Summer Transplanting

Print Friendly, PDF & Email

Making Smooth Summer Moves

I’ve recently been asked to advise on the moving of a long established garden. My first response was to wait until autumn, but sadly, that isn’t possible. Generally speaking, summer transplanting of mature woody plants is not a great idea, especially in years like this one, when weather swings wildly from chilly and damp to hot and dry. You can certainly plant anything you like from a nursery container, from trees to ground covers, as long as you can keep it adequately watered. However, digging up a large established plant and moving it to a new home is a job best left for cool, rainy autumn.

What’s the difference? Even when we are careful, digging a plant for removal inevitably breaks some of the plant’s roots. When the plant is moved, the rootball will be exposed to drying sun and wind. Even if placed in the shade, a rootball will start dying the moment it’s wrenched from the ground. This is true whether the plant was watered before you began digging or was in totally dry soil. As long as the root system was intact, the plant was probably coping adequately with the heat and drought. The minute their roots are damaged, plants go into shock.

Leave The Leaves

Conventional wisdom suggests that removing some or all of a shrub or perennial’s foliage helps transplanting survival rates. That can indeed work when moving a deciduous plant in October or November (which are good times to move plants). In autumn, deciduous plants are entering dormancy and losing their leaves naturally. Removing foliage doesn’t hurt anything at that season, though it’s often best to leave semi-evergreen foliage in place to protect against frosts that could damage a perennial’s crown.

In summer, a new transplant’s damaged roots can’t take up water or nutrients efficiently. The best way for a damaged plant to nourish itself is through the foliage (photosynthesis). With the foliage removed, the plant does not have much ability to restore itself. The good news is that many plants, especially hardy perennials, are pretty tough. If the rootball contains enough stored nutritional reserves, the lucky gardener may see new shoots within 4-6 weeks of the initial trauma. Unfortunately, the damaged plant will be more susceptible to drought, disease and pests than usual for at least a year after the transplanting experience.

Garden Etiquette & Advance Shovel Pruning

The folks who need to transplant their garden are moving to a new homesite. In their case, the new owners of their former home are well aware that the plants are not staying. The beds will be refreshed with new soil but the new owners prefer to make their own plant choices. This is rather unusual, since in general, people are buying the garden setting as much as the house itself. As a point of garden etiquette, it is customary when selling your house to mark any plants you plan to remove so the buyers know your intention. If at all possible, it’s preferable to arrange to make a return visit in fall, after the rains return, so you can move your plants then.

When that won’t work, you can prepare trees and shrubs for a move by shovel-pruning a few months in advance to make the plant more receptive to the later move. Use a sharp-bladed shovel (made extra sharp with a bastard file) to sever the plant’s outermost roots, demarking the rootball you plan to excavate. Don’t rock the plant or disturb the rootball, but do water it well and mulch the rootball area with 2-3 inches of moist compost. This technique encourages new roots to form within the newly formed rootball, closer to the main trunk. A few month’s notice can mean the survival of a plant that otherwise could not take the stress or removal.

Making The Moves

If you must move a plant in high summer, assess whether the plant is worth moving even if it dies. For instance, the most common summer transplanting questions I get concern Japanese maples. These are easily stressed in high summer, when a very hot day can cause the foliage to scorch or curl badly. Expert tree movers with equipment can usually move a maturing tree successfully, but the average amateur is almost certain to kill the tree. As a rule of thumb, if you can dig the tree yourself and move it easily in a wheelbarrow, you can probably move it successfully. If not…probably not. If you feel you must, pre-cut the rootball, then water the plant well every day for at least a week. On a cool day, or early in the morning, transplant it into a large pot (like a whisky barrel), using plenty of compost, and water it well, foliage and all. Use a hand truck to move the tree into the shade and keep it there for at least another week.

Before loading the tree on a truck for relocation, spray the foliage with an anti-dessicant product like Wiltpruf to keep the leaves from losing moisture during the move. Let that dry, then gently bundle up the branches with soft twine. Wrap the foliage loosely but thoroughly with woven row cover cloth (like Reemay) to prevent wind burn. Now load the plant, supporting it well (I use bags of compost or topsoil) to prevent rolling about in the truck bed.

After Care For Transplants

After the move, keep the plant in light shade for at least another week if at all possible. This transitional area should not be in deep, dank, dark shade, where mildews and molds prevail. Try to find a sheltered spot with good air circulation, where the plant receives gentle morning light but no direct afternoon sun. Ideally, you would leave your tree there until the autumn rains return. In October or November, transplant the tree, making sure the new site offers the proper amount of light and plenty of room for the tree to grow to its full mature size.

Again, use plenty of compost when replanting and carefully place the rootball at the same level it was at before. Planted too deeply, even trees can smother. Planted too shallowly, delicate roots can dry out and die. For anything but rhododendrons, azaleas, or blueberries, add a mixed-species mycorrhizal inoculant, placing it so it touches living roots. This beneficial substance will help the plant produce a healthy new root system quickly, often speeding up its recovery time dramatically.

This entry was posted in Garden Prep, Planting & Transplanting, Pruning, Soil and tagged , , , . Bookmark the permalink.

Leave a Reply

Your email address will not be published. Required fields are marked *