Transplant shock is a combination of three factors. Upon moving a tree or plant, it undergoes:
- a form of physical abuse
- it is reduced in size
- and ends up in a new environment.
Each of these factors contribute to transplant shock.
Let’s take a look at what transplant shock symptoms are, and the three challenges a plant faces: physical damage, downsizing, and new environment.
Symptoms of transplant shock
A plant that was newly dug up and moved from one place to the another may show signs of :
- wilting or falling leaves,
- dying branches,
- abrupt fall of flowers or fruit,
- or it might die altogether.
This is called transplant shock.
When does transplant shock occur?
Transplant shock may occur when:
- transplanting seedlings,
- moving a plant around the garden, or even displacing a plant grown in a container or pot!
- planting a tree or shrub from a garden center,
- to a certain degree, even when simply repotting or topdressing a plant.
It also applies to newly purchased houseplants. These leave the optimized environment of a nursery for a completely different setting: your own house!
Can transplant shock occur without moving the plant?
Actually, although not related directly to transplantation, very similar shock can occur in plants.
New buildings or removal of nearby constructions
- This changes both exposure and wind patterns, which can result in shock to the plant.
- Shade where there wasn’t will stunt growth.
- Sun where there was shade might give the tree sunburn.
This can also happen if a large tree is felled. In forestry, sunburn frequently occurs if clear-cuts are performed with a few trees left behind in full sun.
- When construction comes near roots, damage is almost inevitable.
- Setting up a root barrier or a rhizome trap means cutting large roots off. It’s important to prune accordingly.
Physical abuse – broken branches and roots
Moving a plant cannot be performed without some degree of transplant damage to the plant. Roots, branches and leafage are all affected.
Roots suffer most, and branches are often wounded, too. This is typically caused by cutting roots with the spade, pruning, breakage, parts of the plant dying off due to mishandling, transportation and such.
When roots are exposed to the air, tiny invisible rootlets dry up and die off. Damage starts even within the first minute!
- So haste when the plant root ball is exposed is important,
- but it’s also critical to stay soft-handed.
- Act delicately to avoid creating larger wounds by twisting and bruising the plant.
Being goal-oriented is good, but being careful is good, too!
Downsizing – less roots, less branches
Pruning branches is as important as handling roots
For a transplant to succeed, remove branches and leaves to compensate for loss of roots.
The plant had developed its root system to meet increased circulation of sap, water and nutrients as it grew. All of a sudden, the vessels that channel all these aren’t adapted anymore. Their size isn’t optimized as it used to be. It costs the plant more to shift nutrients around than it used to.
This is the main logic behind the practice of evening out what is removed. If half the root system is lost in the transplant, then it’s important to reduce leafage by half as well.
- It’s important to ensure that the proportion of roots stays relatively the same to that of live branches and leaves.f
Also, remember that the bulk of the “active” roots are around the circumference. Roots around the trunk are still good, but usually they’ve already depleted the soil around them and aren’t as important. When transplanting, they’ll have to start getting to work again, which takes a while!
A new growing environment
In the long run, the most important factor is the change in growing environment. When a plant is displaced, the following usually change radically:
- soil type – even in the same garden, soil may be clay on one side and humus-rich on the other, with “spots” of different soil types embedded.
- drainage – drainage and availability of water differs both because of different soil types and different rainfall patterns (overshadowing trees, differences in gusts of wind, etc…)
- exposure – unless you’re moving from one corner of an open field to another, there will always be a different pattern of exposure to sun and shade.
- companion plants – to a lesser degree, neighboring plants will also influence the newcomer. A relationship is always established between a plant and its neighbors, so having new neighbors influences this, too.
A plant, as it grows, responds intimately to its environment, to “bloom where it is planted“. The shock of change can often be overcome, but in some cases proves too much to cope with, and the plant dies.
Plants vulnerable to transplant shock
Some plants are more at risk of transplant shock than others. This is often related to the nature of their root system.
Trees with shallow root systems
Trees that have shallow, far-reaching root systems have a lot of trouble surviving a transplant.
- This is because almost all of their active roots are lost in the transplant.
- For these, it’s better to dig out a shallower but wider swath of soil.
This type of tree is common along bodies of water. Shallow roots resist root rot better.
Smart tip about reducing transplant shock
A study was conducted on young birch saplings that were transplanted and sugar water. Dousing the soil and watering with sweetened water significantly reduced mortality and transplant shock. Why not try it out for your own shrub transplants? Add a cup and a fourth of sugar to one gallon of water (10 oz per gallon or 70g per liter). Mix well and use for watering for the first season.