The Basics of Growing Trees and Shrubs in Pots

A small light green tree and darker green shrub in white pots

The Spruce / Gyscha Rendy

Whether you are limited on space, growing plants that don’t usually survive your local weather or just looking to create focal points, container trees and shrubs can be a lovely addition to your landscape. There are some considerations that you will need to remember to help them stay happy and healthy.

Research to Determine What Trees and Shrubs Are Best

One big mistake that some gardeners make is falling in love with a plant online or at a nursery and whisking it home with nary a thought as to whether it will work in your garden. This is especially true when you are trying to place a tree or shrub in a container. The cute little sapling that you spied at the garden center can turn into a tree that is over 100 feet tall.

The basics that you should check out for potential candidates include:

Use Dwarf Cultivars as Available

You are asking a lot of a tree or shrub when you place it into a container. The roots have far less space to work with and can naturally become crowded. When you choose dwarf cultivars and species that are naturally on the smaller size, it is easier for them to adapt to the limited area presented. This is especially important when you are working with fruit trees since they will need extra energy to produce fruit and you want a good root base.

Dwarf cultivar tree in a pot within wooden area

The Spruce / Gyscha Rendy

Choose Your Pot Size Carefully

Picking the right size of the container for your tree or shrub can be a bit tricky at first. You do not want one that is too small, of course, as this will leave little room for root growth and it is likely to become rootbound and struggle or die. Since it is a large plant, you might naturally think to place it in a very large container so it will have room even when it is fully grown.

You can run into problems if the pot is too large for the plant’s current size. When soil present is abundant and not enough roots to take up the water, it can retain moisture for too long and cause root rots that can ultimately kill the plant.

For best results, plan on moving up in 2” increments every couple of years until it reaches maturity. Repot sooner if you notice roots escaping from the drainage holes. If it is rootbound when you change containers, perform root pruning by using a box cutter or other sharp instrument to score along the sides of the root ball and remove the mass of roots. This will stimulate new root growth and keep the plant healthier.

Drainage is Essential

Even if you have the correct size of the container, you can run into root rot and other problems if there are not enough drainage openings present. Check your pot and use a drill to create more as needed.

Protect the Roots in Freezing Weather

Many trees and shrubs have adapted for survival through the harsh conditions present during winter. Growth slows, and the plant goes into dormancy. The roots are protected by the ground surrounding them, and the temperatures are at least a little higher than in the air.

In a container, there is a lot less buffer present for the roots. It is much easier for the soil to freeze completely and cause damage. Options are to bring the plant inside, bury it in the ground or place it somewhere like a garage or basement. If you choose to bury them, add mulch on top for extra protection and leave a space around the trunk to prevent insect and disease damage.

Dwarf tree in a pot with branches that have frozen leaves and twigs

The Spruce / Gyscha Rendy

Don’t Forget to Harden Off Your Plants

If you are trying to grow plants in containers so that you can bring them inside when the temperatures drop, take it slow when you reintroduce them to the outdoors in the following spring. This process is called hardening off and is an essential step in protecting your trees and shrubs from harm.

Imagine that you are used to sitting quietly on a couch while listening to classical music. One day you are drifting off into a nap, but suddenly are jolted awake as someone throws you into the front row of a rock concert. This is the sort of experience that a plant will be subjected to if you do not harden it off first and let it adjust. Outdoor conditions are harsher than indoors since the light is magnitudes brighter, environmental conditions like drought, salt and wind are present, and insects or diseases are more likely to strike.

Instead, start by carting your plant outside for an hour or so for a couple of days. Gradually increase the length of time it stays outside over two weeks. After that, it is ready to spend the growing season in your landscape.