Fall is for Planting

9/24/2020

The best time to plant is 20 years ago. The second best time is today.

Why fall? Well, the truth is you can plant trees anytime of year (assuming the ground isn't frozen, of course). But fall is the most ideal time to plant for a number of reasons:

Tree can focus on root development instead of supporting leaf growth.
Temperatures are typically moderate with less chance for trees to be stressed by extreme heat.
Frequent rains helps trees establish their root systems.
When the air temps are cooler than soil temps, new root growth is encouraged without new top growth, resulting in stronger root system before spring.

What to plant:

Right Tree, Right Place. This concept ensures what you're planting has room to grow (see next section below) and will last long term.
Species Diversity. Diversity is important for many reasons, most important of which is to lessen the devastation from yet another foreign pest decimating a species (chestnut, elm, ash, etc.). Don't put all your eggs in one basket.
Maximizing the Ecosystem Services. Consider planting with a purpose. Improving air quality? Absorbing the most stormwater possible? Certain species do more than others. Check out these resources: Arbor Day Foundation's Tree Guide, iTree suite of tools has a species selector tool, Trees and Design Action Group (TDAG) out of the UK has a Species Selection for Green Infrastructure guide, or University of Florida Extension has a good resource on species selection.

How much space do I need?

Make sure your tree(s) has enough space to grow to its mature size in order to provide the maximum benefits. Trees need room to grow in relation to each other AND above ground / below. Tree soil should have a minimum depth of 3 feet, but ultimately soil volume for the mature size of the tree is the critical factor to consider.

Small trees (30' or less at maturity) should be spaced at least 10' apart and at least 8-10' from a building foundation. In general, these trees are ok to be placed under utility wires and need around 300 cubic feet of soil volume.
Medium trees (30-70') should be spaced around 30-40' apart and be placed at least 12'-15' from a building foundation. This tree group should not be planted directly under utility wires. Required soil volume is approximately 600 cubic feet for long term growth.
Large trees (70' or more) should ideally be spaced 40-50' apart and no less than 20' from a building foundation. In addition, these trees should be planted well beyond utility wires. Required soil volume is approximately 1,000 cubic feet to ensure long-term success.

How to plant:

One of the questions that many ask is how to properly plant a tree. That depends on what form your tree is in when you purchase it. The National Arbor Day Foundation provides simple instructions AND videos on how to plant each of these types of trees you might get from a nursery.

How to care for your new tree:

New trees need care for the first THREE years after they are installed.

Watering new trees is an important establishment task. Here are some helpful resources to learn when and how much to water your new tree. The Arbor Day Foundation has a great page on how to properly water new trees. A California ReLeaf member, the Vacaville Tree Foundation, also has a good summary on how to water new trees.

Annual mulching in a ring around the base of the tree ensures moisture stays in the soil, weeds are kept to a minimum, and reduces the risk of mowers and string trimmers damaging the trunk. NOTE: Do NOT allow "volcano mulching" that piles mulch up against the trunk!

After 3 years, it is recommended to perform structural pruning to ensure the tree has a good form for future stability and to minimize future storm damage. Casey Trees, another non-profit doing good work in Washington DC, has a series of videos on young tree pruning. Check out their page on YouTube for some great directions to complete this important task.