Rubber Trees (Ficus elastica) are versatile plants that grow rapidly, making them perfect for filling spaces in the home. One downside to fast-growing plants, however, is they tend to outgrow their pots quicker than we’d like and have a tendency to get rootbound if we aren’t paying attention. Is being rootbound bad for a Rubber Tree?
Generally, when a plant gets rootbound, its health begins to suffer and growth slows or stops. It is also harder to care for a rootbound Rubber Tree as keeping the soil correctly watered becomes more difficult. While they’ll tolerate being rootbound to some extent, they will only thrive in an appropriately sized container.
There is a lot of talk about whether or not you should let your plants get rootbound and if there are benefits to this practice. I tend to fall in the camp of always providing your plant with adequate space to grow, mainly because I want my plants to stay as healthy as possible. Below, I’ll outline what it means to be rootbound and how to repot your Rubber Tree when the time comes.
What Does it Mean to Be “Rootbound”?
As your houseplants grow, not only are they putting growth out above the soil, but they are also expanding their root systems to maximize water and nutrient absorption.
Because they are planted in pots, over time, their roots run up against the walls of the container and continue snaking around, looking for more space. Eventually, you end up with a root ball that can be densely wrapped around itself.
If you remove the plant from its pot, the root ball will often slide out of it (although you may need to give it a hard tug) and keep the pot’s shape. You can easily see how the roots have circled around multiple times, forming a dense mat.
Because Rubber Trees are fast-growing plants, they tend to be more susceptible to getting rootbound. Within a couple of seasons, you may notice that you are having to water more often or that the plant’s growth has slowed significantly. These may be signs that your Rubber Tree is rootbound.
Rubber Trees in the Wild
When considering if a Rubber Tree houseplant “likes” being rootbound, it might be helpful to look back to its ancestors for clues on how Rubber Trees grow in their natural environments.
Wild Rubber Trees are native to South and Southeast Asia and have been naturalized in many other places around the world. In their natural habitats, they can grow up to 100 feet tall. For trees of that height they do have a rather impressive root structure.
Rubber Trees utilize the growth of buttressing roots (thick, shallow roots that act as support structures) and aerial roots (roots that grow in the air, not in soil, and grab onto rocks and other trees for support) to support their towering heights, rather than growing deep roots to hold the tree in the ground.
Those structures free up the tree to focus on growing a vast, sprawling network of shallow roots that stay near the surface of the forest floor, where most water and nutrients can be found. Shallow roots maximize a Rubber Tree’s ability to utilize these resources and allow the plant to thrive. If the root structures aren’t allowed to sprawl, the tree becomes limited in how fast it can grow.
Rubber Trees Indoors
The Rubber Trees we keep inside our homes have been cultivated from their wild relatives to be somewhat tamer and more manageable. Typically, indoor Rubber Tree plants tend to top out in height between six to eight feet.
However, they are still very much like their native cousins. They can grow aerial roots, and if you’ve kept a Rubber Tree for enough years, you may have noticed the trunk beginning to flange, which is a sign of it developing buttressing roots for support.
So, it is not surprising to learn that Rubber Tree roots like to spread out. Often times, they will find the edges of a container quite quickly (within a growing season or two), and if they aren’t potted up to a larger size, the next time you do repot, you’ll notice the crowded roots circling around the root ball.
Now, this isn’t a serious cause for concern since Rubber Trees handle being rootbound just fine for a while. However, if left too long in the same pot with its roots confined, you will begin seeing symptoms that your plant isn’t all that happy.
Why Rootbound Rubber Trees Aren’t Thriving
But, wait? What about the argument that some plants “like” to be rootbound? I think a more appropriate word is “tolerate.”
Some plants, including Hoyas, Peace Lilies, and succulents, will all tolerate snug pots. And while it’s true that African Violets only bloom when they are rootbound, it is because they sense they are running out of resources and may die. I wouldn’t say any plant “likes” being rootbound. If plants did actually prefer tighter spots, I think we’d see many more examples of this happening out in nature.
In regards to your Rubber Tree gradually getting more rootbound, it will definitely tolerate it up to a point, but after a while, it is going to start showing signs that it is no longer thriving and is actually quite stressed out in its current environment.
Rootbound plants can get so tightly wrapped that they have trouble absorbing water and nutrients from the surrounding soil, most of which has been pushed out and away from the root ball. Without adequate soil surrounding the individual roots, water tends to flow too quickly past them for any efficient absorption to occur.
You may also notice that keeping your plant properly watered becomes difficult. You may have to water more frequently, as more root matter overtakes the inside of the pot, and water flows out the bottom without the soil being able to soak much of it up.
The most obvious sign that your plant isn’t thriving due to being rootbound is that its growth with slow significantly. This is more obvious in Rubber Trees, due to their faster growth rate. Because water and nutrients aren’t readily available to support new growth, the plant slows down to redirect what resources it has left towards staying alive.
Sometimes, people use small containers to control the size of their Rubber Trees. Once rootbound, the plant’s growth slows, and it can be at a certain height for longer. If you choose to do this with your Rubber Tree, I would recommend that you pay extra attention to your plant’s health, watching out for the signs above, and don’t restrict it for more than one season.
A very rootbound Rubber Tree will need many roots trimmed away when it is next repotted. This can cause a lot of undue stress on the plant, and it might not acclimate well to its new pot.
When is it Time to Repot a Rubber Tree?
If you’re like me and want to stay ahead of the game, before your Rubber Tree gets too rootbound, you should occasionally pull your plant from its container to check how the roots are growing.
You can carefully tip your Rubber Tree over and slide the root ball out of the pot. If you notice lots of visible roots beginning to wrap around the sides and bottom, consider potting up to a bigger container. The new container should have about one to two inches of space between the roots and the edge of the pot.
If this chore has slipped your mind for a good while, you might start seeing some of the detrimental signs that your Rubber Tree is getting rootbound. If you notice slowed growth or nutrient deficiencies, or drooping leaves (both signs of poor water uptake), remind yourself to check the pot and see if your plant has outgrown it.
Final Thoughts
While it is true that Rubber Trees will tolerate being rootbound to a certain extent, they can only truly flourish when given adequate space to spread their roots. By repotting your Rubber Tree occasionally, you’ll be rewarded with lots of vigorous, healthy growth and a truly stunning houseplant.