Which Species of Maple Do You Want to Grow?

The most important step in growing your own maple tree from seed is to determine which kind of maple tree you are trying to grow. This will help you determine what time of year the seeds will be ripe for collecting and how best to treat the seed prior to sowing. Ontario’s most commonly grown native maples fall into two categories; soft maples, which produce their seeds in spring/early summer and hard maples, which produce their seeds in the fall. Red Maple (Acer rubrum) and Silver Maple (Acer saccharinum) are soft maples, which you may have noticed are beginning to flower now. It is also important to note the naturally occurring cross of the Red and Silver Maple, known as the Freeman’s Maple (Acer x freemanii) falls into this category as well.

The Sugar Maple (Acer saccharum) and the Black Maple (Acer nigrum) will flower later in the spring and their seeds won’t mature until the fall.

As you may know, there are many cultivated varieties of the very popularly planted Norway Maple (Acer platanoides) in our urban landscapes. It is important to be certain of the identity of the species of tree you are collecting seed from and choosing to propagate. In some cases, Norway Maple can be quite prolific in their seed production and will drop an abundance of seed which germinates easily and can take over our natural areas. 

Make sure to familiarize yourself with our native maple identification features to be certain you are collecting the correct species seeds. See identification features and other interesting facts for our most common native maples here on our website.

Seed Production

Commonly, maple seeds go by many names, including helicopters, whirligigs, whirlers or twisters, referring to the way they twirl and spin their way to the ground when released from the tree. In fact, these seeds, known as samara, actually consist of a pair of papery wings surrounding two seeds fused together.

Silver and Red Maples are flowering now, before their leaves emerge, and their seeds will mature in late spring. Red maple specifically, is one of our earliest flowering trees, creating a visible red haze when you gaze up into the canopy. After the flowers are pollinated, the paired seeds will begin to evolve in colour from green to pinkish, to bright red, before maturing to a dry and brittle straw colour, and falling to the ground.

Silver maple flowers and seeds are not quite as showy in their colour, but the seeds mature from green to the same straw-like colour before falling. They are however, much larger than their Red counterparts, as you can see in this size comparison below. 

Sugar and Black Maples produce clusters of yellowish flowers from April-May, typically before the leaves begin to emerge. Although Sugar maples rarely flower until they reach the age of 22 years, with a heavier flower set the older they are. In late June, the dark green double sided samara can be seen developing. It is not unusual for only one embryo of the paired seed to fully develop into a viable seed, although sometimes both may contain seed, or both will be empty. Seeds mature in the fall, usually from late September to October and begin to fall from the tree just before leaf drop.

The second most important step after identifying the species of tree in growing your own is to responsibly and safely collect high quality seed in order to grow your own native maple. Check out this great resource for more information and tips Collecting Sugar Maple Seed – Maple Leaves Forever

Once you have correctly identified the tree species, and carefully collected the seed, there may be a couple steps required before sowing. That all depends on the species of maple. The seeds of our hard maples, Sugar and Black, require a process called stratification. This is the method of treating the seeds similarly to what they would experience in nature after dropping from the tree. It is crucial to simulate the natural conditions in order for the seeds to break dormancy and germinate.

For our soft maples, Red, Silver and Freemans, they can easily be sown straight away after collection. No need to soak in water or stratify with cold treatment. You can even leave the papery wings on and just stick them right in the soil! It is important to note that due to the genetic variation of red maple, some seeds may require stratification. Here is a great opportunity for an experiment. You could direct sow some seeds, and begin the stratification method with others and watch for signs of germination. If they fail to germinate, follow the stratification process described below for a period of at least 60 days in cold treatment.

Stratification

For the maples requiring the stratification process, start by soaking your seeds in room temperature water for at least 24 hours. Depending on the quantity and your supplies at hand, you have a couple options as far as how to emulate the cold treatment. You can either place the seeds between moist paper towel and place in a ziplock bag (be sure to leave some air in the bag). Or you can mix the seed in with a combination of moistened peat, growing media, sand, potting soil etc. and place in a similar kind of plastic bag with air. Whichever method you choose, make note of the date you begin this process and place the bag in the fridge. The vegetable drawer is a great spot to keep them. The seeds must go through this cold treatment for approximately 90-120 days in order to push through their dormancy period. It’s important to check on them periodically (every 7-10 days or so) to make sure there is still moisture, that there is no rotting or mold, or if any early germination is taking place. If the media or paper towel is too dry, add a little water to moisten it.

Sowing

Starting out with a sterile, well-draining potting mix is very important. Push the seeds into a moistened media at least ¼”- ½” depth and water the seeds until moist. Sowing the seeds indoors in starter trays may give them a better chance at survival, not to mention, will protect them from hungry creatures! Water when the soil becomes dry, but be sure not to overwater, as this may cause the seed to rot and fail to germinate. Once the second set of leaves appear, transfer to a larger pot, if required, and relocate outdoors to a protected sunny location when the risk of frost has passed.

The soft maples can also be directly sown into moist soil outdoors, although they may be at more risk of being dug up, eaten, or trampled on. It would be advisable to carefully mark, mulch and monitor your planted seed to determine its success. We would love to hear from you and to share in your stories of collecting, sowing and growing your own maple tree. Please feel free to reach out, share and send pictures of your successes and/or lessons learned! Happy Spring and and Good luck growing!

Caitlin Ayling, caitlin@mapleleavesforever.ca
Horticultural Consultant, Maple Leaves Forever