How to Save Seeds from Sweetgum Trees

Sweet gum trees (Liquidambar styraciflua) are beautiful trees and are great to have around for wildlife. The seeds of the sweet gum tree are eaten by small mammals like squirrels and chipmunks as well as a number of birds including finches, ducks, quail, chickadees, sparrows, towhees, and Carolina wrens. With all that wildlife enjoying the sweetgum trees I can easily get over the annoying aspect of the sweetgum seed balls.

Sweetgum Tree Seed Balls

Sweetgum seed balls are an aggregate fruit that when dried out can be harvested for seed. Once dried out the seed balls release the seed where birds can chow down so the key to saving the seeds is gathering the seeds when they are still green.

Sweetgum seed balls have hard small spikes that can be very annoying when mowing over or walking through the yard. Sweetgum seed balls have a couple possible uses as a mulch, in compost, or even as household decorations.

If you don’t like having the spikey corona virus lookalikes around rake them up and toss them in the compost bin after they have had a little time to dry and release their seeds. You will likely have some seeds in your compost so if you are at all concerned about volunteer trees popping up then don’t go this route. You could place them in a black plastic bag filled with leaves and place them in a warm location to cook into the leaf mold.

Use a Mulch for Animal Deterrents

If you use the spikey balls as a mulch they may act as a deterrent to a few animals that tend to dig in the beds (thinking about those feline friends that may be using your garden beds as a litter box). It may also prevent deer, rabbits, and other garden pest from walking through your garden. I say MAY because I suspect it will only be a short term deterrent.

Pick the Right Location for Planting a Sweetgum Tree

If you plant sweetgum trees make sure you select the right location. Anywhere close to a house, structure, sidewalk, city street, or driveway is a bad location for a sweetgum tree. They will drop seeds and you will end up with a mess to clean up. A sweetgum tree will easily grow to 60 to 75 ft tall and 40 to 50 ft wide and is not a tree selection for planting anywhere near a home. The root systems could damage foundations or septic areas. The mass of leaves and see balls going into the gutters would make a perpetual maintenance issue.

So where should you plant a tree like a sweetgum? Try the outskirts of your yard where you can enjoy the amazing fall color. Putting a sweetgum tree on the edges of your property will attract wildlife to those areas and the seed balls won’t be as big of an issue.

Sweetgum trees should never be planted along city streets unless using a smaller variety like ‘Slender Silhouette’ which grows in a column form (50ft tall and 4ft wide). Another alternative is a hybrid sweetgum ‘Rotundiloba’ (60ft tall, 30 ft wide) that does not produce seeds. The leaves are more rounded and less star shaped than American sweetgum trees.

How to Seeds from Sweetgum Trees for Planting

The tricky part of saving seeds from Sweetgum trees is that I have always had trouble catching the seed balls at the right time. In order to save the actual seeds you need to collect them when the seed balls are green. The problem is usually when they are green they are still attached high up in a tree! We were able to find some after a wind storm that had been knocked off the tree. Brown seed balls will likely have already released their seeds but there may be a chance to find a few in there.

Once you gather the green seeds place them in a paper container or as in the video below I used a cardboard egg carton. Plastic products will hold in moisture which will cause rot and mold to appear. The cardboard egg carton or paper bag will allow the air to breathe and the seeds will release into the container. Check it after a few days and in 4 to 6 days they should have opened up to release their seeds. Shake the container and you will seed small winged seeds and a whole lot of other material.

Cold Stratification

Put the seeds in a paper envelope and place in your refrigerator for at least 30 days. Sweetgum tree seeds require a 30 to 60 day stratification period for good germination. A longer period is fine but at least 30 days.

The cold stratification process mimics the outdoor winter temperatures and helps the seeds to know it’s time to wake up and grow by breaking the dormancy period.

Once the seeds have had their cold stratification period you can place them in a pot with a good potting mix for germinating. It should take 4 weeks or so for the sweet gum seeds to germinate. Below is a short video showing the results of planting the seeds from the earlier sweetgum seed video. Enjoy!