeds AKA Canadian Ginger.
Yarrow
Hardiness Zones | 3 – 9 |
Bloom Time | Summer to fall |
Average Size | 3’ by 3’ |
Water Requirements | Drought tolerant |
These fast-growing perennials can grow from two to four feet tall and have flat clusters of sometimes fragrant flowers that pollinators can’t get enough of. They can come in many colors and do well in poor soil conditions.
In fact, soil that is rich in nutrients can cause the yarrow to grow too tall and spindly. They do well in well-drained soil and can tolerate drought well.
Yarrow will bloom from spring all the way to late fall. These might be the longest blooming flowers on the list, so if you’re looking for colors nearly all year long, get some yarrow. Just remember to deadhead them as the older flowers start to dry out and turn brown.
Yarrows are easy to grow and can be a spreading nuisance if you let them. Once they are established they may have to be cut back or thinned out to keep them under control, but they make great flowers for that dry, nutrient thin area underneath oak trees.
Creeping Sedum
Hardiness Zones | 3 – 10 |
Bloom Time | Summer to fall |
Average Size | 3” tall, spreads out |
Water Requirements | Drought tolerant |
Also known as stonecrop, these nearly indestructible ground covers virtually thrive on neglect and areas where normal plants dare not set root. There are sedum varieties that can grow in every U.S. grow zone. The only thing these plants require is a well-draining soil.
They can’t handle wet, soggy areas, and since oak trees don’t like that kind of soil either, planting creeping sedum underneath oaks will not be a problem.
Creeping sedum does not require supplemental feeding or extra watering. Once they are established, you can pretty much forget about them. They will grow close to the ground and they can crowd out weeds.
The stonecrop plants do tend to prefer full sun, but they will do well in partial shade underneath trees. Their roots are short and don’t dig deep so there’s no fear of sedum competing with oak roots.
Periwinkle
Hardiness Zones | 4 – 9 |
Bloom Time | Spring to summer |
Average Size | 3” to 6” by 18” |
Water Requirements | Drought tolerant |
Also known as vinca minor, periwinkle is an evergreen, spreading ground cover that thrives in shallow soil underneath the shade of tree canopies. They sprout small blue, white, or purplish flowers in the spring and sometimes again in the fall.
The deep emerald shade of leaves is pleasing to look at as they cover ground that grass often can’t handle. Periwinkle spreads by sending out runners that root as they touch the ground.
With their spreading ways, periwinkle are great for erosion control and in shady areas where most other plants don’t do so well. To keep periwinkle contained, just trim them back before they get too established.
To get started with a great, fast-growing ground cover – you can get periwinkle here with these Vinca Minor Ground Cover (50 Mature Bareroot Plants).
Creeping Phlox
Hardiness Zones | 3 -9 |
Bloom Time | Mid to late spring |
Average Size | 5” by 2’ |
Water Requirements | Minimal |
Creeping phlox is another flowering ground cover that works in shady areas and is drought tolerant. In some areas, this phlox is an evergreen or semi-evergreen depending on how cold the winters get.
In the late spring into summer, creeping phlox unleashes a carpet of small, five-petaled flowers that attract all manner of pollinators like moths, honeybees, and butterflies. In the heat of summer, phlox may require some moderate watering to keep it healthy, but since the roots are shallow you won’t have to soak the ground.
They don’t need fertilizer to keep them blooming. As long as you let some of the oak tree’s leaves decompose around them, you’ll have enough organic matter for phlox to feed off of.
You can find this beautiful, flowering ground cover right here from Greenwood Nursery with their Purple Beauty Creeping Phlox.
Say No To English Ivy Near Your Oak Tree
While English ivy can be a great ground cover and it will grow in nearly any soil or light, this plant is incredibly fast-growing and invasive. It is sold in most commercial nurseries but once it’s established, it will take over anything in its way.
English ivy can grow up on trees and starve them out as the ivy drowns out sunlight. It can also climb up houses, get into gutters, and into attics which opens up pathways for all types of insect pests.
It’s also very difficult to get rid of English ivy once it starts growing. The roots can grow deep, and often have to be dug up to remove all the ivy. The stems are easily cultivated so care has to be taken to keep them from growing back.
You can learn more about that in our guide on what you should do if you have vines on your oak!
Add Shade Loving Plants In Containers Near Your Oak Tree
To give the area under an oak tree some added vertical visuals you can add shade-loving plants in containers. You can plant shrubs, small trees, or flowers that require more fertilizer and water than is comfortable for oak trees in the containers.
Just use light containers instead of cement and stone containers that will end up compacting the soil underneath them. Another way to lighten the containers is to cover the bottom with something like empty plastic bottles, cut pool noodles, or other lightweight filler.
To solve the problem of water draining out of the bottom of the containers, plant succulents or other plants to absorb the runoff so it doesn’t soak the oak tree roots.
The Best Time To Plant Under Your Oak
Fall, or better yet, late fall is the best time to plant under your oak trees. It’s around this time and during winter when oak trees absorb most of the moisture they need for the year.
This time is also beneficial to the plants because it gives them time to get roots established for next year.
During the dry summer months, oak trees prefer to stay dry, and constant watering of new plants can cause fungal problems in them.
Plant Together When They Are Young
If it’s at all possible, plant oak trees and the plants you want underneath them together. Young oak trees are much more forgiving to environmental changes than older, established trees. It’s not unlike that grumpy grandpa we all know who can’t stand any kind of change to his routine.
You should still add mulch around the tree a few feet wide—be sure it’s not touching the trunk—so that the roots aren’t disturbed. As the tree trunk expands over the years, move the mulch bed out, and move the plants around it to compensate.
Watering Needs For New Plants Underneath Your Oak Tree
New plants need extra watering when they are planted, but you’re trying not to water too much underneath the oak tree because that can be detrimental. What do you do? You can still water new plants as long as you focus on the plants themselves.
Don’t use drip hoses or sprinklers. They will add way too much water to the oak tree which could be an issue.
You’ll have to water your new plants the old fashioned way by either bringing a hose out and only watering the plants themselves or use a watering can.
Another word of advice here is to water infrequently. Most of the plants on this list are drought tolerant and will handle dry periods, so you don’t have to water them every day. It’s best to give them light drinks of water every couple of days in the beginning and during times of extended droughts.
You should be careful when you are watering oaks, as it may promote the growth of moss. For more information, read our article about what to do if you find moss on your oak trees!
Wrapping Up!
To best accentuate the sensitive area underneath oak trees you should seek out native plants if at all possible that are tolerant of shade and dry conditions. Be sure you don’t disturb the oak tree’s roots or water it too much because doing so can be detrimental to the tree.
Using a natural mulch and leaving the leaves underneath the tree at least ten feet from the trunk is a good way to protect the roots. Then plant drought tolerant, shade accepting plants to bring out the natural beauty of your oak tree.
References
Grünwald, Niklaus J., et al. “Emergence of the sudden oak death pathogen Phytophthora ramorum.” Trends in microbiology 20.3 (2012): 131-138.
Pages, Loic. “Growth patterns of the lateral roots of young oak (Quercus robur) tree seedlings Relationship with apical diameter.” New Phytologist 130.4 (1995): 503-509.
Bridge, M. C., and V. Winchester. “An evaluation of standard oak tree growth in Ruislip woods, West London.” Botanical Journal of the Linnean Society 134.1-2 (2000): 61-71.
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