3.6 Growing herbs from cuttings.
> Has anyone ever tried to root lavender before? I am trying it and I'm not quite sure if I'm doing it right. I have taken long woody stems from my outdoor plant and have placed them in damp sand in potting pots indoors. I believe I am just to keep the soil moist, is this correct? Also, how long should it take before roots develope and I am able to transplant them?
From ceci.lysator.liu.se (Ceci Henningsson):
This is something about lavender that I wrote for rec.gardens some time ago. It works well with most herbs. For particularly watery-stemmed plants (think impatiens) putting them in a jar with water, like you describe works well. If you add just a teeny-weeny pinch of rooting hormone to the water, you'll be surprised at how quickly the cuttings develop lots of roots.
Lavender is one of the easiest plants (along with fuchsias) to take cuttings from, so it's a good idea to start with them if you're not familiar with the technique.
In addition to what you do, I do the following: I take fairly new stems and pinch out the flower buds. New stems root easier than older, woodier stems. For this reason cuttings are often taken in spring when there are lots of new stems. If your cuttings fail now, try again in spring. (Disregard that if you're in the southern hemisphere.) The reason I pinch out the buds, is that I want the plant-to-be to concentrate on making roots, not on flowering and setting seed. I cut the stem from the plant just above a leaf pair, and then I cut the stem just below a leaf pair. It may seem wasteful to throw a large portion of the stem in the compost, but it won't grow any roots anyway (or at least not as easily as the part just below the leaves). I also remove the leaves below soil level.
Start by watering the growing medium. I usually water it so that water comes out at the bottom. That means it is fairly wet. Then I level the surface before coming back to the cutting. I use what my local nursery sells as "sowing soil". It is potting soil with 1/3 sand added.
Before I insert the stem into the growing medium, I dip the lower part (the one that will be below the surface) in a rooting hormone, that will aid the formation of roots. If you don't have any rooting hormone at home, you can get it at your garden center. It doesn't cost much, and lasts a lifetime, so it's really a cheap investment. Because you now have the powder on the stem, you can't just push the stem into the growing medium, or you will rub off the powder. Instead you poke a hole into it, and insert the stem. Make sure there is contact between the stem and the growing medium. That is called "firming in". Then I take a clear polythene bag, cut a few small holes into it and put it over the pot. Place the pots in the shade. Too much sun and heat will dry out the plants before they have formed any roots to take up water with. Rooting usually takes a few weeks.
Some general advice:
- Think about hygiene. This is something to do on the clean kitchen counter, rather than on the lawn, because you want to introduce as few germs and fungus spores as possible. Since soil and plant material from the garden carries a lot of microbes which are harmful to people (tetanus and parasite eggs for instance), it's vital for your health that you clean the counter afterwards. If you have a greenhouse or potting shed you can do this in, that's probably the best place.
- Check on the cuttings from time to time. They won't need any water for the first few weeks until they have formed roots if you have them under plastic bags. You can see that roots have formed when there's new (light-green) growth on the cuttings. Have patience and don't put them in the garden at once. They need to be a bit more established first. I suggest that, depending on the size of the pot you're using and how exposed to sun and winds the site is, to wait for maybe 1 month after new growth is showing before planting out.
- Place as few cuttings as possible in each pot. That way, if you get a fungus infection in one pot, the whole lot won't be ruined. Also, use small pots. Soil that is not "used" by roots has a tendency to get stale, and that's something you have to avoid here.
- When planting out, remember that lavender plants get quite big, although the cuttings seem tiny. I know from experience that it's easy to be tempted into putting them quite close to each other.
This is getting to sound quite complicated, though, in real life, it isn't. I've taken maybe 10 lavender cuttings at 3 occassions, and none of them failed. Lavender cuttings seem particularly tough. Some times I've been convinced that they had died when they were bone-dry, but they've always come back to life with the help of some water.