How to graft plants

Crops like tomatoes, aubergines and peppers, plus ornamental trees and shrubs, can be grown from grafted plants. It combines two types of plant to produce a stronger, healthier variety.

Grafting a plant is difficult and needs much practice, but lots of pre-grafted plant options are available to buy.

What is grafting?

With vegetable plants, for example, grafting combines a strong base plant, called the rootstock, with another variety that has great flavour fruits.

The two plants are held together with a clip or tape so that the cell structures can knit. The result is a strong plant, shrub or tree that’s stronger and more resistant to disease.

Advantages of grafting plants

Grafting can produce a fruiting plant in a much shorter time than if it was grown using the original root system.

Ornamental trees and shrubs, too, benefit from a stronger root system and large flowers in a quicker time.

When to graft plants

Early spring’s the optimum time to graft ornamental plants, but autumn is also an option. Fruit trees can be grafted at most times of the year, depending on the variety.

Grafting species

Most plants must be grafted to their own species. Occasionally though, some can be grafted to another species, as long as they come from the same family. Grafting needs practice and often trial and error, so be patient!

How to graft ornamental trees and plants

Side-splicing is a technique that’s usually done at the very end of winter or early spring.

  • Take the top plant, called the scion wood, from a healthy variety that’s between one to two years old.
  • The appropriate pencil-thick rootstock should come from a seedling that’s about two years old.
  • Carefully use a sharp knife for grafting.
  • Above a bud, cut the scion into a 6-10inch (15-25cm) length.
  • Make the rootstock about 3inches (7.5cm) in length.
  • On the rootstock, create a downward nick at about 1inch (2.5cm) from the top.
  • Then, carefully put in a downward cut that slopes to join the first cut. Take out the wood slither.
  • With the scion, perform a cut on one side to match the cut length on the rootstock.
  • Now make a small, angled cut at the scion base.
  • Place the scion base into the rootstock, ensuring the green layer just below the bark meets together.
  • Wrap the graft with grafting tape or strips of polythene. Raffia fibre can also be used for this.
  • Grafting wax can be added to any cut surfaces left exposed.
  • Plant in compost, then water, but don’t overwater. Grow in a greenhouse or propagator if you can.
  • In around eight weeks, new growth should show if the graft has been successful.

How to graft fruit trees

A grafting method called ‘whip and tongue’ is used for fruit and some ornamental grafting plants.

  • Graft around March to early April. Use rootstocks that were planted about 12 months earlier.
  • In December, choose a scion tree with vigorous shoots. Take five to six 9inch (23cm) sections by trimming above a bud each time.
  • Make sure your rootstock and scions are equal diameter, at around 1inch (2.5cm).
  • Group the scions together and ‘heel’ into sheltered, well-drained soil so that 3inches (7.5cm) of the scions remain above the surface. Heeling means placing in the ground temporarily.
  • Before the rootstock buds break around February time, cut the top off at 6-12inches (15-30cm) above surface level and trim any side-shoots.
  • Perform a 1.5inch (3.5cm) sloping upward cut on one side, making sure it exits about halfway through the stem.
  • Now make a downward cut that’s a third way down the exposed side of your first cut. This should be a quarter of an inch (0.5cm) deep to create the ‘tongue’.
  • Take one scion, which is three or four buds in length, and insert a flat sloping cut that’s 2inches (5cm) long. Make this behind a bud.
  • To form the matching tongue, now make an upward cut that’s a quarter-inch (5mm) deep.
  • Bring the pieces together to make an interlocking tongue between scion and rootstock.
  • Merge together as best you can, then apply tape or raffia to bind firmly.
  • After around eight weeks, then scion and rootstock should fuse together, and the tape can be removed.