How to Fertilize Japanese Maples in Pots
- Relaena Sindelar
- Feb 8
- 2 min read
Updated: Mar 20
by Ryan Shields of Spruce and Maple;
Photos courtesy of Anthony Fajarillo of Bonsaiko
Applying fertilizer to a Japanese Maple that lives in a pot requires special care. The following Tips are provided by Ryan Shields, owner of Spruce & Maple Nursery in Collierville, Tennessee
Timing:
In early spring, your tree is going to push top growth. This is the time to apply fertilizer if you’re going to. Just be sure to do it when the pot temperatures remain consistently at or above 70 degrees.
Spring Fertilizer:
I ALWAYS use a 90-day slow release, typically in the following profile:
N (nitrogen) - 10-15 range
P (phosphorus) - 9-12 range
K (potassium) - 9-15 range
...or anything in that range. 10-10-10 or 14-14-14 is often readily available to the public, and those would be okay too.
Make sure your fertilizer is slow release if you’re using anything that has over 9 on your N rating.
Summer Fertilizer:
In the summer, you can follow up with an instant release fertilizer to promote root growth. That should be around the time your 90 days of slow release spring fertilizer has worn off. At this point you can focus on a fertilizer with more P/K (phosphorus and potassium) to promote root growth.
Amount of Fertilizer:
In all cases, read the label to make sure you add the right amount for your pot size. If you make a mistake and put an instant release down with high N rating, you run the risk of burning your trees and plants.
Watering:
During spring, make sure you don't over water. Your roots aren’t technically growing much, so they need to stay on the dry side. Under-sized trees can die from drowning or over watering.
In the summer, your potted maples can tolerate a lot more water than usual.
In Case of Emergency...
If you ever apply too much fertilizer and you’re worried about phytotoxicity (fertilizer/chemical burn), you can get a product called Charzorb (see directions for use here), or any activated charcoal product. It will absorb the nitrogen and hopefully keep your plants from getting fried.
Start by removing as much fertilizer as possible by hand; use a blower to remove even more. Place Charzorb on the spill. Whatever you do, do NOT use water to wash it out or off, as that will activate the fertilizer.
Ryan Shields is the owner of Spruce & Maple, the "shadiest nursery for Japanese Maples and other ornamental trees and plants" in Collierville, Tennessee.
