Planting and watering a tree to ensure establishment


The other day someone asked me “when is the best time to plant a tree?” and jokingly I responded “20 years ago.” I was referring to the old Chinese proverb that says: “The best time to plant a tree was 20 years ago. The second best time is now.”

Lucky for you, now is a great time to plant a tree in the Rio Grande Valley. Late fall to early spring is the ideal time frame to get your new trees in the ground. Planting during this window allows the tree to establish its root system before the rains and summer heat stimulates new growth above the soil line. It’s important for the root system to be well developed as it will be working double time during the summer to provide enough water for the upper portion of the tree.

Before we discuss the best steps for planting and watering your tree to ensure its establishment, let’s start with some terminology.

>> Drip line is the edge of the tree canopy where rain would naturally fall to the ground.

>> Support roots are the large roots that give support and anchor the tree.

>> Feeder roots are smaller, lateral roots that take up the majority of water and nutrients.

>> Root flare is where the tree truck gets wide and meets the soil line.The quality of the hole you dig for your new tree is just as important as the quality of the tree itself.

>> Dig the hole twice as wide as your root ball and only as deep as the root ball. You want a solid, firm surface to set the root ball on to so that it doesn’t sink down after watering and a nice wide hole so that the lateral roots can easily expand.

>> If the tree was in a container, be sure to prune any circling roots. If left unpruned, they may continue growing that way instead of laterally reducing the tree’s ability to uptake water and nutrients. Additionally, the lack of lateral roots can weaken the tree’s stability during strong winds.

>> Once you have set the root ball into the whole, fill the hole halfway with soil and then water to help it settle around the roots. Then, finish filling the hole with the remaining soil. The root flare should be just above the soil surface line.

Your final step is to add a 3- to 4-inch layer of mulch around the tree to reduce weeds and retain soil moisture. Be sure to keep the mulch 2 to 3 inches away from the truck of the tree. Mulch should never be piled around the trunk of a tree.

This simple watering schedule will keep your tree happy and growing:
>> Month 1 — water three times a week.
>> Month 2 — water two times a week.
>> Month 3 — water once a week.

Only water in the absence of rain. Make sure to water the root ball, not the tree trunk. Another standard for watering is to give the tree 5 gallons of water per each inch of caliper.

You can measure the caliper or diameter of the trunk 12 inches above the soil line. Follow these tips and 20 years from now you will be enjoying the beautiful tree you planted today.

Ashley Gregory is the the horticulturalist for Hidalgo County with Texas A&M AgriLife Extension Service. She can be reached at the Hidalgo County Extension Office at (956) 383-1026 or by email at