‘Water is life’s matter and matrix, mother and medium.
There is no life without water.’
Albert Szent-Gyorgyi, MD – Discovered Vitamin C
According to figures from the Met Office, the UK had around a third less rainfall last month than its average for April, with southern areas especially dry, with just 36% of its average rainfall, as high pressure dominated for much of the time. The UK continues the recent trend of dry Aprils in recent years, with an average of 48.9mm falling; this is just 68% of the long-term average.
Watering Newly Planted Trees – How Much, How Often?
Watering is one of the fundamentals of successful tree (and shrub) establishment. Trees will require watering for the first two years post planting, after which they will generally be able to look after themselves.
How much and how often to water a newly planted tree will depend on numerous factors including soil type, location, size, species and stage of growth, season and weather (rainfall, hours of sunshine, temperature, wind and humidity).
Soil type – the amount of water in a soil can vary based on the texture and extent of its organic matter; a soil with a high organic content has a greater ability to store water. Plants cannot extract every drop of water from soil and some soils may still feel damp even though plants have started to wilt. This tends to happen in clay soil. A clay soil can hold more water than a sandy soil, but plants are able to extract more water from sand than clay. In contrast, sandy soil can feel dry even though there may be moisture still available to plant roots. Sandy soils tend to need smaller amounts of more frequent watering than clay. Caring for your soil by adding organic matter will improve its water holding capacity.
Location – whether the plant is growing with root restriction e.g. within a pot, or next to a wall. A large plant in a small pot will need more frequent watering than one planted in a border. In a border, the roots are free to draw moisture from a much larger volume of soil than if the roots are confined in a pot. Plants that are pot-bound (i.e. have more roots than compost in the pot) dry out particularly quickly.
Size, species and stage of growth – the larger and more leaves a plant has, the more water it is likely to lose, and the more nutrients are needed to grow flowers and fruit. These are mainly taken up through the roots, dissolved in water, so more water is generally needed to produce flowers and fruit.
Season and weather (e.g. rainfall, hours of sunshine, temperature, wind and humidity) – will affect the rate of water use.
The following is a good general guide as to how much and how often to water your newly planted tree:
- ‘Water in’ when planted
- Continuously water from bud burst in spring to leaf fall in autumn (for deciduous trees)
- Use a watering can with a rose attachment to water or a sprinkler or other such method that will administer water slowly and at a low pressure, mimicking rainfall
- Apply water to the surface of the tree planting pit, evenly distributed over the whole area to encourage even root development
It is occasionally necessary to water evergreens during the winter months if it is particularly dry. This does not need to be done routinely and can be a response to a period of dry weather.
During the height of summer, water should be applied at a rate of 20 litres (roughly 2 x 5-gallon buckets) every other day. A lesser volume water is generally required during spring and autumn.
Top Tips to Make the Most of your Watering
Quantify how much water you are applying to your tree, and how often you are applying it. If there is a problem with watering, it is much easier to diagnose if you know how much and how often.
Mulch your tree. Mulch should consist of either sheet material or organic material and be 1.0m in diameter with the tree at the centre. If using organic material, it should be at least 50mm in depth but no more than 100mm in depth. Mulch should only be applied to the root system; tree stems should be mulch free. The mulch should resemble a shallow bowl not a flat plate. The mulch helps to retain water, prevent weed growth, control soil temperature, and gives you an indication of where you need to water!
NB newly planted trees still need watering, even after it has been raining! It is the root-ball of the tree that needs watering and often rainfall is intercepted by the canopy and does not reach the planting pit.