Time to Plant Trees Here, But Citrus is Tricky

Fall is the best time of year to plant trees and shrubs.

Cooler weather places less stress on trees, allowing them to grow a deep root system during the winter. Deciduous trees drop their leaves in the fall, and enter a period of dormancy. But they’re not dormant below ground. Their roots continue to grow.

If you plant trees or shrubs in the spring, they’ll put most of their energy into growing leaves and branches to the neglect of the roots. Then when hot and dry weather arrives in summer and plants go into stress, a weak root system may not provide enough water and nutrients to keep the tree alive.

There’s also a right way and a wrong way to plant trees. Many people plant them too deeply. If you look at the base of any tree, you should notice the root flares. The trunk at the base should look like the buttress of a castle. These root flares should be above ground and exposed to the atmosphere. All trees in nature grow this way.

If you dig a hole the size of the root ball with vertical sides and plant the tree, the roots will tend to grow in a circle. The tips of the roots reach the hard soil at the edge of the hole you dug and turn back towards the loose soil in the hole.

Instead, you should dig a wide, dish-shaped hole. Make sure you dig the hole to the correct depth so that the root flare will be above the soil level. Sometimes nurseries plant the trees too deep in the pot to begin with. If you don’t see the root flare above the soil in the pot, you need to remove some of the soil from the top of the root ball. You may expose some of the roots by doing so. But don’t worry – you can cut them away and it won’t harm the tree.

After you set the tree in the hole you dug, don’t backfill the hole with compost or potting soil or any other product. Use the native soil that you dug out to backfill the hole. If you backfill with rich potting soil or compost, the roots will want to grow in it and not spread into the native soil. This will result in a shallow root system that is poorly anchored to the ground. You want the roots to grow deep and wide so that they reach moisture and nutrients during stressful times like the summer. The tree will also be better anchored to the soil and won’t blow down in strong winds.

I think it is a good idea to spread an inch or two of compost or mulch on top of the ground around the tree. This provides some nutrients to the tree as it grows. But more importantly, it helps to trap moisture in the soil. Just make sure you don’t cover the root flares with the mulch or compost.

Some people dig a bowllike shallow depression around the base of the tree to collect water. I don’t think this is a good idea. When the soil stays moist around the base, the roots stay compact and won’t spread. I want the roots to spread. It’s better, I think, to plant into a slight mound, as long as the root flares are above the top of the mound.

Some folks stake their trees or support them with guy wires. I do not think this is a good idea, either.

Wind blowing against the tree encourages the roots to better anchor it to the soil. You might feel the need to anchor tall trees with a small root ball that you buy from the nursery. I think it’s a better idea to select younger, smaller nursery trees. Older trees that have been grown in pots their whole life are more susceptible to stress after you plant them.

Finally, what kinds of trees should you plant? That’s a topic for another day. If you want to plant fruit trees, you need to research chilling requirements. Different varieties of fruit trees require a certain number of hours of cold weather during the year before they will set fruit. I recommend visiting a nursery that specializes in fruit trees. They can help you select varieties that will give you the best chance of success.

Finally, lots of people want to plant citrus trees, myself included. But I’ve learned the hard way that citrus trees are extremely difficult to keep citrus alive outside during the winter in this part of Texas. If you travel even just 50 miles south of here, you can often find citrus growing outside. But La Grange is just a little too far north for almost all citrus. If you really want to grow citrus in the ground outside, make sure you select dwarf varieties that you can insulate and cover when it freezes. Some folks have successfully grown Satsuma oranges and Meyer lemons outside, but not me. I lost a Meyer lemon tree last winter to the cold, even though I covered it. From now on, I only grow citrus in large pots that I can bring inside during a freeze.