Leaf scorch isn’t just an issue for hot dry conditions. Recent extreme weather has turned our region into brown crinkly landscape of discoloured and fallen leaves well before our usual autumn. It’s a major bummer for gardeners. As a small silver lining (or perhaps more accurately bronze), it’s also an opportunity to photograph and post about something that often catches folks by surprise: storm wind desiccation damage on plants despite concurrent heavy rainfalls.
What is Leaf Scorch and Why Does it Happen?
- Loosing excessive moisture (heat, low humidity, wind);
- Lacking access to sufficient moisture (drought, erratic watering);
- Unable to take up enough moisture (limited root systems, root damage);
- Unable to effectively distribute moisture (damage, borer, pests), or
- Under a combination of these stresses.
Note: Environmental leaf scorch is not the same issue as bacterial leaf scorch.
What Does it Look Like?
Affected leaves will typically turn brown (or in some cases black) from the tips and margins of the leaf inwards. Where storm wind damage is a factor, the damage will be more extensive on the most exposed areas, and it is not uncommon to see areas of a tree or shrub substantially more damaged than sheltered parts. The sudden degree of damage can be rather shocking.
In our recent example, it was like full autumn (although not quite as colourful) within a few days of the storm. The widespread damage also helped with diagnosis since all of our gardens, parks, and green spaces were suffering degrees of similar damage. At least we can take solace in not being alone!
Protecting Plants from Leaf Scorch
Plant for the Conditions
Provide Shelter and Support
Provide sheltered positions for plants that are vulnerable to wind-related issues. Use frames or stakes to help reduce wind-rocking in young transplants or other shallow rooted specimens. Provide wind breaks, if needed. Relocate portable potted plants to sheltered areas during windstorms.
Keep Plants Healthy and Hydrated
Foster healthy root development and general plant health by planting in well-suited soil and maintain that soil quality over time with amendments if/as needed. Feed, prune, and/or provide other routine care as needed for plant health and keep watch for signs of disease, pests, or other problems.
Take care when digging or doing mechanical work near your plants to reduce the risk of root damage. Beware of water logging, over fertilising, root diseases, and other factors that can cause root damage.
In periods of dryness, where feasible, provide regular deep waterings and use a mulch or groundcover to help retain moisture. Protect plants by ensuring they are well-hydrated before storm winds. This can help to reduce the risk of leaf desiccation as well as the risk of dry and brittle branches breaking.
On smaller plants with a few damaged leaves or wind-battered tips, it may be helpful to nip or prune (depending on the plant). For wide spread damage this is typically unfeasible. Scorched leaves will linger around until their natural cycle to fall; however, heavily affected leaves may drop and regrow or drop prematurely without regrowth if you are approaching natural dormancy.
Do a holistic review of your affected plants. Are there issues with their placement or other conditions that left them vulnerable? If so, you might want to plan transplants at a suitable future point, create additional shelter, and/or adjust their care cycle to try and reduce future vulnerabilities. No matter how careful your planning, planning, or care, it may not be enough to prevent storm damage. Sometimes just things get a little battered no matter what. Nature is a powerful force!
In the examples photographed for this post, the winds that caused the damage came with heavy rain, but not enough to make up for the extreme sustained storm winds. The storm hit at the end of a lovely sunny summer, but that also meant dry conditions. Weather and watering restrictions placed plants in a pre-storm stress position from sustained dehydration. Pampered plants survived with minimal damage (except the ones that cracked off and blew away!), but large trees all around town were heavily scorched and will likely drop a significant portion of leaves before slowly recovering.