When a Plant Gets Too Big

For my whole life, I have grown plants. My grandparents were farmers and I used to help in the garden. When not planting, I was making mud pies and other sculptures out of the clay-type dirt in my back yard. Therefore, it was natural that I go into Horticulture as a professional. I still make mud pies, only now I get money for it.

Now that spring is here, many gardeners take to the out doors to manhandle the plants in their gardens. This is when gardeners make those drastic changes in their garden's structure and move, prune back, downsize, transplant new specimens and even change its shape.

As plants grow, they do become bigger and can sometimes be problematic for either indoors or outdoors. If you want to grow an evergreen, such as a spruce, you do not plant it next to the front or back door because it will soon be blocking the entrance to the home. The solution to the problem is to cut the tree smaller (short-term solution because it will just grow again) or remove it from that place. Of course, the best thing to do is to plant it in the best place for the tree to be able to grow to its full size without impairment to its shape.

Gardening inside is very different from gardening out side. Our perennials , shrubs, trees and vegetable plants have access to all the sun, humidity, and air circulation they need to thrive when the temperatures outside are within the ranges the plants need to grow. On the inside, we have to provide the proper amount of light, water, humidity, and temperature for the plants. In addition, as in outside gardening, putting each plant in the ideal location allows it to thrive with very little care from us. Knowing what each plant needs, and how to give it to them is the key to successfully growing plants indoors.

In the same way, houseplants that are thriving often take over and outgrow their space. One can either cut them back (this is again a short-term solution and can only be done one or two times without disrupting the balance of the plant), or move them to a place where they can continue to grow bigger. After all, these tropical indoor houseplants do grow large in the wild, and will grow as large as the space will allow. Unfortunately, if you are like me and have limited space in your home, the best solution for the problem is to trim the foliage back for a brief time, and then in spring, cut the entire plant back to a manageable size.

I mentioned the spring because houseplants are tropical and thrive in the tropical-like season of summer here in the temperate zone. These plants have evolved in a 24-hour day with 12 hours of sunlight and 12 hours of darkness with high humidity and even temperatures: In other words, the summers of the temperate zones that mimic these conditions, at least for a few months. The closest to its optimum environment, the quicker it will come out of the stress of trimming and pruning and begin growing again.

To keep your huge plants in a manageable state, it is important to cut them back when they get too big for their space. You trim the top growth as well as the roots to keep the plant in its proper balance. This is something I have to do to my plants on a regular basis. They thrive in the summer and within a few years, they become so large they will no longer fit in the area where they need to be in order to get the proper amount of light for their good health.

In March each year, I have many plants that need downsizing, either because they are too big or because they have lost more than half of their top growth during the winter due to lack of the amount of sun light and short days, cutting down the amount of light they need to sustain all their top growth. Here in New England, we have an average of 85% cloud cover. That makes for very cloudy and bleak winter days. As a result, some of my light-loving plants will drop much of their top growth. These plants hang on until the light is stronger and more available. Then it is time to get them back in to balance again.

Doing a root prune along with a top prune, ensures that the plant will have the proper balance for optimum growth. There is a ratio in nature and everything grows according to this ratio. In plants, this ratio is 2/3 top growth to 1/3 root system, and it dictates how the plants grow. If you could go out in to the forest, and lift one of the tallest trees out of the soil and shake it all away, when you measure the amount of roots and the amount of top growth, you will see that this ratio exists in every plant you choose. If you look all of those planted containers of annuals in spring, when first planted, they always look funny because the top growth is too small. The ratio is not correct. The planter looks its best just before frost when the top growth and the roots reach that 2/3 to 1/3 ratio. That is, there is 1/3 more top growth than root system. Now the planter looks right and beautiful.

Many times when a plant comes to me by its owner for aid because it is struggling, the balance of top to bottom growth is usually off. All too often, the plant is in a pot that is too big for its root system. The roots cannot obtain the proper amount of moisture, and suffers because the amount of soil volume is too large and holds too much water for the plant to use. The result is over watering -catastrophic for the plant. If the soil does not contain enough water, then the plant becomes under watered-again catastrophic.

When I have to readjust the ratio of top growth to root system I do this by cutting both the roots and top growth, I always follow a simple rule. I remove the plant from the pot, and using a clean, sharp non-serrated knife, I trim the bottom of the root ball. How much I cut depends on now much I need to downsize the plant. I then stand the root ball up and trim the sides, cutting enough off according to how much I need to downsize. Then I transplant the root ball in to the proper-sized pot. Once the plant is in the new pot, I then cut the top to balance the plant.

I can estimate what the size of the new pot will be because I need to have the root system fill at least 1/2 of the interior of the new pot. If I use a pot where the roots do not fill at least half of the interior space, I can do much harm to the plant in the near future. If there is too much soil in the pot that holds more water than the plant can use, the roots will be in danger of rotting. A newly pruned plant is in severe shock, and will not grow until it repairs its damaged roots. You can tell when a plant has come out of shock when you see new growth on the tips. The plant cannot grow new top growth until the roots heal and the plant grows new feeding roots to replace the ones cut off. In the meantime, if the soil is too wet and the plant cannot use the moisture in the soil fast enough. As a result, oxygen is not available to the roots, and they will rot in the excessive moisture. Then the plant cannot hydrate the top growth. The top of the plant wilts due to lack of water in the cells of the leaves because there are no roots to bring the water to the top of the plant. It looks like it needs water, and all too often, you water it again, thinking the wilt is from lack of water. A. general rule of thumb: if the soil is wet, do not water the plant.

If I have pruned the plant so that ratio of 2/3 top growth to 1/3 roots is correct, the plant can begin to heal the wounds created when cut. I need to water the soil after I finished, because it is both light and water that helps a plant to come out of shock. When new growth appears on the top, I know the plant is out of shock and I can then use fertilizer to help the plant to begin growing again. (See the article on Fertilizer versus Plant Food.)

I often prune plants back to as much as ¼ of its size. As long as I cut the roots and top in the proper ratio, I know the plant will begin to grow as soon as it comes out of shock and will continue to grow through the summer. Then it will continue to grow until it becomes too large for its spot again. When take a client who wishes to place plants in a home or place of business, I always make sure that the owners will care for the plants correctly to ensure their well-being. When they outgrow their pots, instead of transplanting into larger one, I will come in and prune them so they will stay in the same pot and remain in the same space. Many times, the plants are accents for a particular space, and enhance that area and all that surrounds it. We want that plant to remain there for a years, and the pruning can ensure that will be the case.

Because many of my plants loose foliage each winter and need pruning in the spring, it almost seems hard to believe that these plants actually grow bigger. But they do, especially if I only prune enough to get the plant back into balance. If I do not downsize too much, the plant will get bigger over the years, even with the yearly pruning. In fact, some horticulturists recommend pruning the roots every time we transplant. The feeding roots, those thin hair-like fibers that are on the outside of the root ball, are what keep the plant healthy for years. Through these roots, nutrients brought in travel throughout the plant's system to nourish all its parts. By forcing the plant to grow new roots every year, the plant is able to keep them new and healthy, allowing the plant to nourish itself for years. This is the process in maintaining Bonsai specimens. Some of these specimens can live for many generations when properly cared for.