For the first time this year I noticed pea sized fruits on my magnolia tree and I wondered – will magnolia seeds grow and how do I go about it?
Commercial propagation by layering is generally more successful and creates magnolia trees of flowering size quicker than by seed. In the wild, however, dispersal by seed is the norm so it’s always worth a try.
Do the seeds need a period of chilling and should they be separated from the fleshy fruits? Here I show how to prepare the seeds to plant next spring.
Magnolia tree seeds
I have two magnolias in my garden, a magnolia soulangeana and a magnolia kobus. Both these trees are species varieties. This is important as named hybrids are unlikely to come true from seed and may be sterile.
I have never noticed ripe seed on either tree but this year some fleshy fruits were clearly visible on the Kobus. Otherwise known as the Northern Japanese Magnolia or Kobushi Magnolia, this tree is native to Japan and Korea. I chose it for its beautiful white flowers, which aren’t particularly large but are stunning in form.
Since summer, I have noticed pink narrow cone-like structures. These have developed previously but for the first time this year, bright pink spherical shapes also developing. These split in late October to reveal red fruits.
The colour contrast of pink and red is very appealing. No doubt our feathered friends also had their eyes on them and with good reason. Magnolia seeds are dispersed in the wild by birds. Indeed any seed encased in a fleshy fruit is likely to be dispersed this way.
It’s useful to understand this as it guides how people can mimic naturally occurring processes to prepare seeds for germination.
In the wild, the fruits would be eaten whole by a bird and then excreted out some distance from the parent tree. The bird will have digested the fruit, leaving the hard black seed behind in its poo.
I collected my seed and then used my finger nails and a knife to scrape away the fruit. The flesh of the fruit is white underneath the red skin, and is fairly firm. Removing the flesh is a fiddly but not unpleasant task as the flesh has a citrus scent.
Each fruit contains one seed. The seeds are jet black and shaped like a tiny flat broad bean. I soaked the seeds for a while in warm water to help clean the remaining white flesh from the seed.
Chilling the seed
Back in the wilds of Japan, the magnolia seed will not start germinating as soon as it leaves a bird’s backside. Instead, winter will set in and the seed will experience a period of cold weather before it starts to sprout in spring.
We can mimic this at home by chilling the seed in a fridge for a three month mock winter. The seed should not be allowed to dry out so placing the seeds in a bag of moist compost or vermiculite will ensure they stay in peak condition. This process is described in many books as stratification.
Planting the seeds
After 3 months in the fridge these seeds will be potted up individually in pots of compost. I will keep them somewhere fairly warm, probably in my greenhouse but equally a warm windowsill would do and keep my fingers crossed that some will germinate.
Some fellow gardening bloggers have contacted me to say they haven’t always had good results with fridge based chilling. It’s possible that the constant temperature of a fridge doesn’t adequately mimic the winter temperature variations of the parts of Japan and Korea where these grow.
A suggested alternative method is to plant the seeds in pots of sharp sand, or a sandy compost mix and leave them outdoors for the winter.
I have decided to try this method as well and report back next year to see which (if any) germinated.
Even if they germinate, it will take at least 10 years for a tree to reach a decent flowering size. Growing magnolia from seed is a long and uncertain game but the tree has gifted me these seeds and I feel it’s worth a go.