When is the best time to transplant flowers?

Transplanting Perennials

Observe where the stems are, and using a sharp shovel begin making cuts around the plant about 6” from the outside stems (For shrubs, dig as far out as the widest branches reach). Angle the shovel slightly so you are cutting out a slight bowl shape.

Once you’ve gone completely around the plant, use the shovel to lever out the chunk of soil and plant. Small plants may pop out with your first push; larger plants may require that you work around the plant again, gently prying as you go.

If it’s too large to handle easily, carefully transfer the plant to a tarp, empty pot or piece of cardboard to move to the new location. Be careful not to break up the rootball too much.

The hole you dig in the new location should be somewhat wider and the same depth as the rootball you’ve remove. Place the plant in the new location, being sure that the soil level is exactly the same-no deeper or shallower. Backfill the hole, firming the soil slightly.

Water thoroughly, then keep an eye on it for several weeks, watering when the top 2-3” of soil becomes dry.

Many spring- and summer-blooming perennials can also be divided at the same time as they are transplanted, giving you additional plants to spread around in your garden or give away. Plus, some perennials lose their vigor if not divided every few years, resulting in decreased bloom and increased disease problems.

Any perennial that grows and spreads as individual plantlets (black-eyed-Susan, hosta, coreopsis, iris, purple coneflower) is easily divided. Plants that grow from one crown or that have a fleshy taproot (amsonia, Russian sage, poppies, butterfly weed) are more difficult or impossible to divide.

Best Times For Transplanting: When Is A Good Time To Transplant In The Garden

No matter how careful you are to put the right shrub in the right spot, sometimes the placement doesn’t work. Maybe the “dwarf” tree grows too tall. Maybe the bushes behind block out the sun. Whatever the reason, it is transplant time. Transplanting isn’t easy on a tree or shrub, so it’s important to select the optimal time to dig it out. When is a good time to transplant? Opinions differ on the best times for transplanting. Here are some tips on transplanting times for gardeners.

When is a Good Time to Transplant?

Experts agree that fall is one of the best times for transplanting, but spring is also considered good. Each season has advantages that the other lacks.

Many claim that fall is the best time to transplant trees and shrubs. Fall transplants can benefit from the months of cooler, moister weather ahead. Thanks to autumn rains, the plant’s roots get a chance to grow before summer’s heat dries up the earth. Strong roots anchor a new transplant into its new location and help stock up needed nutrients.

Compare this to spring-planted trees that will have few roots out into the yard when summer heat arrives so soon

after planting. You’ll certainly have to irrigate early and often with spring planting. On the other hand, those who consider spring the best time to transplant trees and shrubs note that the new transplants don’t have to deal with winter right away. Trees transplanted in fall must face winter winds and cold temperatures before they get settled in their new location.

When to Move Perennials?

The key to moving perennials is not to choose a bad time. You should never move perennials when they are in flower. Wait at least a few weeks after a plant flowers to pick up the shovel. One rule of thumb is to transplant fall-blooming perennials in spring and spring-flowering perennials in fall.

Don’t transplant perennials where the weather is hot, either. Every time you dig up a plant, it loses some roots. In hot weather, this root deficit may make it impossible for a transplant to cool itself.

The best times for transplanting perennials are the months when the weather is cool. Spring often works well, and fall is one of the transplanting seasons of choice.

Best Time to Transplant Trees and Shrubs

One factor to consider, when you are thinking about the best time for transplanting big plants, is whether you will need to root prune. Root pruning is one way a gardener can help a shrub or tree make up for lost feeder roots that help supply it with nutrients and water.

When you root prune, you cut off the roots a short distance from the trunk in order to allow new groups of feeder roots to form. These roots can be incorporated in the root ball when you move the tree, and provide the tree with new roots in its new destination.

One way to root prune is to use a sharp spade to cut through existing roots in a circle, around the plant. Another is to dig a trench around the plant, cutting the roots as you go.

Transplanting times for gardeners need to take root pruning into account. Generally, it is best to root prune in fall. If you root prune in fall, you should transplant in spring, giving the new roots a chance to get started. If you root prune in spring, transplant in fall.

Every year, every year, there are one or two plants that shamelessly refuse to play ball with my plan. They grow taller than I thought, or bloom earlier than I remember – it’s either that or I am just fickle, because I stand outside and look upon my garden and think, “It would look so much lovelier if that was not right there but a bit further back.”

If I were a more ordered person I would make a list of things to move, but I am not. I figure I’m not the only one, either. So here is a guide to moving something at the wrong time of year.

Plants in flower or about to flower hate being moved. It’s a big no-no in their world. All their resources are going in to producing a flower so they can create seed, not new roots. If you must move a plant in flower, do so only if you can accept that you might make the plant unhappy, and that you’ll need to be around to water regularly until you see signs of new growth.

Moving a plant means breaking roots – usually the fine root hairs that do the job of exploring the soil to find moisture. Firstly, you should water the plant before you move it. Then dig your new hole and fill that with water, right to the top; then wait for it to drain away. If you’ve got time (because you haven’t already dug up the plant), do this a second time. This ensures that the soil around the plant is saturated with moisture, and it helps no end.

Then, carefully dig up the plant, making sure that you support the roots as you go. The soil is wet and heavy, and yanking the plant will tear roots – the more roots that remain unbroken the better.

If you need to move it before the next spot is ready, keep it in a tub trug with a little water and soil at the bottom. It doesn’t want to sit in water, but it wants to rest somewhere moist. Replant it and water it again. It’s all about water at this stage: don’t go for a cup of tea – get straight to watering.

And here’s the rub: you should cut off all the flowers,. They need lots of water to produce nectar, so they are stealing a resource that goes into making new roots. Think of it as gaining some cut flowers for the house.

If you find you don’t get a lot of roots, reduce the top growth of the plant. There needs to be a similar ratio of roots to top growth. The plant may sulk and flop about. Be patient.

The younger the plant, the better it will re-establish. Those with fleshy roots nearly always sulk much more than those without. Perennials are much easier to move than shrubs, which along with trees can only be moved from later autumn to early spring. If there’s a lot of soft growth and these are plants loved by slugs and snails, this can be an issue, as those molluscs will sense the plant is under stress and take a bite.

Add a good layer of garden compost as a mulch around the plant. It will feed the plant as it establishes, and lock in moisture to the soil.

Transplanting Established Trees and Shrubs

Moving established shrubs from one location to another is one method of changing your landscape and saving money at the same time. The job may be intimidating, but good preparation will make the project somewhat easier and less time-consuming. Careful attention to recommended practices (root pruning, methods of digging and root protection) will improve your chances of success in getting a plant off to a good start after you move it.

Root Pruning

Roots of trees and shrubs normally grow well beyond the soil volume that can be moved. To keep most of the roots within a small area, root prune in the spring or fall before transplanting. Plants to be moved in the fall (October or November) should be root pruned in March, and those to be moved in spring (March) should be root pruned in October. Root prune only after leaves have fallen from deciduous plants in fall or before bud break in the spring. Plants may be damaged severely if done at other times. Roots within the pruned area grow many branches and form a strong root system within a confined area. If not root pruned, the plant may die from transplant shock because of root loss.

Before beginning, tie up the branches of low-branched or bushy plants to help avoid injury and keep them out of your way. Heavy twine is usually used, but burlap strips or one-quarter-inch rope is acceptable. Attach the twine to a branch at the base of the plant, wind it around the plant to the top and tie it in a loop.

Begin root pruning by marking a circle the size of the desired ball around the tree or shrub, and then dig a trench just outside the circle. The depth of the trench and diameter of the circle are listed in the tables following the text. (These ball sizes are recommended by the American Association of Nurserymen.) Be careful to separate the topsoil and subsoil so that when you backfill the trench you will replace the subsoil layer first and topsoil on top. After backfilling, water the area to settle the disturbed soil, remove air pockets and provide adequate moisture for new root development. Untie branches after root pruning.

Digging the Plant

Before digging the plant, tie up the branches as for root pruning. Mark a branch that faces north so the plant can be properly oriented when planted. Also, mark the trunk where it meets the soil. When replanting, make sure you plant so that this mark is an inch above the soil line of the planting hole. The plant is now ready to be transplanted.

Shrubs less than 3 feet tall and deciduous trees less than an inch in trunk diameter (measured 6 inches above the ground) may be moved bareroot. “Bareroot” means that most or all of the soil is removed from the roots after digging the plant. You can more easily handle a larger root system with the bareroot method than if you dig a plant with a ball of soil around the roots. Bareroot plants should be planted while they are dormant.

Trees greater than an inch in trunk diameter (measured 6 inches off the ground) and all broadleaf and narrowleaf evergreens should be moved with the soil attached. Ball sizes should always be large enough in diameter and depth to encompass enough of the fibrous and feeding root system to provide for the full recovery of the plant.

Trees that are difficult to move (beech, hickory, sweet gum, hornbeam, sassafras, tupelo, walnut and white oak) need larger root balls than trees that are easy to transplant. Trees growing in loose, well-drained soil, such as a sandy soil, will have more extensive or spreading root systems than trees growing in a hard, poorly drained soil such as tight clay.

The digging operation consists of digging a trench around the plant and removing the soil. The trench should be dug far enough from the plant to preserve a large proportion of the fibrous roots and deep enough to extend below the level of the lateral roots (see tables). If you have root pruned, this trench should be outside the root pruning trench.

Before starting to dig, remove loose soil above the roots. Make a circle around the plant about 12 inches beyond the anticipated diameter of the finished root ball. Cut the roots with a sharp spade, inserting the spade at the marked circle with the backside of the spade facing the plant. Be sure the spade is sharp so the cuts will heal rapidly. Next, dig a trench outside and adjacent to the marked circle.

Plants With Soil Attached: For trees to be moved with the soil attached, trim the ball to the proper size and shape with the spade, keeping the backside of the spade toward the plant. Round off the trimmed ball at the top and taper it inward toward the base. You can avoid loosening the soil around the roots by cutting large roots with hand or lopping shears and small roots with a sharp spade. Next, undercut the ball of soil at an angle of about 45 degrees to loosen the ball from the soil beneath and sever any remaining roots.

To prevent drying, cracking and crumbling of soil, wrap the ball tightly with burlap (balled-and-burlapped). Balls up to 15 inches in diameter can be completely covered with one piece of burlap. Tip the ball to the side and place a piece of rolled burlap under half of the ball. Then tip the ball in the opposite direction and pull the burlap under the other half. Pull the burlap up around the ball and tie diagonal corners together at the top. Secure loose burlap around the base of the trunk with twine, and support the ball by wrapping twine around and under the burlapped ball. You can also protect the root system by placing the soil ball in a pot (balled-and-potted) rather than burlapping.

Balls of soil are heavy and can be difficult to move. A ball of soil 15 inches in diameter and 15 inches deep may weigh 200 pounds or more. Lift a plant with a small ball of soil out of the hole by placing a piece of burlap under the ball and lifting by the four corners of the burlap. Consider hiring a professional arborist or landscape manager to move balls of soil weighing several hundred pounds. They are familiar with the procedures of moving such large balls.

Bareroot Plants: For bareroot transplanting, after digging the trench, wash the soil off the lateral roots with water. This minimizes root injury during soil removal. To provide some protection for roots, move the tree with “semi-bare” roots, leaving some soil clinging to the fibrous roots. This helps the tree recover more rapidly.

When the lateral roots are free of soil, tip the tree to one side to remove the soil under the plant. This should be done gradually to avoid straining or breaking the roots and loosening the bark near the base of the trunk. Cut any taproots or anchor roots that still hold at a depth of 9 to 19 inches. To lift the tree out of the hole, grasp it at the base of the trunk, close to the soil line.

Perhaps the single most important cause of failure with bareroot plants is that the roots dry out. Keep the roots moist in peat moss or wrapped in plastic or wet paper until you are ready to plant. Immediate re-planting is best.

Planting

It is important to prepare the hole properly depending on the method used to dig the plant up. Preparing a hole for a bareroot plant is different from preparing one for a plant with a root ball. Regardless of the type of plant, it is important to have the soil tested well beforehand. If the test indicates a need for phosphorous, add it to the planting hole. Do not add fertilizer containing nitrogen.

Bareroot: Dig the hole for a bareroot plant 50 percent wider than the root system so the roots can be fully expanded and arranged in their natural position. To prevent settling of the plant, leave the center of the bottom portion of the hole higher than the edges. The mound height is determined by placing the plant on the mound so that the marked soil line is an inch above the soil line of the planting hole. As the soil settles over time, the plant will settle so that it will come to rest with the previously marked soil line matching that of the new location. When digging, place the topsoil (the top 6-inch layer) in one pile and the subsoil in another.

Place the plant on the mound and spread the roots in the planting hole. Roots should not be crowded or twisted, or arranged in a circle against the wall of the hole or all in one direction. Roots that have been improperly arranged at planting can result in slow growth or even the death of a tree or shrub after a few years. Be sure that the root collar is no deeper than an inch below the soil surface. If plants are placed too deep, the roots will suffocate from a lack of oxygen.

While holding the tree in the proper position (at the center of the hole, at the proper depth and with the tagged side facing north) add subsoil to the hole, gently working it among the roots and firming with the fingers. After all the subsoil has been put in the hole, water with a half-gallon per square foot for well-drained soil (sandy) or 1 quart per square foot for poorly drained soil (clay). Once the water has drained (settling the soil and eliminating air pockets), add the topsoil. Tamp the soil lightly with your foot, but do not tamp so heavily as to compact the soil. Water again to settle the topsoil.

Balled-&-Burlapped or Balled-&-Potted: Dig a hole for balled plants 50 percent wider than the soil ball. The hole should be just deep enough that the root system is at the same depth it was before it was dug. When digging, place the topsoil (the top 6-inch layer) in one pile and the subsoil in another.Set the plant in the center of the hole (leave the burlap on the rootball if present). Cut any twine or wire supports, peel the burlap off the top and sides of the rootball and lay it in the bottom of the hole. Leave the burlap under the ball, but remove any wire supports (pulling the burlap out may injure plant roots). To fill the hole, add subsoil by gently working it around the soil ball and firming with the fingers. After all the subsoil has been put in the hole, water with a half gallon per square foot for well-drained soil (sandy) or 1 quart per square foot for poorly drained soil (clay). Once the water has drained (settling the soil and eliminating air pockets), add the topsoil. Tamp the soil lightly with your foot, but do not tamp so heavily as to compact the soil. Water again to settle the topsoil.

Watering After Planting

Many plants die from too little or too much water during the first few months after planting. Those in well-drained soil are likely to get too little water, while those in poorly drained soil get too much. The proper frequency and length of watering is rarely the same from one site to the next. Determine when and how much to water by becoming familiar with the characteristics of the planting site. Try to maintain constant moisture (not saturation) of the root ball.

Mulch

Mulch helps conserve moisture in the soil, moderates temperature extremes and reduces weeds. Place 2 to 3 inches of mulch over the soil, pulling it away from the trunk of the plant.

Table 1. Root Ball Sizes for Deciduous Trees

Small Trees
Height (up to 6 feet) Minimum Diameter Ball Depth
2 feet 12 inches 9 inches
3 feet 14 inches 11 inches
4 feet 16 inches 12 inches
5 feet 18 inches 14 inches
Caliper (6 feet and over) Minimum Diameter Ball Depth
¾ inches 18 inches 14 inches
1 inch 20 inches 14 inches
1½ inches 22 inches 15 inches
1¾ inches 24 inches 16 inches
2 inches 28 inches 19 inches
Shade Trees
Caliper Minimum Diameter Ball Depth
½ inches 14 inches 11 inches
¾ inches 16 inches 12 inches
1 inch 18 inches 14 inches
1½ inches 22 inches 15 inches
1¾ inches 24 inches 16 inches
2 inches 28 inches 19 inches

Table 2. Root Ball Sizes for Deciduous Shrubs

Height Minimum Diameter Ball Depth
12 inches 9 inches 7 inches
18 inches 10 inches 8 inches
2 feet 12 inches 9 inches
3 feet 14 inches 11 inches
4 feet 16 inches 12 inches
5feet 18 inches 14 inches
6 feet 20 inches 14 inches
7 feet 22 inches 15 inches

Table 3. Root Ball Sizes for Evergreens

Spreading, Semi-Spreading & Globe (or Dwarf) Types (Broadleaf & Narrowleaf)
Spread Minimum Diameter Ball Depth
9 inches 8 inches 6 inches
12 inches 10 inches 8 inches
18 inches 12 inches 9 inches
2 feet 14 inches 11 inches
2½ feet 16 inches 12 inches
3 feet 18 inches 14 inches
3½ feet 21 inches 14 inches
4 feet 24 inches 16 inches
Cone & Upright Types (Broadleaf & Narrowleaf)
Spread Minimum Diameter Ball Depth
18 inches 12 inches 9 inches
2 feet 14 inches 11 inches
3 feet 16 inches 12 inches
4 feet 20 inches 14 inches
5 feet 22 inches 15 inches
6 feet 24 inches 16 inches
7 feet 27 inches 18 inches
Columnar Types (Narrowleaf)
Spread Minimum Diameter Ball Depth
12 inches 10 inches 8 inches
2 feet 13 inches 10 inches
3 feet 14 inches 11 inches
4 feet 16 inches 12 inches
5 feet 18 inches 14 inches

Agronomic Services — News Release

FOR IMMEDIATE RELEASE
FRIDAY, AUG. 6, 2004

Contact: Brenda Cleveland, agronomist
NCDA&CS Agronomic Division
(919) 733-2655

Tips for transplanting trees and shrubs

RALEIGH — Most gardeners find their enthusiasm for gardening with the warming temperatures, longer days and daffodil blooms of late winter. They may not know that fall is also an excellent time to rejuvenate the home landscape, especially for planting new trees and shrubs.

The cost of buying plants and the effort of digging holes and moving plants from pots to garden are good reasons for wanting to do the job well and be successful on the first try.

One of the best ways to start a landscaping project is to collect soil samples from your flower beds. Soil testing is a free service of the N.C. Department of Agriculture and Consumer Services. Soil test reports provide very practical information about soil pH and nutrient levels as well as recommendations for lime and fertilizer, when needed. To find information on how to collect and submit soil samples, visit the NCDA&CS Agronomic Division Web site www.ncagr.com/agronomi or call (919) 733-2655.

Other important factors that affect plant survival and growth after transplanting include site selection, time of planting, method of planting, soil amendments, water and mulch.

Site selection. Evaluate your site and choose plants that are suited for it. Site-specific items to consider include the amount of shade versus sunlight, the moisture level of the soil, and how exposed or protected the site is. It is also important to choose plants that are hardy in this part of the country. Most of North Carolina is in U.S. Department of Agriculture Hardiness Zones 7a and 7b. When you purchase plants at nurseries and garden centers, look for labels that provide information about these environmental needs.

Time of planting. Fall, late winter and early spring are the best times to transplant trees and shrubs. Roots are active during these periods, and weather is less demanding. Summer is generally the most stressful time to transplant trees and shrubs. Good root activity at the time of transplanting is critical because roots provide the food and water essential to successful establishment and growth.

Method of planting. Loosen roots, but do not shake off all of the potting soil. If roots are potbound (that is, growing around in a tight circle), it may be necessary to clip them so they will grow out normally into the soil. Dig the hole two to three times wider than the plant container but not deeper. Position the plant so the crown—the point where the roots and above-ground portion meet—is right at or just above the soil line. Planting a little high is fine since some sinking typically occurs after transplanting. If any stems are damaged in the process, carefully prune them back.

Soil amendments. Some sites need more than lime and fertilizer to be suitable for planting. Many times during new home development, the topsoil is removed leaving heavy, subsurface clay. The physical properties of a heavy-textured clay or even a light-textured sand are improved by the addition of a soil conditioner, such as well-composted organic matter. Soil amendments are best mixed into soil when an entire bed is being prepared for planting as opposed to an individual hole.

Water. Provide adequate water—but not too much—during the establishment phase. A good way to decide whether to add water is to check the moisture of the soil about two to three inches below the surface. If the soil is dry at that depth, water thoroughly in early morning or late afternoon. Once woody plants are well-established, water only during long periods without rain.

Mulch. Finally, after planting and watering, add some mulch. Mulching helps conserve moisture and reduces extreme temperature fluctuations. Three to four inches of mulch is adequate. Don’t get carried away! Too much mulch can weaken the plants in the long run. Also, be sure to keep mulch a couple of inches away from the crown of each plant.

Once trees and shrubs are successfully transplanted according to these guidelines, follow up every two to three years with a soil test. Periodic soil testing is the best way to keep soil fertility and pH within the desired ranges. For advice on collecting soil samples or interpreting your report, contact your local NCDA&CS regional agronomist. Contact information is available online at www.ncagr.com/agronomi/rahome.htm.

-cs-2,3,4 Last Update August 1, 2007

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