Without doubt, November and December 2015 have broken most of the weather records we probably didn’t want breaking for our lawns and gardens, warmest, wettest, windiest, least sun, most consecutive days of rainfall, the list is endless. But even more widespread is the waterlogging that has affected gardens – particularly those on heavy, clay soils – and any garden with naturally wet soil.
The short-term effects of flooding and waterlogging may subside. But for plants and gardens, it is the severe longer-term problems that waterlogging can cause that gardeners need to be aware of. The longer the soil is saturated, the more severe the problems become.
Few garden plants, apart from willows and those such as bog plants that naturally grow in water, can survive prolonged periods of waterlogging. The water replaces the air in the soil and as roots need air to breath, they literally drown, start to rot and die. Above ground, the leaves of affected plants show the first signs of the problem, turning yellow, wilting and dropping prematurely. Such symptoms are similar to those of drought, because the dead roots are unable to take up water.
Other symptoms may include:
- Shoots may start to die back and the plant may start to wilt – a sign that it is short of water, since the damaged or dead roots can’t absorb any from the soil
- Bark may start to peel off stems
- Herbaceous plants may fail to come into growth in spring, or their leaves may open initially but then wilt and die
- Bulbs start to rot and die
- Plants may look stunted with poor, thin growth and, in the worst circumstances, completely die.
The good news is there are several things you can do to help rescue your plants and gardens – both in the short term and more permanently. Once the water has dissipated, plants will hopefully start to revive. Helping to build up the strength of your plants once the water goes down is the best way of rescuing them from these serious problems.
How you can help?
Avoid walking on waterlogged soil – especially heavy clay soils.
As plants start to come into growth, apply a foliar feed, this will help encourage new root growth to replace those killed by the wet conditions.
Feed flowering plants with a season long plant food.
You may need to prune out badly damaged or dead shoots, but wait until May or June at the earliest, as it can take plants this long to show signs of recovery.
Spike the lawn using either a garden fork or, better still, a hollow-tine aerator.
Feed the lawn in both spring and summer to replace lost nutrients.
Where areas of grass have died out, reseed them. We recommend Green Velvet Grass Seed.
This may sound bizarre, but you may have to water plants thoroughly during dry spells following waterlogging, as they will be more susceptible to drought stress due to their reduced and damaged root system.
In the worst circumstances, it’s possible that some established plants will be killed by long-term waterlogging.