How Deep Should a Tree Fern be Planted?

Tree Ferns are gorgeous ornamental plants that look amazing in any garden or home. While they can stay in pots, they much prefer having the freedom to spread out and grow in a garden, where they can be a supporting actor or the star of the show. 

When transferring a Tree Fern, you want to ensure they have enough space, but how deep should you plant a Tree Fern? Generally, a Tree Fern should be planted 2 feet (0.6 m) deep to provide stability for the trunk, as Tree Ferns tend to create wide mats rather than deep roots. 

However, before you plant a Tree Fern in your yard or near your home, we recommend making sure that this tree isn’t invasive in your area. In places like Hawaii, these trees are blacklisted because they spread so quickly and harm other plants in the area. 

How to Plant a Tree Fern?

When planting your Tree Fern, you want to look at doing it in spring. They prefer humid and shady areas, so try to find an ideal place for them. 

About 24 hours before planting your Fern into the garden, ensure your plant is watered thoroughly. You will want to water it until water is draining from the holes in the bottom of your pot. 

When digging a hole, you generally want to make sure to make the hole is two times deeper and wider than the container your plant is in. Mix any fertilizer or soil mixture into the natural soil here while the soil is already loose and dug up. 

Take care to remove the plant from the pot without damaging it. If the container is plastic, it may be easier to cut it open, but be careful not to cut the roots. 

When inserting the tree into the hole, place it in the center so that your plant has equal room on all sides. Hold the Tree Fern up so that it will be in the soil to the same level it was in the pot. You may need to slowly add dirt here so the Fern won’t be too low. 

Finally, once the soil is back in and your plant is stable, you will want to water the plant just a little. Usually, an inch of water (2.5 cm) is enough. Don’t compact the soil more than necessary to keep the plant standing up. 

Do Tree Ferns Need Deep Roots?

Fern root
Tree Ferns have roots, but they aren’t much deeper than you would expect from a plant its size. Instead of going deep, Tree Ferns tend to form a wide mat of roots. This often means that the roots don’t go down more than a couple of inches (about 5 cm). 

However, the roots can grow as wide as 2 to 3 feet (0.6 to 0.9 m). 

Strangely enough, the roots tend to follow the canopy. If you want a shorter plant with less canopy, you can trim it back. People who have done this have noticed that the roots will change so that they don’t grow so much in a mat but then grow down several feet (1 m). 

How Deep Do Tree Fern Roots Go?

Unless you are trying to keep them small, Tree Ferns usually only have roots that grow fairly shallow. When transplanting from a pot to outside, you generally only need to go about 2 feet deep (0.6 m) and about 1 foot across (0.3 m) for your plant to handle the transplant. 

This depth is still not necessarily how deep the roots will go. Instead, it is more to ensure that the tree is stabilized until it can branch out its roots. 

Do Tree Ferns Grow Well in Pots?

Tree ferns can survive for quite a while in pots. Technically, they spend their whole lives in a pot, but they will not do nearly as well as they would in the ground. If you keep them in a pot, try to find one deep and wide to ensure the pot has enough space for the growing roots. 

Though you can easily move them around in pots, remember that Tree Ferns prefer shade and damp spots and don’t do well in direct sunlight or dry areas. 

It is also a good idea to only grow one Tree Fern per pot. The plants will compete and become stressed even if you find a rather large pot. 

Do Tree Ferns Need Deep Soil?

Ferns do not need very deep soil. Even bigger trees only need a hole about 2 feet (0.6 m) deep. This is more for stability than the roots. Smaller trees would probably be fine with about 6 inches (15 cm) for their hole depth. 

Should I Soak Fern Roots Before Planting?

It is a good idea to water Tree Fern roots well before planting. This allows them to adapt better to their transplant and not face too much shock. You can also ensure your plant is watered well for a while after being placed outside, so it has time to grow and establish itself. 

Usually, you can just water Tree Ferns and soak the soil to the point that water comes out of the drainage hole in whatever pot it is in. It is best to do this about 24 hours before planting, although 12 hours is also acceptable. 

What Is the Best Soil for Tree Ferns?

Tree Ferns prefer to have slightly acidic soil. Planting it near pines or in naturally acidic soil is ideal. However, if you don’t have any, you can occasionally mix acidic material like coffee grounds into your soil or water with acidic coffee. 

The soil should also be moist but well-draining. However, as far as soil type, they aren’t picky. They can handle any mixture of sand, loam, and clay. To give your Tree Fern ideal soil conditions, moist, loamy soil is best. 

If you live in a drier area, adding a top layer of mulch onto the soil can provide nutrients and help prevent water evaporation. 

Are Tree Fern Roots Invasive?

Tree Ferns, especially Australian Tree Ferns, are considered very invasive. While they look good in your garden or home, they can cause serious damage to nearby forests if left uncontrolled. 

This is especially true in Hawaii, where Tree Ferns are already starting to out-compete local trees like Hapu’u Ferns. They do so well in these environments for a few reasons. 

The first is that they are good at choking out plants. This means they can effectively remove competition pretty quickly. Since it has a high leaf mass and produces far more fronds than any other plant in the area, it can cover a lot of light and kill surrounding plants. 

The Fern also spreads via spores, and the spores are easily transported via both water and wind. Some tracked spores have been shown to go over 7 miles (12 km) from the original plant. 

In Hawaii, the plant is blacklisted and should never be planted again on the islands. 

However, it isn’t invasive everywhere. In places like the UK, it takes this plant so long to grow that it cannot be considered invasive. In most parts of the United States, it isn’t considered invasive. 

However, if you aren’t sure whether you should plant these trees or not, it is a good idea to ask around and see if someone has them listed as an invasive species in your area. 


Despite growing relatively large and having a large number of fronds, Tree Ferns do not need deep soil. They tend to spread out their roots more than they go down, creating mats of roots right under the surface. 

Generally, a Tree Fern should be planted 2 feet (0.6 m) deep to provide stability for the trunk, as Tree Ferns tend to create wide mats rather than deep roots. Tree Ferns prefer moist, loamy soil but are content with many soil mixtures as long as they are planted in a shady, damp area.

If you want your plant to stay on the smaller side, you must trim it. The trimming process often causes the roots to stop spreading out and instead spread downwards, making them deeper than the average Tree Fern’s roots would usually be.