Wednesday 22 February 2017

Grafting out a living

Plant propagation has fascinated me for a long time. Being able to create and cultivate new plant life is a very rewarding practice, much like raising a pet or nurturing children it can be hard work, some trial and error but in the end it's all learning and, pardon the pun, growing.

In particular vegetative propagation has been an area of interest to me. Having the ability to take an already established plant to create a new one is a great way to produce plants for next to nothing, a pretty good deal right? Yes, but only if you're prepared to take a chance and give it a go.

There are four main vegetative forms of propagation:

Cuttings

Snip, snip - Rosemary cuttings are pretty straight
forward and a great plant to have for the chef in your house.


This is generally the most widely used method for professional nurseries and backyard gardeners alike. Ensuring you use freshly collected material, take cuttings of growing plants (tips/shoots) and dip into a rooting hormone (powder or gel), then 'dibble' a hole in a pot full of propagation soil mix. Add cutting to hole and secure by pressing gently down on the soil. Sounds too easy? 

Well that was a pretty basic explanation, of course there is more science to it. There are many variables that can effect the success of cuttings and these will depend on the species you wish to propagate and the environment (soil, moisture etc) in which they will be grown.

The most important factor is not to let the soil dry out, keep the soil moist and it is a good idea to cover the cuttings - either with a plastic drink bottle or plastic bag/cling wrap, this helps retain moisture, humidity and lowers transpiration (loss of moisture through the leaves).

Keep the cuttings out of direct light, in a warm sheltered position and mist with a spray bottle a few times a day. When you notice new growth forming and roots at the bottom of the pot, it's time for them to be transplanted.

For beginners, succulents (or succulent type plants) like Senecio, Pig Face, Sedum or Kalanchoe are a very easy way to start to get the 'feel" for it. Others to try are the native ground cover Myoporum parvifolium, Rosemary varities, Westringia, Callistemon, Duranta, Abelia, & Buxus. Though the possibilities are endless and the more you know, the more you can try.


Division

'Divide & Conquer ' Aggies - tough and
reliable, also very easy to divide.

Ever wondered why so many people had "Agapanthus For Sale" sign's in their front yard?  

Probably one of the easiest ways to make more plant from existing stock, given you have big patch (or pots) to dig and split. Division is more often used for clumping plants like grasses, strappy leaf species or those that grow from the spread of underground root structures like tubers or bulbs. 

The best time for division is when plants are hibernating/dormant or during cooler seasons (usually autumn & winter) to alleviate any losses during transplanting. Got some plants to divide? Grab a shovel, dig them up, tease (or cut) them into small portions and replant - wallah! New plants to enjoy. Same goes with potted clumping plants which need some extra leg room. Make some new plants and share with a friend!


Layering

A not so commonly used method these days but still quite a handy and simple way to make new plants. Layering is primarily used for, but not limited to, climbing or sprawling plants and shrubs. There are a couple of ways layering can be done:

Aerial layering is where a portion of the plant develops aerial roots from the stem nodes while still attached to the main plant, this is the point where the new plant will be created. Thinking of it as doing cuttings but kind of in reverse!

In the bag! Aerial layering allows the 'new' plant to
established while still attached to the 'mother' plant.


Once roots start to form, the area can be covered in hessian or plastic wrap with a soil media added for the roots to develop further. Once happy & healthy they can be cut away from the main plant and transplanted into the ground or a pot. This practice was also know as Marcotting. 

Secondly, there is serpentine layering - for all of you out there with a fear of all things slithering, no it doesn't involve snakes! 
Lay it on me - no snakes were harmed in the layering of this plant.

The stem is usually held in place to the soil (or in a separate pot) nearby with wire or pegs while the roots take anchor. Once roots are established and anchored to the ground, the portion below the point of roots can be cut away and the new plant is born!


Grafting

State of the Union - where two become one.

This method of propagation was the main reason I began this blog. Walking and driving around the suburbs of late,  I have noticed a lot of grafted Eucalyptus flowering brightly. It made me think, isn't it a wonderful thing that somebody took the time to bring the Western Australian flowering gum (Corymbia ficifolia) together with a species (such as the more common C. maculata or Spotted Gum) that has a wider geographical range (soil, climate etc), so we can enjoy the floral display they put on. This is also a great species for the home gardener as it's a small tree and because it flowers so profusely it has a shorter, rounder habit.

Corymbia ficifolia "Wildfire"




Corymbia ficifolia "Summer Beauty"
           

Get to what is grafting I hear you yell, okay calm down you lot! Simply put, it is the tissues of two plants that are joined together, the root stock (bottom) and scion (top), to continue their growth together - kind of a horticultural marriage if you will.

The scion is the part selected for it's desired traits such as fruit or flower production. BUT you cannot just go around grafting plants willy nilly, oh no! You can only graft plants from within the same family of plants.

Grafting is certainly not a new fad, it has been around for 1,000's of years and dates back to 2000 BC where it was first used by the Chinese. Today the principles of grafting remain the same - to produce hardier plants, varieties that have better chance of success with increased growth and yield. 

There are many reasons grafting is advantageous, especially in an agricultural world:
  • Fast tracking fruit production by bypassing the juvenile stage (which occurs typically at 5-9 years);
  • Dwarfing - grafting on to dwarf varieties allows higher planting densities, this is especially important within orchard systems, where high yields (such as stone fruit, citrus, apples etc.) are required;
  • Increasing yields by selecting new and improved varieties then combining them with hardy, traditional species takes care of both the above and below ground vigor;
  • Increasing pest and disease resistance - given the advances in plant breeding nowadays, the better selection of hardier varieties is more accessible. Grafting these onto already established root stock also lowers the need for wholesale replanting where previous varieties have failed;
  • Consistency - grafting allows uniformity. The strongest performers are selected or 'cloned' and the result is identical plants throughout the crop. This alleviates natural variation that can produce weaker plants; and
  • Hardiness - plants once labelled as 'difficult' (sounds a bit like my school reports...) now have had the opportunity to be used in wider applications, the home gardener for example.
In an ornamental sense, grafting has allowed accessibility to a wider range of plants than ever before without the need to turn your garden upside down getting the soil composition right. Those fiddly species can now be used with greater chances of success. It also has allowed new 'forms' of plants to be created - topiary and weeping standards add a focal point to any garden through form, shape and colour.

Prunus 'Snow Fountain' - I wonder how it got that name?

I'll be a bit biased now and go on about the great work grafting has done in the field of Australian native plants. Some of the most beautiful examples of Aussie wildflowers occur in areas with very specific soil and climate types such as Western Australia and South Australia. Many of these plants wouldn't survive long in the home garden outside these regions without a bit of intervention. Many of these "difficult" species tend to have a short shelf life anyway but grafting has also improved their longevity.

Your Highness - a weeping grafted Grevillea Royal Mantle.

One of my all time favourite plants is the Silky Eremophila or Eremophila nivea, it's endemic to Western Australia (and is pretty rare in the wild) so to have any longer term success with this beauty you need to splash out the extra and get a grafted form. In doing so you'll be rewarded with year round colour, from it's woolly silver foliage to its alluring purple flowers.

Silky Smooth - Eremophila nivea in full colour mode.

Grafting can be a little more tricky than the previous propagation methods. It is a lot more involved and does take an ounce of skill. So make sure you start with easy to graft species first. Select the right/best method of grafting for your selected species and invest in the proper equipment to get the job done.

So there you have it, plant propagation - a very interesting subject and a worthy hobby to have a go at if you have the time, space and patience. I think us green thumbs tend to find enough of all those things when it comes to the plants we love. So if you've been thinking about, why not take the plunge, there is heaps of info out there on all the techniques mentioned above. Happy gardening.