Adequate spacing between trees is essential for preventing disease spread and ensuring adequate light levels. Below, we have infographics of many common rootstocks, spaced as closely together as possible. However, you may want to alter your calculations based on such variables as:
- Variety: vigorous varieties (triploids such as Bramley) produce bigger trees and weak-growing varieties (many cider apples) produce smaller trees. +10% and -10% respectively.
- Environment
- Soil: nutrient levels, organisms, pH, texture and structure all affect the eventual size of your tree.
- Nutrients: trees require three main nutrients: nitrogen (N), phosphorus (P) and potassium (K), known as NPK. Deficiencies in any will reduce growth. To address this use organic slow release fertiliser and apply mulch.
- Organisms: soil organisms play a key role in the soil, transforming nutrients into soluble forms, available for uptake by plants. Organism abundance can be promoted by using organic fertiliser and compost, and by forgoing inorganic fertilisers and compaction.
- pH: every species is suited to a specific pH range. pH’s beyond the range will render nutrients unavailable for uptake by plants.
- Texture/Structure: Soil is a mix of broken down rock and organic matter. There are different sized rock particles known as sand, silt and clay with sand being the largest and clay the smallest. The size of the particles affect the drainage properties with the sand draining quickly and clay slowly. Texture is determined by the mix of particles in the soil, producing sand, silt, clay and loam soils. All soils require the application of organic matter to improve their structure, producing the perfect mix of micro and macropores, ensuring water doesn’t drain too quickly or too slowly.
- Exposure: trees exposed to high winds will grow thicker stems to prevent uprooting. Planting in a sheltered spot is recommended.
- Sunlight: fruit trees should always be planted in full sun. If a tree or building blocks out light, you can expect smaller fruits.
- Soil: nutrient levels, organisms, pH, texture and structure all affect the eventual size of your tree.
- Row Spacing: it is common to leave spaces between rows to allow easy access to trees.
- Pollination Partners: it is common for apple orchards to have a crabapple planted as every 6th or 7th tree, planted equidistance. Crabapples can be trained into a narrow pillar shape as all you are interested in is the blossom. Try ‘Evereste’ as an excellent disease resistant pollinator.
Very Dwarfing Rootstocks
It is worth noting that the M27 produces very spindly stems and branches. It requires permanent staking as it is liable to uprooting. If you are interested in aesthetics, choose a semi-vigorous rootstock.
Dwarfing Rootstocks
M9 is the standard cultivar for high-density orchards and is less vulnerable than the M27.
Semi-Dwarfing Rootstocks
Our nurserymen recommend the M26 as the best rootstock for the average garden soil.
Semi-Vigorous Rootstocks
The first free-standing trees that do not need a staking. Trees at this size, may be trained into bushes or standards. Although, it is important to note that the higher the branching starts, the greater the spacing required. It is worth noting that semi-vigorous is bit of a misnomer. Semi-vigorous trees still exert a dwarfing effect, producing a significantly smaller tree than one grown on its own roots.
Larger Semi-Vigorous Rootstocks
Vigorous (Standard) Rootstocks
Standard refers to a tree grown on its own roots. These rootstocks are the closest you’ll get to a tree grown on its own roots in the wild.
It is worth noting that you can fit more trees in a space if you switch to a high-density orchard system. Such systems can fit hundreds of trees per acre, but require expert knowledge to set up and maintain.
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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.