Avocado tree roots can invade nearby soil while searching for water and nutrients growing up to 30 feet wide. Plant avocado trees at least 15 feet away from other trees, walls or pavers to prevent any damage. Planting avocado trees in improved, well-draining soil and watering them deeply will encourage a deep strong root system rather than a wide invasive one.
This article will explore all you need to know about avocado roots systems and what to be aware of before you plant a new tree.
9 Avocado root facts to know before you plant
Check out these top facts about avocado roots to know before you plant one in your yard.
1. Avocados have strong root system
Avocados grow a strong root system with most of the roots growing in the top 6 inches of soil. Avocados have been known to have invasive roots so keeping them around 15 feet or 5 meters away from homes or buildings is the best idea.
The root systems can spread beyond the canopy so don’t’ plant them near other trees as they will compete for water and soil and both can suffer.
2. Avocado roots develop near the surface
Avocado roots like to grow near the surface of the soil. Small feeder roots that take up most of the nutrients from the soil will be near the top layers of soil similar to citrus trees.
Taking care when using a rake or spade around the plant is important to avoid damaging these roots, and avoid planting other smaller shrubs or flowers underneath. These can compete for food and water and the avocado can struggle to grow to its full potential.
Top dressing avocado trees with compost is a great idea each spring as the extra nutrients and water holding capacity of the organic matter will help to feed the roots and keep the soil moist.
3. Avocado roots need lots of water
Avocado trees originally came from central America and thrive with regular rain and the water is held near the roots by rotting leaves. Home grown avocados will need lots of water to keep them growing strong.
Subtropical and tropical regions are easier to keep avocados happy due to the high rainfall.
An avocado tree that is regularly watered will have a strong, healthy root system which will spread out and invade nearby soil. A healthy roots system can lift pavers or steppers so keep this in mind when you choose where you plant to plant your avocado tree.
4. Avocado roots need mulch
Avocado roots while healthy, near the surface and spread out will need a good layer of mulch to survive. Fall leaves are a common and useful mulch for avocado trees but can blow around in the wind if they are not composted first.
An easy mulch which will help avocado roots to grow well is a 2-3 inch layer of bark mulch with a mix of leaf matter, stems and bark. This brown and green mix will break down into the soil, feeding the roots and worms.
Soil bacteria will also break down the mulch and release nutrients into the soil for your avocado’s roots.
5. Avocado roots need lots of oxygen
One of the important things to remember about avocado roots is they love water but hate being without oxygen. Overly soggy soil and too much mulch can starve them of oxygen so only layer mulch to a maximum 3 inches thick.
While the avocado roots love water, they hate being wet for a long time as this starve them of oxygen, wash away nutrients and cause root rot. Bark mulch will help to regulate the water in soil as it release and absorbs excess.
Take care with watering and water when the top few inches of soil is dry. Summer rainfall in the tropics is usually enough to keep the avocado trees happy but a dryer winter can call for a water top up from you from your garden hose.
6. Avocado roots need free draining soil
Avocado tree roots hate being wet so planting them in good quality, free draining soil is important. improving the soil with compost first is a great step if you have heavy clay soils or sandy soils where water is lost quickly.
Creating a healthy soil base for your avocado will help its root system to grow to a healthy side, absorb the water it needs, while still getting oxygen. The roots will spread out under the canopy of the tree and deeper down into the soil.
Avocado trees grown in poor, heavy soil will send out their feeder roots beyond the canopy in search of water and nutrients rather than deeper into the soil.
Encourage a deep healthy root system on your avocado tree by preparing the soil first, building it up with organic matter and top dressing with a light layer of compost in the spring.
Check out this quick video of the journey of a Hass avocado from seed to fully developed plant.
7. Avocado roots can grow up to 30 feet deep
Avocado roots will mirror its canopy growing the same width and depth as the width and height of the tree. Therefore a 30 foot avocado tree can have a 30 foot deep root system.
How deep avocado roots grow will depend on the soil and watering schedule. In the best, well draining organic matter rich soil, roots will grow deep and wide to the edge of the tree canopy.
In good quality soil the roots will reach down to reach the water in the deep soil layers growing a strong, balanced root system and allowing it to survive longer without rain.
For trees in poorer soil that only get surface water, they can grow shallow roots systems that reach out beyond the tree canopy. Roots will grow shallow, searching for water and nutrients and can grow very wide into your garden beds.
An avocado tree that is 20 feet wide, ideally will have a 20 feet wide root system to stabilize it. Feeding, watering and mulching this area is important to keep the tree healthy.
8. Avocado roots can be destructive
Avocado root can be a problem if planted near retaining walls, pavers or any building. Healthy avocado roots can spread beyond 30 feet so keep this in mind when you choose where you will plant your tree. While well-constructed retaining walls should hold up to tree roots, it is not worth the risk.
Avocado roots have been know to lift paving that is nearby, affect plants growing under its canopy or other trees that are growing too close to its canopy. Citrus trees for example who also like lots of water and nutrients should be given plenty of room and not planted too close to avocado tree roots.
9. Fully grown avocado trees can grow up to 30 feet tall
Fully grown avocado trees can grow up to 30 feet tall and with a root system the same size. Keep the tree smaller than this by trimming it regularly and keeping the canopy down to a size that you can reach.
Trim excess branches and leaf material in Spring to keep it to the size and shape you want. Growing a smaller or dwarf avocado tree is also a great option as they will be grafted onto smaller root stock and will only grow to around 15 feet at full size but can be pruned to as small as 6 feet.
Are avocado tree roots invasive? | Summary
Avocado roots will invade nearby soil in the search of food and water so keep their area free and let them get the nutrients they need. A healthy tree will grow a root system that mirror its canopy so for a large avocado this means roots can spread up to 30 feet.
Choose a dwarf avocado variety to keep it contained and happy in a smaller yard and water it deeply to encourage deep roots rather than those that stretch wide.
I am an accredited practicing dietitian, experienced gardener and a dedicated cook. I love writing and sharing my experience so you can learn from my successes and mistakes.