Trees and shrubs planted in containers work well in many outdoor areas – but they’ve got special maintenance needs. For starters, the plants typically require more frequent watering and fertilizing than those planted in the open ground since potting soil usually dries out quickly.

Container shrubs and trees work well in small places, but they need special care.

Photo Credit: Sarah Landicho

If you plan on moving your trees and shrubs after they’ve been planted, ask a friend to help you move the filled, heavy pots onto raised, rolling platforms and carefully push the plants to their new location.

Photo Credit: ©2002 Dolezal Publishing/John M. Rickard

Containerized trees and shrubs need extra fertilizer because nutrients leach out with regular watering.

Photo Credit: ©2002 Dolezal Publishing/John M. Rickard

Some containerized trees need to be staked to provide proper support for the plant.

Photo Credit: ©2002 Dolezal Publishing/John M. Rickard

Protect your contained tender plants from frost by installing stakes and wrapping the plant in sheet plastic with ample breathing holes – or move them inside if temperatures dip too low.

Photo Credit: ©2002 Dolezal Publishing/John M. Rickard

But the amount and frequency of watering required depends on lots of things, including the size of the container in relation to the tree or shrub it contains, the amount of sun the plant receives and the porosity of the container. The ultimate goal is to keep the potting soil moist during the growing season, without letting it stay overly soggy – something that’s not always easy to do.

The best way to determine when to water your container tree or shrub is to simply press your finger 2-3 inches into the soil. If the soil is dry at that depth, treat your plant to a good soaking. (You’ll probably notice that during the dormant season – when it’s normally rainy – you’ll need to water less often, if at all.)

Of course, one side effect of watering container plants so frequently is that nutrients, which reside as salts and minerals in the growing medium, are leached – or dissolved into the water – and carried away. To keep your containerized tree or shrub healthy, you’ll need to fertilize on a regular basis, either by applying a water-soluble fertilizer or by sprinkling granular fertilizers over the top of the container soil. Regardless of which type you use, it’s important to carefully read and follow exactly all package directions regarding timing and amount.

In addition to regularly watering and fertilizing container plants, there are some other maintenance tasks you should perform on occasion. If your plant is stagnating, or if you’re having to water on a daily basis even when temperatures are moderate, you most likely need to repot the plant – placing it in a larger container. It’s best to use a pot with a diameter of just 4-6 inches wider than the current container. When repotting, be sure to fan out the root system, unwinding any roots that growing in circles around the interior of the old pot. Then water the plant thoroughly after repotting and apply a finishing layer of mulch over the top of the soil.

It’s also a good practice to gently remove the top inch of soil from the container every other year and replace it with fresh potting mix. And every 4-5 years, take the whole tree or shrub from its container for remedial root pruning. Just cut back the tips of all the visible roots and prune out most of the larger, woody roots before repotting. Generally, you can return the plant to the same container. Finally, strip leaves equivalent in area to the quantity of roots removed to help the plant adjust, begin new growth and quickly recover. You should begin to see new foliage sprouting in about 3-4 weeks.

Following this simple maintenance routine will keep the root system of your contained tree or shrub healthy, as well as prolong the life of your potted plants.