Q: Does it really make a difference to your success rate at striking plants if you use rooting powder? What does it do and how do you use it? Jen – Mitchelton
A: You have opened up a ‘Pandora’s box’ with this question, and I am going to stick my neck out on this one. I may quite well receive some flak over what I have to say.
Many people recommend you use rooting powder for virtually every plant, when they write or talk about propagation by striking cuttings. This is not at all necessary!
I am splitting your question up into two parts, referring to rooting powder first:
- Does it (the rooting powder) really make a difference in root formation - YES, it does
- Does it really make a difference to your success rate at striking plants - NO, it doesn’t
These statements may seem somewhat contradictory, BUT please hear me out. I will try and explain this to you in simple terms, without getting technical.
ALL plants need particular hormones to produce roots on cuttings. These hormones are produced naturally by the plants themselves. Cuttings from different plant varieties and species have a different ability to root. They produce different levels of these hormones. Many cuttings root easily, some are difficult to root, and some plants cannot produce roots from cuttings at all. The ‘type’ of cutting used makes a difference, whether it be soft wood, semi-hardwood or hardwood cutting, and this depends on the species of plant being propagated. The time of year you try your hand at propagation also makes a difference. They are all related though, to the particular species of plant being propagated.
The substances in ‘rooting powders’ that assist in root formation are the hormones. These are also marketed in liquid and in gel forms. These hormones are produced artificially to induce rooting in plant cuttings and they are very effective. They certainly do induce quicker and more prolific root growth in cuttings. How do you use these products? Just dip the bottom tip of your cutting in the product (whether powder, liquid or gel) and then stick your cutting in your growing medium.
Using rooting powder is NOT necessary, other than in a very few instances, provided you observe a few rules when striking cuttings. There ARE some plants that are difficult to propagate from cuttings and THESE are the plants that would benefit most from the use of rooting powder. There are some variables to consider; WHAT plant are you trying to propagate, and are you trying to propagate this with soft wood, semi-hardwood or hardwood cuttings? Generally speaking, it is the hardwood cutting that would benefit most from the use of rooting powder. Soft wood and semi-hardwood cuttings generally strike roots quicker, BUT it all comes back to the species of plant being propagated. Also, taking cuttings and propagation of various plants is best done at specific times of the year, depending entirely on the species of plant you are trying to propagate.
Now to the second ‘part’ of your question. There are some general rules that need to be followed when striking cuttings. If these rules are followed, you WILL achieve a high success rate in propagation, whether you use rooting powder or not. The point is you will still need to follow these rules, even if you DO use rooting powder. SO, why use rooting powder in the first place, when it is really not necessary? It is ‘these rules’ that are most important to your success rate.
General rules for propogation with cuttings
- Use the most appropriate type of cutting for that particular plant … i.e. softwood, semi-hardwood or hardwood cutting, whichever has been proven to be most successful over the years. You need to make some inquiries and check this out. The recommended type of cutting for roses, for instance, is ‘semi-hardwood’. Softwood cuttings here (often also referred to as ‘tip cuttings’) will not strike roots, and hardwood cuttings would be very, very slow and difficult. On the other hand if one takes Coleus as another example … all three types of cuttings will strike root fairly easily. The ‘softwood’ cutting will be quickest, then the ‘semi-hardwood cutting’, and the slowest would be the ‘hardwood cutting’
- Propagate at the most appropriate time of the year for that particular species of plant, which has again been observed and proven over the years. Some plants are best ‘struck’ as cuttings in late winter, whilst others do best in spring or even summer
- Preventing the cutting from drying out is THE MOST IMPORTANT aspect of the whole process. You should sit your cuttings in water until you are ready to strike them. The sooner you plant the cutting after you have taken it from the plant, the better
- The higher the humidity around the cuttings, the quicker they will root. There are various methods of doing this. Misting, covering the cuttings will clear plastic material, etc.
- Avoid direct sunlight on the cuttings. That generally spells ‘disaster’
- Keep the planting medium moist … NOT wet, but moist
- Aeration is important. If the cuttings are covered with some material, this needs to be opened up for a short period from time to time. One needs to keep the environment ‘humid’, NOT ‘clammy’
- The planting medium needs to be ‘open’ in structure for best results. Just plain coarse washed river sand is an excellent medium for propagation. Coarse river sand mixed 50:50 with a potting mix or a loamy soil will also give you very good results. There are commercial propagation mixes available in the market, but why buy those when you can make up your own as just suggested!
- Once the cutting has ‘struck’ in sand and has formed a root system, it then needs to be re-potted into a good potting mix
- Cuttings should be taken from healthy plants and not from those that are under any form of stress. ‘The weaker the mother the weaker the child’! The healthier the plant from which you take your cutting, the better its success rate will be
- Light shade is best for most cuttings at the time of propagation. NOT heavy shade, for the more light they get the better. ‘Indirect light’ NOT direct sunlight
- Cuttings strike best if the planting medium is kept warm … and this is particularly so in winter. In late spring and summer there will be no problem, for the ambient temperature will suffice to keep the medium at warm enough levels.
If you follow the above ‘general rules’ of propagation by cuttings, you will achieve excellent results. Rooting powders are not necessary in most instances. Even if you DO use them, you still need to follow the above rules.
