Can you dig it?
Spring is undoubtedly the craziest time of the year for all of us in this industry, with garden centers, landscapers, and nurseries all dealing with their own particular challenges. In the field nursery, we are trying to dig and plant during the same limited window of time, all while contending with the wet spring weather. Some of the most commonly asked questions we hear at this time of the year relate to dig times and whether specific trees and shrubs can safely be dug now.
There are, of course, general guidelines that you can use to determine when is the best time of year to dig any particular variety of woody plant (you can look to the dig calendar in the front pages of our catalog as a reference for the varieties that we grow). Some things, like birch, are spring-dig only, while others, like serviceberry and many of the crabs, can be dug in the spring or the fall. And then there are some evergreens, like Thuja and Buxus, which can be successfully dug throughout much of the growing season. But, within these guidelines, there are a lot of different factors that can influence when is the best time to dig any given variety in any given year. The understanding of these factors and how they are specific to any particular variety comes somewhat from guides and references, but also from trial and error and years of personal experience in the field.
Digging certain varieties when they are in a very specific stage of development can be critical to the success of the transplant. For example, Tina crabapples grown on their own root are particularly sensitive to transplant stress and need to be dug at just the right time. Hawthorn can be dug early, but if they’re not dug at the optimal time you may end up with very small leaves for the rest of the year. Some items, like Cornus mas, witchhazel, and most Viburnum, can actually be safely dug in the summer once they harden off.
When we talk about stages of development with regard to dig time, we are usually referring to things like how leafed out the tree or shrub is and how developed the flower buds are. As a general rule of thumb, we dig in the order that things leaf out. Some varieties can be dug as soon as the ground thaws, but others, like oak, redbud, and birch, will be more successful if you wait for the ground to warm up a little first.
When you take into account all of these time-sensitive factors, along with the unpredictable weather of spring in the Midwest, you can see why the digging window on a lot of items is very small. Since jobs can come up unexpectedly and you may not always know what you need before it’s too late to dig, we stock up our MPC yard with a variety of B&B and Accelerator® container material that can be safely planted throughout the year. Our B&B stock items are wrapped in plastic, fertilized, and drip irrigated, so we are not simply maintaining them, but we are ensuring that they continue to grow and thrive. Our Accelerator® container program was created to allow us to supply field-grown-quality tree and shrub inventory throughout the entire season.
Unfortunately, there is no simple guide that you can consult to tell you which specific days of the year you can dig any given variety of tree. That would make it easier, but plant production just doesn’t work that way. Although the trees leaf out in the same predictable order each year, the amount of time we have before they leaf out is as unpredictable as the weather. Ultimately, like many other aspects of the nursery industry, it takes a combination of traditional knowledge and personal experience to make everything come together.
