By Jay White
After years of talking to people and helping them in their yards, I have learned that many people are afraid to move plants. In fact, a lot of home owners have no idea that most plants can be successfully transplanted. Let me assure you, with a little planning and preparation you can successfully move just about anything. While I have moved a few things that did die, most of the perennials I have moved have done pretty well. In fact, many perennial plants need to be dug up periodically and “moved” in order to thrive (iris is a classic example).
All of the attractive beds at my house are the product of trial and error. Even though I plan my beds and plant selections by drawing little diagrams on graph paper, the resulting beds never look as good in my yard as they do on the paper. So, every fall, I take advantage of the cooler temperatures that autumn brings to correct my landscaping errors. Luckily for me, most perennial plants are pretty adaptable, so I can dig them up and move them around when my landscape plans don’t turn out the way I had hoped.
While aesthetic impact is the main reason I move my perennials, there are several others. I think most of us have, at one time or other, had a plant that grew too big for its space or failed to thrive in the location we selected for it. When this happens I say move it. Life is too short to put up with plants that just don’t look or perform the way you want.
Whether you are dividing a clump of iris or moving an eight-foot-tall crapemyrtle, you need to follow three simple steps to ensure a successful transplant. Before you transplant you need to prepare the plant for the move. Next, you need to carefully and quickly dig up the plant and move it. Finally, once the plant has been moved, you need to give it a little extra TLC to ensure that its roots re-establish themselves as quickly as possible.
Preparing for the Move
Fall is the perfect time for transplanting most perennials in Texas. The general rule for transplanting is to move spring-blooming plants in the fall and fall-blooming plants in the spring. With the exception of some perennial-blooming bulbs, fall is the best time to move most of the perennials in Texas. Trees, shrubs, roses, bulbs, rhizomes, corms and grasses need time to re-establish themselves before the absence of water and abundance of Texas sun endanger recent transplants. That is why the cool days and nights of October and November are best suited for transplanting. The decrease in temperatures and increases in rainfall create a lower stress environment for the plants while they are trying to rebuild the roots that will get them through next summer.
Moving plants successfully is really a game of managing the damage done to the plant’s root system by your shovel. No matter how careful you are, you are going to cut a whole lot of roots when you dig up a plant. They depend on these roots for their survival, so it is important to do everything possible to lessen the shock that is going to occur as soon as your spade slips into the soil at the base of the plant.
Before moving any plant, make sure it is fully hydrated. For grasses, bulbs, rhizomes and corms this can be a good soaking the day before the move. However, larger shrubs and trees will require at least a week of deep watering (unless they are deciduous and have lost all of their leaves). This will ensure the plant has as much water as possible in its tissue before you start severing the roots that it counts on to keep it growing. While you are watering the plant also water the location that will be receiving the transplant.
If you are moving an evergreen, it is a good idea to prune it a bit. Most landscapers recommend removing as much as a third of the top growth. When you cut the roots of an established plant you are causing two problems. First, you are removing a good portion of the root structures that it uses to feed itself. The roots of the established tree grew big enough to support it at its current size. Once you cut those roots for transport, there will not be enough root area available to nourish the entire tree. The second problem is transpiration. Plants need their roots to supply the water that the plant will use to cool itself. Just like us, plants cool themselves by releasing moisture. When you sever a plant’s roots, you are reducing its ability to take up enough water to keep it cool. This is another reason that fall is the best time to transplant. Plants require less water for feeding and transpiration when the weather is cool.
Trees, woody perennials
Once the plants are hydrated, it is time to dig. If possible, do your transplanting in the morning. If the morning is cool and overcast, all the better. Before digging up the tree or shrub, dig the hole where the plant is going. This is important. Once a plant is pulled up from its original location, the roots start to dry out. Having the new hole ready will allow you to decrease the shock of transplanting by allowing you to get the roots back in the ground as quickly as possible.
Believe it or not, there are a lot of theories and opinions about how to dig a hole. The proper way is to ensure the new hole is no deeper than the root ball of the plant you are moving and one and half times as wide as the root ball of the plant you are moving. Unless you are dealing with very heavy clay, there is no need to slope the sides of the hole 45 degrees, but it certainly doesn’t hurt. The one thing you should definitely not do is dig a hole deeper than the root ball and then add in compost or mulch or hay. Adding amendments to the soil changes the way water moves through it. Adding mulch and compost to the soil can make water move through it faster than the roots can use it.
Once the new hole is ready, you can begin to dig up the plant that needs to be relocated. Dig in a manner that keeps the root ball intact. I do this by using my shovel to cut a complete circle into the ground around the plant. For small shrubs, make a circular cut that is 12” to 18” in diameter. For larger trees and shrubs an 18” to 24” diameter cut is sufficient. To make your cut, push the shovel into the ground at an angle toward the plant. This will cut the plant’s roots and help create a bowl shaped root ball for transport.
As you remove the plant from its original location, try to keep this soil intact to protect the roots from exposure. If the plant is small enough, use your shovel and hand to transport the plant and root ball to the new hole. Larger plants may require two people using two shovels to keep the root ball from collapsing.
Plants that are extremely tall or have an extremely heavy root ball require a little forethought. If you plan to move a plant that is this big, make sure you have a lot of help. Before digging, place a large sheet of burlap on the ground. When you lift the plant out of the soil, gently set it on top of the burlap. If you are not going too far with the plant, lift the burlap by the corners and guide the plant to its new location. If you need to move it over some distance, pull the burlap up around the trunk and tie or wire it in place. This will help keep the soil intact during transport. Once you get your “burlapped” transplant to its new location, use the corners to lower it into the hole. After the tree is seated, remove any burlap that will extend out of the filled hole.
Once you have placed the freshly dug perennial in the new hole, make sure the soil level of the original plant matches (or is slightly higher) the soil level of the new location. When the plant is at the proper depth and orientation, it is time to backfill. This is one of the most important steps in the entire process. Roots need to be in contact with soil. The recently dug plant will have hundreds or thousands of tiny, exposed roots. If kept moist, these tiny roots will be the first to start supplying the plant with water and nutrients. They will also be the roots that begin to grow out into the surrounding soil to anchor the plant to its new location.
When backfilling the hole, realize that air pockets dry out and kill tender roots. Make sure that the method you use to backfill removes them. If you are in a light soil (like sand or loam), this is much easier. Simply fill the hole about a third of the way with the soil that you removed (never use compost or other amendments to backfill the hole). Water the soil in well. Allow the soil to settle and then water again. Now fill the hole another third of the way and repeat the watering. Continue adding soil and watering until the existing soil, the fill and the soil of the root ball are at the same level. If you have heavy clay soils, break up all clumps or clots of soil into smaller particles before you begin the backfill. This will greatly decrease the chance of creating an air pocket.
To tamp or not to tamp — that is the question. When backfilling, many people advocate using a shovel handle or other device to “tamp” the soil in around the newly planted perennial. Most experts now agree that this is not a good idea. There is a good chance that the act of “tamping” the soil will damage more roots than the plant will benefit from removing air pockets by tamping. The only exception to this is for heavy soils. If you have a lot of clumps and clots, wet the soil thoroughly and then gently tamp the backfilled soil. Avoid “tamping” the soil on the root ball.
Bulbs, corms, grasses
Bulbs, corms, rhizomes and grasses are my favorite perennials to move. Because they are smaller and lighter than most shrubs and trees, they are so much easier to dig and handle. In addition, moving these clumping perennials will invariably provide you with more plants.
There are several great, perennial grasses that are used in Texas landscapes. One of my favorite is purple fountain grass (Pennisetum setaceum ‘Rubrum’). There are also several varieties of Muhlenbergia (“muhly’s”) and Miscanthus that thrive here.
Over time, grasses will become thick and stop blooming or they will die in the middle of the clump. When this happens, it is time to divide the grass. Before digging up the clump remove all but about six inches of the leaves.
Work your shovel around the clump and lift it out. Then use your shovel or a machete to cut the clump into multiple sections. Once the grass is divided, dig a hole just big enough to hold the root ball and backfill. Grasses should be planted soon after digging. If they are left out in the sun for very long, the roots will dry out and die.
Like grass, irises are so beautiful and easy to grow. Because of this, most gardens in the South have at least one clump of them. In addition to their beauty and carefree nature, they spread with abandon. Like grasses, mature iris will begin to die in the center of the stand. When this happens, dig up the entire stand and start over.
Once you have excavated the rhizomes, separate them and discard any that are damaged. Next, take sharp scissors or shears and remove all but four-to-six inches of the foliage. Just as with larger perennials, cutting iris foliage will allow the plants to use all of the available water and nutrients to create roots. Healthy rhizomes should be planted just under the soil. Do not plant too deep. Rhizomes need only an inch of soil over them.
Unlike grasses and woody perennials, irises do not have to be replanted immediately after digging. When you divide a clump of iris, you will invariably wind up with more rhizomes than are needed to fill the original space. You can store your leftovers for sharing or planting at a later date. Lay your rhizomes out in the sun for a couple of days. Once they have dried, move them to a shady spot (a porch or a garage, for example) and let them continue to cure.
Fall is the best time of the year to move spring-blooming bulbs like narcissus, daffodil and snowflakes (Leucojum). Move these bulbs just as you would iris. Dig them up and divide them. Discard any that are damaged or soft. Replant at a depth of two to three bulb lengths.
Bulbs store incredibly well. If you want to keep some for sharing or later planting, let them dry in the sun for a couple of days. After initial drying, move them into the garage. Bulbs that are dried and properly stored can remain viable for several months.
It would be a shame to do all of the work required to transplant a perennial and then watch the plant die as a result of improper care. Transplanted perennials are very fragile. For the next three or four months after planting, they will need a little extra TLC to help them re-establish in their new location.
Newly transplanted perennials need to be watered when the soil around them is dry. Use your fingers to determine when it is time to water. If you can’t feel moisture at around four inches, give your perennials a drink. Conversely, do not let them dry out completely between waterings. Too little and too much water can both rapidly kill a transplanted perennial.
You can help regulate soil water and temperature with a good layer of mulch. As the temperature begins to drop in the fall, mulch can give that one or two degree increase in soil temperature that will allow roots to keep growing even when air temperatures are too low. Mulch also keeps down weeds that will compete for the water needed by your transplant. At a minimum, place two to four inches of mulch around the base of your plant.
Finally, do not fertilize new transplants. Fertilizer makes the plant build greenery. While the plant is re-establishing, it needs to build roots. Do not apply any fertilizer to fall transplants for three to six months after the move.
I know that in an ideal world we would design a bed, plant it and then enjoy it for all eternity. However, most of us don’t live in that ideal world. If you are not happy with a plant in its current location, or it is not performing the way you expect, wait until fall arrives and move it. The milder fall temperatures put less stress on the plant and provide ample time for the plant to re-root before the cold temperatures of winter kick in. If you take a little care while relocating them, most plants will hardly even realize that they have been moved!