As we all say goodbye to winter and embrace the change of season to spring, our industry starts planning for bareroot planting.
For most of our industry – including ball and burlap nurseries, containerized nurseries, greenhouses, garden centers, and Christmas tree growers – now is when we are receiving bareroot plants. Often, these plants arrive at the very beginning of what we hope will eventually become spring, but they continue to trickle in as suppliers dig plants. The collection of plants varies by customer classification but often includes shade trees, fruit trees, shrubs, roses, small fruits, and perennials.
The industry is attracted to bareroot plants since they are often the most affordable option. However, one of the biggest problems with bareroot plants is that they deteriorate in quality when they are not quickly planted and either become unsaleable or not worth planting.
This article will cover how mycorrhizae fit into the use of bareroot plants in the horticultural industry.
Why Use Mycorrhizae with Bareroot Plants
Bareroot plants go through a shock stage when they are dug up, sorted, stored, and shipped. Mycorrhizal fungi help these plants adapt to their new surroundings, efficiently absorb a more significant portion of the nutrients, more effectively capture available water, and help the plant fight back against abiotic stress.
How Mycorrhizal Fungi Connect with Bareroot Plants
Mycorrhizal fungi do this by connecting with the plant and increasing the plant’s root mass. The root mass is composed of the plant’s roots, root hairs, and the mycorrhizal hyphal network. The expansion of the root mass comes from the growth and development of the mycorrhizal hyphal network.
Growers do not need to worry that a mycorrhizal plant will become root-bound sooner.
The mycorrhizal hyphal network extends both beyond the root depletion zone (current root’s area of influence) and in areas within the root depletion zone that are not accessible by the roots and root hairs. Mycorrhizal hyphae are one-tenth the size of a root hair. Over time, the expanded root mass can expand to 50 times the size of the original root mass. This can mean an extension of up to two feet beyond the outermost roots in a plant grown at a ball & burlap nursery, or the greater capturing of nutrients and water within a container.
The increased absorptive area is hard to imagine unless we view a 3-D root image. You cannot always see the difference when you “pop” a plant out of a pot. The mycorrhizal hyphae are better than roots at absorption. Nutrients and water are absorbed along the entire length of the hyphae compared with just the tip for roots and root hairs. On top of that, mineral nutrient uptake through hyphae can come from both the soluble and insoluble pools of nutrients. And to ensure uptake efficiency, mycorrhizal hyphae allow for greater inflows through their system. Plants with mycorrhizal relationships develop better root absorption systems, which increase nutrient and water uptake by the plant.
What Type of Mycorrhizal Fungi Do I Need?
Mycorrhizal fungi come in several distinct types.
- Endomycorrhizal fungi treat most greenhouse crops, perennials, fruit trees, many shade trees, numerous shrubs, and most small fruits.
- Ectomycorrhizal fungi form associations with conifers and a variety of shade trees.
- Ericoid mycorrhizal fungi treat plants in the Ericaceae family. Rhododendron, Azalea, and Blueberries are all ericaceous plants. Unfortunately, this type of mycorrhizal fungi is not commercially available. Note that ericaceous plants are not negatively impacted when treated with an Endo or Ecto mycorrhizal fungi.
To learn which mycorrhizal fungi a specific plant forms associations with, I suggest you refer to our Mycorrhizal Status of Plant Families and Genera database.
One Size Fits Most – MycoApply® Soluble MAXX
MycoApply® Soluble MAXX has both Endo and Ecto mycorrhizal fungi in it. In fact, it has the largest concentrations of both Endo and Ecto mycorrhizal fungi in the products that Mycorrhizal Applications offers. Ball and burlap nurseries, containerized nurseries, greenhouses, garden centers, and Christmas tree growers that will be planting a variety of types of bare root plants can benefit from the use of MycoApply® Soluble MAXX.
There are two options for applying MycoApply® Soluble MAXX.
- Dip the plants into a container containing the mycorrhizae.
- Apply via a root spray.
In both circumstances, make sure the final solution remains agitated. This is important because mycorrhizal fungi propagules go into suspension and not solution. One pound of MycoApply® Soluble MAXX will produce 26 gallons of treated solution. The product also contains both kelp meal and humic acid to support the work of the mycorrhizae.
Let’s Take a Dip (or Spray)
If you plan to do a plant dip, most growers work with a five-gallon bucket. You start by thoroughly mixing up 3 oz. (85 grams) of MycoApply® Soluble MAXX in a water-filled 5-gallon bucket (which is roughly 19 liters). The bucket needs to be large enough to submerge the entire root system of the plant into the suspension. You do not want to submerge the above-ground portion of the plant. The plants should stay in the suspension for at least 10-15 seconds, but the length of time can be longer. With this pause, the plant root system tissue is able to absorb the suspension completely. We suggest you use disposable gloves when you dip your plants.
If you are going to spray, use filters or screens no smaller than #50 mesh in your application equipment. Do not forget to keep your bucket or sprayer solution agitated, and be sure to plant immediately. We do not suggest allowing plants to remain unplanted after treatment. As always, please refer to the official label for more specific application instructions and safety details.
Special Note for Retail Garden Centers
If you are a retailer reading this, here is a thought. Rather than selling your bareroot plants as is, it might make more sense to transition the plants into a higher value product offering. With the purchase of some nursery containers, fertilizer, and a growing mix, these bareroot plants can be planted into the containers and transformed into an offering sold at a premium price. The addition of mycorrhizae will help the plants transition more quickly into growing leafed out plants, making them sell more quickly, and look the part to justify the premium price.
If you have any questions about anything covered in this article or MycoApply® Mycorrhizae, please contact your local Mycorrhizal Applications Representative, call 866-476-7800, or email us at inquiries@mycorrhizae.com.
March 26, 2025
Article written by Blair Busenbark, Key Accounts Manager at Mycorrhizal Applications, Blair.Busenbark@mycorrhizae.com
