Caring for trees is relatively simple as they all prefer aerated soil and nearly all prefer full sun. The best thing you can do for your tree is water it regularly in the weeks after planting and add mulch to improve your soil’s water holding capacity. This will prevent against death by drought – the main cause of tree death.
Trees carry water from the roots upwards through the stem and to the leaves. The water cools the tree down and transfers nutrients and stored sugars. More importantly it’s a key compound in photosynthesis, from which the plant produces its sugars. During times of drought trees can’t absorb water through the roots, so sometimes absorb air. This air can block water flowing up the stems – similar to gas embolism in humans. One study in Nature suggests all trees are sensitive to this, so you can’t be careful enough.
Water, Water, Water
The most important message we wish to convey to our customers is the need to regularly water newly planted trees. Whenever a tree is uprooted, it loses most of its root hairs from which it absorbs much of its water and nutrients. These roots will begin to regrow upon planting, but regeneration can take weeks. A tree is thus temporarily deprived of water – an effect known as transplant shock. To minimise this we recommend you water your tree thoroughly in the weeks after planting.
The next most important message is to use compost, applied as a layer of mulch, to improve your soil’s available water holding capacity. Make the sure mulch doesn’t touch the base of the tree.
Soil is composed of broken down rock and organic matter. Your soil type is determined by the broken down rock’s particle size. Sandy soils are primarily composed of large particles, silt medium-sized particles and clay small particles. These produce different drainage profiles with sandy soils draining faster than clay soils. Loam is composed of about 40% sand, 40% silt and 20% clay and is considered the ideal texture. Chalk and peat soils don’t have specific particle sizes, but are known for being alkali and acidic respectively.
Particle size affects a soil’s drainage profile by affecting permeability – the ease that water can penetrate and pass through soil – which is a function of a soil’s mix of macropores and micropores. Whenever it rains, macro and micro-pores are filled with water. Larger pores drain quickly, smaller pores slowly. Sandy soils are primarily made of macropores and clay micropores. Sandy soils thus drain quickly, but clay soils are vulnerable to being waterlogged, which will deprive a tree of oxygen.
Compost improves clay soil’s drainage as it is lighter than dense clay. It increases the number of macropores, allowing water to drain and preventing suffocation. It also increases the average pore size, which is important as clay soil’s pores are often too small to be utilised by plants.
Compost improves sandy soils as sandy soils suffer from a lack of organic matter. Organic matter is important, as it binds the broken down rock into aggregates, in which there are micropores. Compost thus increases the number of micropores, reducing drainage speed, and improving the water holding capacity.
Studies have shown mulching with compost improves every soil’s available water holding capacity and should be applied as standard.
Caring For Potted Trees
With containers you get to select the soil as well as the mulch.
We recommend you use a mix of compost and garden soil for the best available water-holding capacity. Garden soil will also help introduce useful microorganisms.
It is important to water your potted plants where possible in dry periods. Your plant will only receive as much rainfall as the circumference of the pot. Wide containers are preferred as roots grow horizontally rather than vertically, where aerated soil is found naturally.
Naturally decaying plant matter helps recycle nutrients back into the soil. Containers as isolated environments don’t receive this, so it is important to use fertiliser. Organic fertiliser is recommended as inorganic fertilisers can reduce microorganism abundance.
With containers, using different types of mulch is worth considering and can improve aesthetics. Bark chipping and stones will help maintain moisture.
Collecting fallen leaves is recommended to remove potential vectors of disease. You can compost them and burn infected materials.
Mulch will need replacing every so often.
Jorge works in the Primrose marketing team. He is an avid reader, although struggles to stick to one topic!
His ideal afternoon would involve a long walk, before settling down for scones.
Jorge is a journeyman gardener with experience in growing crops.