Cooler autumn temperatures help reduce transplant stress and moisture loss. As long as the soil temperature is above 50°F the roots of the tree are still growing. This extra time, typically into mid-November in Iowa, enables roots to get some extra growth before going fully dormant.
Soil Temperature & Garden Plants
Autumn's arrival might even bring more rain than the hot and dry weather we've had lately and typical of late summer. Combine this with the cooler temperatures and your trees might not use as much water as they would during the spring growth spurt and summer heat. Even during the fall your newly planted tree will still require watering, however, especially to hydrate the subsoil well going into winter.
One thing to consider is that these recommendations are for potted or container trees. We don't plant dormant bare-root material in the fall in our climate. They are hard to keep from drying out and winter will almost certainly kill a bare-root tree planted too late in fall in the North. Early spring is a much better time to plant bare root trees!"The best time to plant a tree was twenty years ago, and the next best time is now!"
When winter arrives your care activities can "chill out" for a few months, but...
You'll want to keep young trees protected from deer and rabbits (more on that here)
Ask an Arborist: Why Should I Plant in the Fall? (youtube.com)
You might be wondering "How do I plant a tree well?" Here is a quick overview of how we plant our trees-
Step 2 - Remove the container and break up/cut any pot bound/circling roots, place in hole, and backfill about halfway. Make sure tree is straight and plum.
Step 3 - Deeply water around the tree letting the water settle the soil. Finish backfilling and watering.
Step 4 - If needed tie up tree for stability. Two T-posts at the North and South sides, driven outside of the excavated area, are usually enough. Tie using wide straps with enough tension to allow flexing to strengthen trunks, but not so loose to tip or lean in strong winds.
Step 5 - Mulch in a ring 4'- 6' in diameter, 3-4” deep with hardwood mulch. Leave several inches between the mulch and trunk to prevent fungal infection.
Avoid the mulch volcano... instead go for a mulch donut!
Over the next few weeks and months observe and water as necessary until the tree is fully established.
Water daily for 1-2 weeks; then 2-3 days for 3-12 weeks; then weekly until established
Apply 1-1.5 gallons per inch of caliper (trunk diameter) at each watering
If the ground does happen to thaw in winter, it would be a good idea to try and see if you can get some water to your young tree. Winter's drying winds can evaporate moisture from the soil, especially if we don't have a protective blanket of snow.
A smaller tree will take nearly a full growing season to become fully established. A 2" tree may require two years to become fully established on its own while a 3" tree may need three years. The larger the tree, the bigger the shock so continue to be diligent and observant even long after the initial planting and water accordingly.
"A society grows great when old men plant trees under whose shade they know they’ll never sit."
Need help planning and planting this fall? Abundant Design offers Consultation, Design, Installation, and Stewardship services. The fall offers a great opportunity to plant, and it’s also a great time to start planning and designing for next season. We can help!
