If you’ve ever thought about growing fruit trees, you’ve likely heard about rootstocks. These are the foundation of your tree’s growth and play a massive role in how your tree will behave over time. If you’re feeling confused about rootstock sizes, don’t worry—Garden Ninja is here to break it down for you. Let’s dive in!
Before we get into sizes, let’s quickly cover the basics. Rootstock is the root system of a tree that’s been grafted with the variety (scion) of fruit you want to grow. It’s essentially the “base” of the tree, and it determines many things, like the tree's size, vigour, disease resistance, and lifespan.
The scion (the fruiting or flowering part of the main tree) is grafted onto the rootstock (usually chosen from the same plant family so they bond correctly). i.e. an apple scion will always be grafted onto an apple-compatible rootstock and not one for, say, a Plum tree.
The scion and rootstock create the tree you’ll plant in your garden. The rootstock you choose will shape your tree’s future, so it’s essential to understand how size impacts your tree’s growth.
Below are some newly grafted rootstocks I took. The rootstock is the part on the left, the green wax is where the fruit graft has been spliced together, and the scion is the furthest tip on the right.
Rootstocks are commonly used in many fruit and ornamental trees, along with grapes and roses, to provide specific benefits. The trees that often use rootstocks include:
Rootstocks are widely used in vineyards to improve resistance to pests like Phylloxera.
Maples and Flowering Cherries are occasionally grafted to control size or improve adaptation to soil conditions.
Roses are nearly always grafted onto hardy rootstocks to increase durability and to control size.
Rootstocks are used for various reasons depending on the desired characteristics:
Rootstocks can be chosen for their resistance to soil-borne pests and diseases. For example, apple trees grafted onto resistant rootstocks can better withstand nematodes or fungal diseases.
Rootstocks can influence the overall size of the tree, creating dwarf, semi-dwarf, or standard-sized trees.
This is particularly important for fruit trees, as smaller trees are easier to harvest and maintain.
Rootstocks can boost the vigour of the tree or make it more resilient to environmental stresses like drought, frost, or strong winds.
Rootstocks provide a reliable base for grafting a specific variety (scion) of fruit or ornamental tree. For example, commercial apple varieties are often grafted onto hardy rootstocks that ensure consistent performance.
Certain rootstocks can improve the fruit yield or quality by enhancing nutrient uptake and overall tree health.
Some trees cannot be propagated easily by cuttings or seed. Grafting onto rootstocks is a practical alternative.
Let me explain what the numbers and names mean for rootstocks, remembering that each plant type will have a compatible rootstock that the scion can adhere to and grow from.
M27 – V. Small 1-2m eventual height – Great for pots or patios, always keep staked
M9 – Small 1.8-2.5m eventual height -Very productive, always keep staked
M26 /MM11 / M9– Medium 2-3mt eventual height – Good for bushes or cordons, can be trained as a medium-sized tree
MM106 – Large 2.5-4.5m eventual height – Good sizes tree apple, more drought tolerant due to larger rootstock, fruiting after 3-4 years
MM111 / M25– Large full sized 5m eventual height – Full sized apple tree, drought tolerant and fruits after 4-5 years. Maximum yield.
Pixy - Medium 2-3m tall tree - Best for smaller urban gardens or courtyards.
St Julien - Larger 4-5m tall tree. For larger crops of prunus fruits like plums or damsons.
Quince A - There is just one rootstock that grows to 4m, which is why pears can be fast growers. Quinces, however, are super slow to grow even on the same rootstock.
Colt - 4- 5 meters for a large cherry tree.
Myrobalan - 2-3m tall tree.
Montclare - 2-3m tall tree.
| Fruit Tree Rootstock Size | Ultimate Height |
| M27 | 1.2m |
| M6 | 3m |
| M26 | 2-3m |
| MM106 | 3-4m |
| Colt | 4-5m |
| Pixy | 3m |
| St Julien A | 4m |
| Quince A | 4m |
| Montclare | 3m |
| Myrobalan | 3m |
When it comes to rootstock, size isn’t just about height—it’s about how much space your tree will need, how quickly it’ll grow, and even how soon it will start producing fruit. Here’s the breakdown:
Dwarf rootstocks are like the compact cars of the tree world. They’re ideal for those who don’t have tons of space or want to grow a fruit tree in a pot. These trees tend to have smaller root systems and less overall vigour, but they’ll still produce fruit early in their life. A dwarf apple or cherry tree, for example, can be a showstopper in a small garden.
Dwarf trees often need extra care, especially in terms of support (staking), as they are small in size. Large birds landing on branches or strong winds can damage them. As with all fruit trees yearly pruning to keep them healthy and productive is essential.
If you want the best of both worlds, semi-dwarf rootstocks are your go-to. They’re larger than dwarfs but still manageable, making them great for mid-sized gardens. They’ll give you a healthy, productive tree without completely taking over your yard. Semi-dwarfs also tend to be a bit sturdier in the wind compared to their dwarf cousins.
These trees will need some pruning to maintain shape and maximize fruiting, but overall, they are a bit easier to manage than larger rootstocks as you don't need large ladders to reach the tops.
Standard rootstocks are the big boys on the block. These trees grow to full height and size, meaning they need a lot of space and will take up a lot of room in your garden. They do take a little longer to start fruiting, but they tend to produce more fruit overall once they’re mature. Plus, they often have a stronger, more established root system, which makes them more resistant to drought and soil issues.
If you go with a standard tree, be ready for regular maintenance—these trees are big and will need pruning to stay healthy and productive, so large ladders or platforms will be required for winter pruning. Best saved for the largest gardens with the most experienced gardeners!
No, you need a rootstock that is in the same 'family' as the scion or the graft and union will not take. For instance, apples, pears, and quinces (pome fruits) can all be grafted, but they cannot be grafted onto a cherry (stone fruit) rootstock.
When picking a rootstock size, think about:
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Rootstocks are an ingenious way of controlling the height and vigour of fruit trees and other plants like roses. Developed over hundreds of years, this skill enables us to work with mother nature to become more productive in the garden; as someone who has grafted many trees, it's a wonderful skill to have to experience when buying a grafted tree on a rootstock,
For beginner gardeners, I often recommend starting with a semi-dwarf rootstock. It’s a good compromise between size, fruiting time, and care requirements. But if you’re working with a small space, dwarf rootstocks are an excellent way to go!
Happy planting, and may your garden be overflowing with delicious fruit!
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