Understanding Grafted Plants and Rootstocks

Understanding Grafted Plants and Rootstocks

grated tree

Many types of today's fruiting and flowering trees and shrubs have been grafted. As are many Shade and Ornamental trees, Evergreens, some Grapes, and some Roses are grafted onto rootstock.

Why are so many plants grafted, what are the benefits, and what exactly is rootstock?

grafted fruit tree

Why Are Trees and Shrubs Grafted?

Specific cultivars of our favorite trees and shrubs are grafted as either a single bud or as a scion, onto a compatible root system so they can successfully be cloned. Grafting a new root system, called the rootstock, is done so there is perfect consistency across the board.

Unlike seeds and plants on their own roots -where there is often quite a bit of variety in flower color, size, shape, resistances, life span, fruiting vigor, or fruit quality/quantity. Grafted plants have so many incredible qualities you may not even realize!

6 benefits of grafting

Benefits of Grafting:

  • Grafted plants mature plant faster and in some cases flower and fruit earlier
  • Propagate by cloning uniform crops of specific cultivars at the nursery
  • Perfectly recreating certain benefits and resistances consistently 
  • Improved resistance, fruit, flowers, drought tolerance & cold hardiness
  • Ensuring virus-free material and virus-resistant rootstock
  • Dwarf, Semi-dwarf & compact varieties
  • Larger flowers or fruit
  • Grafted trees may produce fruit at an earlier age
  • Some plants are difficult to root or grow from seed but readily propagate via grafting
  • More variety in a larger climate range
  • Increased Vigor

Grafting takes the benefits of one plant and fuses them onto the roots of another plant that’s closely related. The cons of grafting are only the lingering stigma these plants carry as being ‘weaker’ and breaking easily, and the lingering fear of contaminated source material - which these days is no longer the case!

What Are They Grafted Onto?

Like us when receiving a blood transfusion or organ transplant - it has to be a compatible match! So, Cherry tree cultivars must be grafted onto Cherry tree rootstock, Oranges to Citrus, Roses to Roses, and Apples to Apples.

This process allows growers to cherry-pick specific traits and qualities from both the root and the bud while maintaining consistency throughout an entire crop. Simultaneously removing problems or negative traits that some varieties may carry and preventing them from passing on undesirable traits like thorns, or bitterness.

What Is The Rootstock Or Understock?

It all starts with quality rootstock, also known as understock, which is simply the roots of the plant chosen for the specific traits and qualities the source tree has. Once joined, these traits are then passed onto the grafted, above-ground portion we see - called the scion (a small branch), or it can be just a single bud! This allows many grafted plants to be created from a small amount of source material.

rose tree

There are many types of rootstock available and rootstocks used may change by the region where the plants are being produced for (increased disease resistance or better tolerances for that region). Sometimes they are changed based simply on availability for that particular year.

A few plants need something called an Interstock which is like a go-between that joins the scion and the rootstock. A few tree Roses have interstocks (one for the roots, another for the trunk, and then top grafted rose selection on top) that help plants that may not be completely compatible with each other to be solidly joined together and grow stronger. Like rootstocks, interstocks can impart further benefits to both the rootstock and scions alike.

Once grafted together, the graft union grows to be less obvious over time and the two parts seamlessly become one.

Modern cultivars and grafted plants won’t come true from seed and can be propagated by way of grafting to ensure you are getting the exact same plant every time. These specific cultivars (the combining of the words - cultivated and variety) have to be grafted or rooted. Many tree cultivars and fruits will not be able to be rooted on their own, so they must be grafted.

Once the living portion of the plant tissue, called the cambium layer (which is just under the bark) from the bud or scion is aligned with its rootstock, the roots begin pushing nutrients and plant hormones into the graft to heal the wound and fuse the two together and make them both grow.

Types of Grafting

grafting fruit tree

Grafting can be traced back 4,000 years to ancient China and Mesopotamia! Today's modern nursery experts employ a wide variety of propagation techniques depending on the desired outcome and type of source material they are using. 

While most fruit trees are grafted using a T-Budding graft, other types of grafting include cleft, side-veneer, bark, chip, bridge, saddle, inarch, whip and tongue, and splice grafting.

Grafting Examples

honeycrisp apple tree

Let’s say you want to grow a Honeycrisp Apple tree. You can’t just plant a seed from a Honeycrisp Apple as it will not have the same traits or DNA when it is grown from seed, and you might get one of its parent plants from the past. The same goes for a Bartlett Pear, a Bing Cherry, or other selected varieties of fruiting and flowering plants.

Standard trees (native, ‘own-root’, or heirloom varieties) all can grow very large - sometimes 20-50 feet large! But they can also benefit from being grafted onto rootstock. Some understock used to grow standard-sized Apples for example include Domestic Apple seedlings, Antonovka, or M25.

Rootstock can precisely change the ultimate mature size of the tree. With the Honeycrisp Apple for instance - A Honeycrisp is a Honeycrisp no matter which rootstock it is grafted onto - but different rootstocks can alter just how big that Honeycrisp will ultimately get.

hand grafting a tree

True Dwarf Apple varieties are typically grafted onto a dwarfing rootstock, maturing at only about 40 percent of the normal size of a Standard Apple. Although the plant stays small, the fruit is the normal size. Note true Dwarf Apple trees will need staking to prevent them from blowing over in the wind as they can’t support the weight of the fruit well with this rootstock. Dwarf fruit trees are used for small spaces and to make harvest easier and typically get 6 - 12 feet tall.

Commonly used Dwarf Apple rootstocks are Bud 9, G.11, G.65, G.41, G.214, and M9-337

Semi-Dwarf trees are a great size if you have a bit more space in your landscape and more than double the harvest of true dwarf plants. Semi-Dwarf Apple rootstock keeps the plants in the 12-20 foot range and prevents them from growing taller for easier to harvest.

Semi-dwarf Apple rootstocks may include EMLA 9, EMLA26, G.30, G.890, G.202, G.935, M7, MM106, and sometimes MM111.

Other Types of Grafted Plants

white rose tree

A Rose Tree-Form can be created by combining a straight Rose stem called the ‘standard’, a rootstock, and a specific variety of Rose shrub together. Creating a topiary or ‘Lollypop’ tree. Many types of Lilac Tree-forms and flowering Cherry trees are also grafted.

Other types of grafted examples are combination trees where multiple types of a tree are grafted together to create unique specimens that can have multiple varieties of fruit like the Espalier Edible Grafted 6-In-One Apple Tree that has 6 fantastic varieties on one trunk!

Grafting on larger more mature trees can also be done to repair damage from physical damage. Like a surgeon replacing a lost limb or organ, tree surgeons and arborists can just attach a new branch where one was lost due to storms or accidents!

Planting and Care of Grafted Trees & Shrubs

planting tree

The graft union should be planted just above ground, and never plant any roots too deep, or too shallow. Look for the root flare, the widest part of the stem just above the root, and find where it either slightly angles away before growing straight again, or bulges at or around ground level. You’ll notice a difference in bark color or texture where the roots and scion meet, identifying the graft joint.

  1. Dig your hole about twice as wide, but the same depth as the current root system
  2. Situate the roots so the graft is just above the ground and the root flare is at ground level
  3. Backfill with native soil and tamp down gently
  4. Water your new plant in very well saturating the soil completely at planting
  5. Add a 3-4 inch thick layer of mulch over the entire root system
  6. Pull the mulch away from touching the trunk and graft union.

Maintain consistent moisture for the first year of the plant's life by checking using the ‘Finger Test’ and checking the soil moisture every day, adding water when needed until the plant is established. That’s it!

Fantastic Grafted Trees

green apple tree

Don’t be leery of grafted trees and shrubs! Grafting or budding is not a bad thing, but a necessary way to propagate many of our favorite trees! They are stronger than you think because of the combined union of two fantastic plant portions, both working together to amplify everything you love about your new plant pet!

There is nothing you need to do beyond water and the same support you’d give to a non-grafted plant, but you will reap all the benefits these fantastic plants offer! It is a good idea to protect the trunks of all young trees from rodents and deer rubbing during the winter months.

Check out all the different grafted and ‘own root’ varieties available at Nature Hills today and get the landscape of your dreams!

Happy Planting!

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