Seedless Trees: Blessing or Barren?
Mancana Manchurian Ash, Lace Weeping Willow, Ming Cherry, Gentry and Nobility White Ash, Spring Snow Flowering Crabapple, Northern Acclaim Honeylocust, Patmore, Trojan and Prairie Spire Green Ash, Autumn Blaze Maple, Skyfest and Siouxland Cottonwood as well as various hybrid Poplars and even more varieties after that. These are some of our top selling, best known trees in the nursery business. What do they all have in common?
They are all seedless.
More accurately, they are all male trees or hybrids, a cross of two different species, which results in them being sterile.
I can understand the desire to have seedless trees. I remember helping out at my grandma’s house, sweeping up the mountains of Elm seeds that showered the yard in summer. I have had to pull up young seedlings of Elm, Maple and Ash that have sprouted in my garden or flower beds many times. Seedless trees can also plug your air filters or air conditioner with fluff from the poplars and willows. Also, seedless trees do not drop fruit that attracts wildlife or insects. What more can we ask for?
But there is one thing that seedless trees do that many people do not stop to consider. A male tree will not make seeds, but they will produce pollen. Many people choose seedless trees because of allergies, but it is often these male trees that are the biggest culprits.
Another issue that can arise from using only seedless trees is that they must be reproduced by cutting, grafting or through tissue culture. Often these are more expensive means of production. It also means that each tree produced is an exact clone of the original parent. Genetically identical. This has advantages as you can then guarantee things like growth rates, fall colour and cold tolerance. But it also means you cannot develop any improvements. Any weaknesses in cold tolerance or disease tolerance apply to each tree produced equally. That is why Bronze Leaf Disease (BLD) did so much damage in Southern Manitoba when it arrived. All of the tower poplars, green from cuttings, had the exact same weakness to the disease and it spread like a wildfire.
Male trees are also a difficulty in production because they cannot reproduce seedlings for future research. All these amazing seedless varieties we sell today only exist because someone planted and kept a tree that produced a seed and one of them became the Mancana Ash, or Spring Snow Crabapple.
The tree market cannot grow from seedless trees. A seedless tree is an amazing find at the dead end of a road. A seed-bearing tree is a cross raid with a hundred different options to pursue, some of which will also lead to more amazing views we cannot even imagine today.
In the end I suppose we need both to keep the production and sales working in the nursery business.