Fiann Ó Nualláin has advice on making the most of this month to ensure eco-friendly propagation.
August is a great month for propagation. Active growth is still occurring and your plants will be packed with auxins — those plant hormones that stimulate cellular generation and growth, including the capacity to form new roots at nodes and other cutting points.
Auxins naturally accumulate within stems, buds, and root tips. So it doesn’t matter if it’s a softwood, hardwood or root cutting, your plants are primed to root right now.
What is interesting is that we can actually utilise some extra auxins to improve “strike rate”or rooting success. Most commercial rooting powders and gels contain synthetic hormones to trigger quicker rooting. Well, we can make a natural hormone agent at home.
Save a few euro but more importantly save on synthetic chemical manufacture and use, save on plastic containers, save on freight miles, save on a trip to the garden centre, and generally save on contributing to climate chaos.
The trick is to make some “willow water”. Willows are packed with salicylic acid and indolebutyric acid — two hormonal rooting factors and two that easily enough leach out into water.
So we can extract this chemistry into a jam jar of cold or room temp water and use that as our dipping agent for cuttings or we can water in cuttings with the solution. More on how to make in a moment but a little on how it works first.
So indolebutyric acid is the hormone directly or a synthesised version found in proprietary blends — it actively stimulates root growth at the basal tip of your cuttings.
Salicylic acid is also prompting of root activation but its main benefit is triggering “systemic acquired resistance” — that’s a flipping on of a plants natural defence mechanism against bacteria, fungi, and viruses.
The biggest setback in cuttings is susceptibility to fungal and bacterial infection at point of cut or in their growing media. So switching on the cuttings defences greatly improves its survival rate long enough to root and develop and fend for itself.
All salix species — from the dwarf Kilmarnock to the giant Salix babylonica, from the garden grown to the ones populating public parks and along river courses and canal banks — contain these two hormones in abundance.
You may not have the room to grow a willow but there might be in the offing, a forage visit to a nearby spot to harvest some rooting hormones. All you will need to do is secateurs off a skinny stem – the length of your arm will do. Or take a few growing tips the length of your hand — five or so will do it.
You can get your harvest home or what I do is start the process on-site. The procedure is to remove the leaves and chop up the tips or stem down to little finger size, gently crush with a pliers or under the pressure of a hammerhead or heal of shoe and place inside a jam jar, fill with water and lid it.
Sit it in a sunny windowsill for three days and enough phytochemistry will leech into the water to use as a dip for cuttings or a watering solution. You can shake daily.
That said the longer the fingers are left to soak the more phytochemistry they contribute to the water and if you can wait a week you will start to see white sediment or cloudy strands form — this is the good stuff. If you can wait three-four weeks even better.
The cloudier the water the stronger the effect.
Willow water can also be utilised as a pre-germination soak to seeds at time of sowing. It can also be used as a diluted foliar feed to boost sickly plants and help strengthen their defence against pest attack.
When willows themselves come under attack - from pest or pathogen — they waft salicylic acid on the air as a warning system to other willows in the vicinity to toughen up and get ready — to switch on their resistance.
The fabulous thing is many other plants do the same when touched by the salicylic acid. Handy thing to have a jar of, as a sort of flu jab for plants.
Earlier this year I got the opportunity to release a book all about herbal teas and their role in human health.
And it was so hard while writing it to not to be inserting the info on how many of them are beneficial to garden plants.
In relation to the garden, my regular go-to is chamomile tea — it contains sulfur which is both a plant pick-me-up and a natural fungicide — so while it is great for fungal infections on growing plants it has a good role in eco-friendly propagation.
Made hot, chamomile tea can be used to clean seed trays of fungal spores or to pre-water growing media to heat-kill spores and to leave an antifungal residue in advance of later sowing. Safer and more planet conscious than bleach or other sterilising agents.
The quicker those old practices lapse, the better for all — and especially the plants.
A cooled infusion can be sprayed onto sown seed trays and seedlings to prevent damping off and other sowing calamities but it can also be utilised on fresh cuttings to defer potential rooting-point rot or infection.
Make a pot, let it cool, keep in a recycled container or mini watering can and water in whenever you want to sustain moisture levels to the cuttings and newly rooted plants.
Last but not least a seed or a cutting will root into growing media it doesn’t matter if that media is in a plastic tray or a cornflakes box. We can think inside and outside of the box and make gardening an even more eco-friendly activity.
Home propagation is not just more plants, it is more plants filtering carbon and atmospheric toxins — if done with some simple plant chemicals and natural utensils all the better.