Autumn is starting to settle on southern Tasmania. The days are now noticeably shorter, the chickens are laying a few less eggs and we’re preparing for a cold change overnight and a major rain event in the next 24 hours. Fingers crossed, this will fall where it’s needed, fill all our tanks and not do too much damage!
I’ve been run off my feet trying to get as many winter vegetables ready and planted out before it gets really cold but I remembered this morning to keep up with the autumn cuttings! There are three main types of stem cuttings that generally fall into different parts of the year – softwood in spring and summer, semi-hardwood in late summer and autumn and hardwood in late autumn and winter (after leaf drop).
A couple of weeks ago I pruned and thinned out my two Blueberry plants (Vaccinium sp.) that currently live in two tubs. They produced over a kilo of fruit this summer so, in an effort to improve on this crop, I planted approximately 60 small cuttings directly into a nursery flat (tray). Hopefully, I’ll have enough young plants from this to put in a hedge of Blueberries and some to give away to family as presents next xmas.Many people I know, even experienced gardeners, seem to be a little shy about propagating plants from cuttings but once you know what to look for, it’s really quite fun, can save a lot of money and provide gifts for other gardening friends and family. This is also called striking or asexual propagation, and is a much faster way to get new perennials than growing from seed. Unlike seed raising though, there is no genetic diversity – we are taking a piece of the plant, putting it in a growing medium and encouraging the piece to form roots and grow.
Some plants strike more readily than others. For instance, Bay (Laurus nobilis) and many of the most beautiful Australian natives can be notoriously difficult even for the experienced, whereas plants like Sage (Salvia officinalis), the Rosemary forms (Rosmarinus sp.) and even Lavenders (Lavandula sp.) can be really quite easy.
Many professional horticulturists use rooting hormones to dip their cuttings in before planting, and these powders and gels are widely available now to home gardeners. While this can help increase strike rates and give a boost to node and root production on hard to strike plants, they do contain some pretty nasty chemicals. I tend not to use anything except very fresh cutting material and if I really feel it’s warranted, (for Bay trees for instance) I use a tablespoon of unadulterated honey dissolved in a half cup of warm water and dip the cuttings just before planting. When I had access to it, I’ve also used small sticks or bark peelings of Crack Willow (Salix fragilis) – which is a weed in Tasmania – soaked in water overnight. Much safer than commercial chemicals 🙂
The big secret to success is before starting, make sure everything is really clean – the pots or trays you want to use, secateurs (and make sure they’re sharp!), the surface you’re working on and of course, your hands. By the way, because of the spines I wore gloves when doing the berry cuttings and made sure they were very clean too. I use a good quality seed raising mix and usually fill the pots and/or trays with the mix and water it before starting doing the cuttings. And make sure you have labels, a marker or pencil and a something clean to make holes in the mix – this has the delightful name of a “dibble stick”. I use a pH tester that lives in the greenhouse – the metal rod is the perfect size for this job.
Today I did a mixed tray of my favourite Boysenberry, Youngberry and Silvanberry that needed pruning, some very special Lebanese Oregano or Za’atar Leaf (Oreganum syriacum) and my favourite Rosemary form (Rosmarinus officinalis ‘Tuscan Blue’).
Because I was using a mix of pots today, I took a mix of cutting lengths to suit. I start by filling the pots, watering them and using the dibble stick to make a hole in each pot. Then I went out and trimmed back the first plant I wanted to propagate, the Boysenberry.
First, make a diagonal cut just below a leaf. This little lump is called a node and is a “hot spot” for potential root growth in the soon-to-be new plant. Next, make a clean cut four or five nodes above my first diagonal cut and, leaving the top for the moment, carefully trim the leaves off the two or three nodes in between, making sure to trim as close to the stem as possible. It should look something like this little Boysenberry below :
Sometimes, if the top leaves are particularly big they might need to be clipped in half too. Carefully put the cutting into a prepared pot and very gently press the soil around the stem. Continue until you’ve got what you need, label immediately and water lightly – a mist bottle is great for this!
This time of the year when there’s still some warmth in the sun, I leave them in a mostly shady spot in the greenhouse, down the bottom of one of my shelves. You can create a mini greenhouse, using a plastic bag with a few holes poked in it if you’re doing a tray inside.
Do you propagate your own plants? What are your top tips for success and best plants? Leave a comment below.