Fall may feel like the end of the growing season, but it’s also a great time to plant, transplant, and divide many perennials. From fruit trees to evergreens to flowers and more, fall conditions are ideal for this work. The cool weather is less stressful on new plantings, and there’s still plenty of time for roots to get established before winter sets in. Planting those early spring bloomers in the fall is also the best way to enjoy those amazing displays of beauty first thing in the spring. So whatever your garden goals, now is the perfect time to transplant or plant in your yard before the weather turns. First, let’s explore the differences between planting new plants, transplanting, and dividing.
Fall Planting
Fall is a great time to get deals on potted perennials at the nursery, plus it gives you a head start on spring planting. When you would typically be bringing out your gardening gloves to get spring plants in the ground, your fall-planted plants will already be established and blooming. They'll put on a good deal of growth over the fall and early spring as opposed to their spring-planted counterparts, who will spend a good deal of time at the beginning of the season just getting their roots established. Here are some things to keep in mind when shopping and planting:
By fall, plants are starting to slow down their metabolic processes to conserve energy for dormancy, so you can expect to see leaf color changes and drooping. The trunk and branches should still look healthy and feel supple, though, and not be brittle or dried out. There’s no reason to be concerned with buying plants in this less-than-picture-perfect condition.
Some early spring bloomers may have died down over the summer but still be viable. Examples include bleeding heart and spring bulbs like tulips and daffodils. Like with all plant purchases, check the warranty and hold on to receipts.
One type of plant to avoid purchasing in the fall is ornamental grasses. Most grasses spend their stored energy by the end of summer, so they aren’t able to grow new roots if planted in the fall. The same goes for any grasses already in your yard that you want to divide or transplant - wait until spring to do this job.
Make sure whatever you’re planting is cold hardy in your zone. For fall planting you may even want to play it a bit safe by planting for colder zones than your own. For example, if you’re planting in zone 4, choosing a plant from zone 3 or 2 would almost certainly guarantee success.
Don’t forget that you’ll still need to water your plants. Perhaps not quite as much as you would in other times of the year, but newly planted trees, shrubs, and perennials need deep watering that encourages proper root development regardless of the time of year they’re planted.
Fall Transplanting & Dividing
To transplant is simply to rehome - to move a plant from its current location to a new location. Perhaps your plant isn’t thriving where you planted it, you’ve changed your mind on its location, or you’re getting some divisions from a friend. You can transplant pretty much anything in the fall, with the exception of fall blooming plants. Those should wait to be transplanted until the spring.
Dividing is a task appropriate for herbaceous perennials that are outgrowing themselves. You simply split the plant into smaller sections and proceed like transplanting. More on all of this below…
How to Transplant Trees and Shrubs
Trees with a trunk diameter 1” or less and shrubs less than 3-4 years old should be able to be transplanted without too much risk to the plant. The key to a successful transplant is minimizing shock and keeping as many roots intact as possible. Follow these steps:
Water the tree or bush well the day before transplanting.
To minimize the plant’s time out of the ground, prepare the new hole before digging up the old plant. Dig a hole 1.5-2x as wide as the root ball (see below) and about 18” deep for most trees and shrubs (you may need to back fill a bit to avoid planting too deep).
When digging up the plant, use the plant’s drip line as a guide - however far the branches go out is how wide you should dig. When this is unreasonable/feels like overkill, instead use the rule of thumb: 12” per every 1” width of the trunk (so for a tree with a 1” thick trunk, dig the roots out at a width of 12”). Use a spade to dig vertically. Try not to dig at an angle as you don’t want to move in towards the trunk during this step.
After cutting through the roots, dig a trench on the outside of the circle to help you dig under the root ball. Even with larger trees, most of the root ball should be within 18” of the surface. Work in the trench and under the root ball to remove it.
Hoist the tree/shrub onto a tarp or burlap to assist with moving. This will help prevent the soil from falling off of the roots. Immediately place the tree in its new spot.
When planting, be sure to plant the tree in its new spot at the same depth as it was before. The root flare - the base of the trunk that flares out toward the roots - should be just above soil level. Water well.
Treat your transplant like any new plant and keep it on a good watering schedule to help establish the roots in their new location. 2” per week for new plantings and 1” per week moving forward is sufficient.
How to Transplant and Divide Herbaceous Perennials
Herbaceous perennials are plants that die down to the ground each winter and start over in the spring, unlike woody plants, whose woody growth continues year after year (ie trees and shrubs). Herbaceous perennials are good candidates for fall transplanting or dividing. You can tell it’s time to divide your perennials if they’ve been in the garden for a few years and are producing smaller blooms or developing “bald spots” at the center. Dividing perennials helps to rejuvenate the plant and prevent overcrowding, a problem that is not only unsightly but leads to competition for nutrients and susceptibility to disease. It’s also a great way to get more plants for free!
The directions for transplanting herbaceous perennials are similar to shrubs and trees, but they tend to tolerate a bit more stress to their roots, so you don’t have to be quite as exact. That being said, be generous as you dig and start wider and deeper than you think you need to. As with trees, replant your perennials as quickly as possible in their new location, be careful not to plant too shallow, and water them well.
There is a lot more plant-specific info out there as to the whens and hows of dividing and transplanting herbaceous perennials. For further reading, check out this helpful chart by the University of Minnesota.
Final Tips for Planting and Transplanting Success
Water well. Before even planting in the new location, fill the new hole with water. Once you’ve backfilled the soil, water again until the ground can’t hold anymore water. You don’t want it to be muddy, but you do want the ground to be saturated. Continue to water deeply twice a week for the first few weeks to help those roots get established quickly. Be sure to give new fall plants and transplants a long, deep final watering after the first hard frost to thoroughly soak the soil. Water at the base of your plants, rather than from above, to help protect from any disease or damage.
Plant at the right depth. Planting too deep is a common reason that new and transplanted plants fail to thrive. The top of the root ball should be right at or slightly above the soil line. If you cover the root ball/trunk with too much soil or mulch, the roots can actually be deprived of oxygen, causing them to suffocate and die.
Mulch. A 2'“ layer of mulch will hold in moisture, prevent weeds, and hold in just a bit more warmth in the fall to give those new plants extra time for fall root growth. For both transplants and new plants, wood chip mulch or shredded leaves are good options. Whole leaves or grass clippings can create a smothering mat that prevents air and water exchange with the soil below.
Don’t cut back or prune…yet. Resist the urge to “clean up” in the fall, even as your herbaceous perennials die back. Leaving old plant material adds extra protection against freezing temperatures, and it is also a good practice for protecting pollinator habitats. A good rule of thumb is to wait until Mother’s Day weekend to clean up old plant debris. If new growth is beginning before then, go ahead and remove the dead material, but leave it in a pile until the bugs are out and about. Bagging, mulching or disposing of this material too early kills overwintering pollinators and their eggs. For woody perennials - shrubs and trees - the typical time to prune is late winter, but you should look into the unique needs of each plant.
Now get out there in these last few weeks of perfect weather and enjoy getting your hands dirty - without working up too much of a sweat!