How to propagate Magnolia Soulangeana

(Question)

I have a 3 yo Magnolia Soulangeana with a sentimental value. I am moving to another house in the same neighbourhood (High Park) and I would Javi loved to take it with me, but I am afraid to kill her. I am exploring the option to propagate it. How can I go that? Or do you know where to find someone that can do it for me?

(Answer)

It is so hard to leave a beloved tree when you move.  Fortunately there are several techniques which you could try to to propagate your Magnolia Soulangeana (Saucer Magnolia) which might allow you to take a bit of your tree with you.

While it is possible to transplant Magnolia Soulangeana, as your tree is more than three years old and appears to be more than 10″ high, transplanting might be difficult given the complexity of the root system and the size of the root ball that you would need to take with you.  Also transplanting is best done in the dormant season – i.e. late fall or early spring, which might not meet the timing of your move.

However, while not all species, cultivars or hybrids of the genus Magnolia are easy to propagate, the hybrid Magnolia Soulangeana can successfully be propagated by cuttings. There are two methods of propagation that you could try.

The first; and more traditional technique, is air layering.  Air layering is best done during the growing season while the tree is actively producing new growth.  Whether you can try air layering will depend on how long it is until your move (or how accommodating the new owners of your house are) as it may take several months before enough roots develop in the cut stem before you can sever it from your tree. The technique is as follows:

  1. Cut two slits in a a healthy, disease free branch which is at least a year old.  The slits should go upwards go up the stem from the cut be 1/2 to 1/3 inch deep.  You can apply rooting hormone (obtainable at your local garden centre or hardware store) to the open wound.
  2. Wet a handful of spagnum moss, squeezing it out to leave the moss damp.  Wrap the moss around the wound and cover the spagnum moss with a square of plastic film, secured at the top and bottom by with electrical tape or rubber bands – the latter will more easily allow you to open the plastic to water the spagnum moss, if necessary.
  3. Water the moss before it dries out – it will look lighter if it is drying out.   It is important the the moss remain moist, but not soaking wet, at all times as otherwise any developing roots will die.
  4. Once you can see through the plastic that roots have developed, you can completely sever the branch and plant the rooted cutting in a pot or directly in your garden.

The second technique is to take some cuttings from your magnolia and root them. Although propagating magnolia from cuttings is best done with soft wood cuttings in early summer when the new growth is still flexible and not too woody, you can propagate saucer magnolia with semi-ripe cuttings taken in mid-summer.  Semi-ripe cuttings can be taken and are taken from the current year’s growth which has started to mature and become woody at the base while remaining soft and flexible at the tip.  The technique is as follows:

  1. Take a number of 6 to 8 inch cuttings of newly developed shoots, each cut just below a leaf node (the place on the stem where a leaf emerges from the stem), near where the stem is starting to harden, each with a number of leaves attached.  Several cuttings are recommend at this increases the chances that some of your cuttings will establish new roots.  Note that the location of the cut is important as it is at the leaf node that new growth occurs.  Taking the cuttings is best done in the morning before the heat of the day.
  2. Immediately put each cutting in water or wrap the ends in paper towels to conserve moisture, making sure that the end of each cutting is kept moist until it has been planted in the growing medium.
  3. Remove the lower leaves from each cutting, leaving a few leaves at the tip.  Pinch off any still soft growing tip on each cutting.
  4. Make a 2 inch vertical slip in each cutting  – at the cut end  – and dip the cut end in rooting hormone.
  5. Plant each cutting in a pot containing only a well drained sterile rooting medium (i.e. a 50/50 mix of perlite and peat moss or peat moss and sand).  You can place a number of your cuttings in the same pot, provided they are not too close together.
  6. Place the pot(s) in a warm, humid environment out of direct light.  For example you could place them in dome covered flat, or inside zip lock bag, which has not been completely closed.  The aim is to allow for some air movement to reduce the likelihood of disease.
  7. These pots can be taken to your new home.
  8. In 4 to six weeks you should tug on your cuttings to see if they have developed roots (if so there will be resistance when you tug).  This might take longer – i.e. several months or until next spring.  At that point you can transplant your cuttings into bigger pots.
  9. The repotted rooted cuttings can then be placed in a cold frame or nursery bed (in a semi shady spot) until the following spring when you can move the healthiest cutting to its final location.

No matter which technique you decide to try, make sure that your pots and cutting implement are very clean to reduce the change of infection.  Do not over water the air layered site or the cuttings, but do keep them moist.

Below is a link to a more detailed article on growing magnolia trees from cuttings, which you should be useful and informative.

https://www.weekand.com/home-garden/article/grow-magnolia-tree-cutting-18058862.php

Good luck!  I hope you are successful.