There are a number of different ways you can propagate plants, but I’ve been doing some layering recently, so that’s what I’m going to share about. Layering is basically when a plant forms roots on stems, distinct from the main root ball. You can do air layering: causing a stem up in the air to create roots by wrapping it in some kind of moist medium and plastic, but the easiest way is layering a stem on the ground. It’s dirt easy. It’s a great way to multiply a plant you’ve already got without having to buy more.
Layering is predominantly a method for shrubs. The plant has to be capable of forming roots on the stems. Basically, you get a stem that is close to the ground and force it to stay in contact with the ground until it has formed enough roots to be cut off from the mother plant. Many plants layer themselves, like my Penstemon ‘Firebird’. Low-growing stems that were kept on the ground by the weight of the plant formed roots just by being in contact with the soil and having enough moisture.
Let’s look at some examples of plants I have layered.
This one was an easy, even lazy layering effort. Since the plant is low-growing and the stems are quite light, I just pushed one down to the ground and mounded some soil and mulch over the middle of it, and it stayed there. Being a spreading plant, it will layer itself over time and is starting to, but I made it go a little faster with just a quick little action. Then I ignored it for a while to let it do its thing. After about two months I checked to see if it had enough roots, which it did, so I cut off the stem below the roots and planted this piece nearby. Because it is a naturally spreading plant that forms roots easily it should be fine to plant rooted pieces straight out, whereas with more upright plants I prefer to pot them up first so they have access to more nutrients in a more sheltered environment.
Hebe pimeleoides ‘Quicksilver’
For this hebe, I chose a low-growing branch and pinned it to the ground with a weed mat pin or tent peg or whatever metal pin-like thing it was that made its way into my potting shed. Anything that will hold it down firmly on the ground for a few months will do. Then I put a bit of soil over the part of the branch that was pinned down. You can do this with many shrubs, just make sure the branch or stem is flexible enough that it’s not going to break when bent down to the ground. Some plants will take longer than others and the rate the roots develop will also depend on the season, weather, etc. Make sure the soil around the branch has adequate moisture, but is not sodden. Otherwise just leave it alone for at least a month. This Hebe pimeleoides ‘Quicksilver’ took two months to grow enough roots for potting up. Check carefully for roots so the branch doesn’t ping upwards, causing root breakage.
Coprosma ‘Pacific Sunset’
I started the layering process for the Coprosma ‘Pacific Sunset’ at the same time as the hebe, but the coprosma took significantly longer to form roots. I pegged down a low branch the same as above and the end result was potting up two rooted pieces after trimming off excess leaves.
Now, before you go propagating any plant, you should always check if it has Plant Variety Rights (PVR). If it’s a pure species, it’s all good. It’s the cultivated varieties, particularly the showy coloured plants, that you need to check. In New Zealand, we can propagate a plant that holds PVR for personal use, but it is illegal to distribute plants or propagation material for commercial use without a license from the rights holder. However, in some countries you may not even be allowed to propagate from these plants at all, so do look up your national Plant Variety Rights or Plant Patents website and check. If the patent has been applied for or granted, it is protected. If the patent has lapsed or been declined, you’re all good. If the plant has a label from a garden centre it should state if it is a protected variety as well. It can be hard to figure out though, as some plants are listed under different names for commercial purposes than the ID name they were given during breeding.
To make things more complicated, trademarks are a different thing again. If a certain plant name is trademarked (TM) you cannot sell the plant under that name. However, if it doesn’t have PVR you can sell the plant under another name.
Coprosma ‘Pacific Sunset’ is a good example to use here. On the label (and a Google search for the plant breeder/marketer) the word ‘Pacific’ has a little ‘TM’ after it, so that word is a trademark. I cannot sell this plant using the word Pacific. But the label also states PPAF – Plant Patent Applied For. I understand this is a US patent, so would only restrict me if the rights holder has also applied for a patent in New Zealand, but until I’ve checked it out more closely, I’ll make sure not to sell any of these. It’s best to check carefully if in doubt, since plants can be sold or described under different names.
All that aside, go and have a look in your garden and see what you could propagate by layering. Any time is a good time for layering, as long as the soil is not too dry. Or flooded. Or if there’s a hurricane.