Cuttings vs Seeds
Sometimes you just can’t obtain seeds for that particular plant, or you may not have the patience or space to germinate your own seeds. Additionally, due to our climate, some plants never reach maturity and seed-production in the UK, so you have to find another way to expand your collection. As with many tropical plants, Hoya propagation is relatively straightforward and will help you multiply your favourites.
Preserve the Genetics
Importantly, growing from seed can produce wide variation in your offspring (unless you are using F1 seed). When using cuttings of any description, you are effectively creating a clone of the parent plant. As such, the genetic information is identical to the parent and you will have produced an exact genetic copy. This is great for proliferating your prized plants and to create new uniform growing stock.
There are many ways to propagate plants without the need to grow from seed. I will focus on the most common types below, but will add to this section in the near future. Most methods involve taking cuttings, which we will have a closer look at.
Stem Cutting is the method I use most. It is simply cutting off a portion of the stem in order to grow it on. Different plants respond to different cutting techniques at different times of the year.
Cut below a leaf node, or ‘Knuckle’ like in this picture of me taking a Hoya carnosa cutting.
In the picture above, you can see where I cut to take a cuttings from Hoya carnosa. Hoya carnosa is a very easy plant to grow from cuttings, as emerging roots can already be seen on most mature stems. As such, the building blocks are already there for you, and your cutting will root very quickly.
You can take cuttings from Softwood, Greenwood, Semi-ripe and Hardwood Cuttings depending on the season and your plant.
In all cases, however, a few rules apply when taking cuttings:
1. Always take cuttings from healthy stock
2. Always use a clean knife to make your cuts to minimise the risk of infection.
3. Always take cuttings from non-flowering stock. This ensures that your cutting devotes its energy into producing roots, not flowers.
To give you a helping hand, you can easily obtain plants that come in powder or liquid form. These can encourage cuttings to produce roots more quickly and also often contain useful fungicides to help prevent early infections and give you a great chance of success.
Many plants do not need the help of the hormone, but the fungicide is a very useful addition to your cutting. Some people advocate applying cinnamon powder to the wound that the cutting has left behind. Apparently it has antibacterial properties.
Use a Sharp Knife
Using a sharp knife, remove a healthy section of stem from just below a leaf node. Remove all but a few leaves, apply a little rooting hormone to the cut end, and place in a prepared hole in a good cutting compost.
Use good quality Compost mixed with sand or perlite to make sure it is well drained. Keep warm and moist (not wet) and you should see new root growth before too long. New root growth emerges from just below the node and will quickly grow through your compost seeking water and nutrients. When you see roots poking through the pot bottom, you know your plant is ready to move on.
Some plants, such as Begonias and African Violets respond well to leaf cuttings. Take a whole leaf, carefully ‘nick’ the larger leaf veins with a clean sharp knife, and pin it flat to some well-draining compost. Before long, roots will emerge from the calluses formed on the ‘nicked’ veins. New vegetative growth will follow soon and the plantlets can be potted up when large enough to handle.
When taking cuttings from a stem isn’t possible, root cuttings are another alternative.
When plants are dormant it is possible to remove healthy sections of root to be potted on in. Fast-rooters need smaller root cuts, where slow-growers need bigger root cuttings as they hold more food reserves to fuel their new development.
Ideally, pencil thick sections of root should be taken. They are then potted up in well-draining compost so that the top of the root section is level with the soil surface. Make sure you put the root in the right way up!! New growth will appear just below the surface – when the new plant is large enough, transplant it to its new position.
Some herbaceous perennial root cuttings are best laid horizontally and pegged down. These often produce several plantlets which saves you a bit of time and effort!
It is vital that you understand that there are no guarantees when taking cuttings. Some, like Hoya kerrii, respond well to most types of cutting. Hoya kerrii does well from leaf cuttings, as long as you take a bit of stem with the leaf, in my experience. Some Hoyas and other tropical plants can be a lot more difficult. With these, the ‘Trial and Error’ approach works well for me. You will find some cuttings take well in the Spring, whilst others won’t do anything for you until the end of the Summer. Keep trying and you’ll find a formula that works for you and each of your plants.
Avoid Taking Cuttings when your Hoya is Flowering
When a Hoya is flowering, it is pushing all its energy into producing the fantastic blooms we all know and love. In my experience, taking cuttings when a plant is flowering not only stresses your plant out but also means you have a load of cuttings that are all programmed to flower, not to grow roots.
I think it is much better to wait for your Hoya to finish flowering before taking cuttings.
How Many Cuttings Should I Take?
Always take more cuttings than you need. Geraniums, for example, will only provide a 70% success rate even with perfect conditions. Some Hoyas have a near 100% success rate, whilst others are much harder to grow.
Make holes with a pencil, or similar, insert the cuttings and tap the pot to settle the compost around the cuttings.
Make holes in moist, light compost with a pencil or similar, insert the cuttings and tap the pot to settle the compost down.