Propagating Tree Collards from Cuttings
Starting a new tree collard plant can be very easy. Here in the San Francisco Bay Area we usually have mild, wet winters. During the winter we can often stick a fresh tree collard cutting in the ground and come back in a few months to find a healthy new tree collard plant growing. If you just ordered tree collard cuttings in the mail, you’ll probably want to give your new plants a bit more care and attention than that. We have put together a simple guide to make sure that your collards get off to a great start.
The basic steps for rooting a tree collard are: take a cutting, place it in a container with a growing medium, keep the soil moist, and wait patiently for your new plant to grow.
Below is a video we did on propagating tree collards from cuttings, followed by a more detailed written explanation.
Take a cutting
You will want to take your cuttings from fresh growth on an existing tree collard. Cuttings from older growth that has become woody can be stunted and less vigorous. It is usually best to cut off most of the leaves. Leaves help create sugars for a plant to grow, so they can speed up the rooting process. However, they also respire a fair amount of water. Thus, especially in warm times of the year, it is usually best to remove most leaves while your cutting is growing its new roots. You can even remove ALL of the leaves and your tree collard should still root just fine. If you receive a cutting with damaged leaves, don’t worry, the cutting should be just fine. If you receive a cutting from a friend and it is very leafy… you’ll probably want to remove most of the leaves except for just a few at the top. It is fine if a cutting isn’t particularly straight, you can just bury the curly part. You will probably want a cutting that is at least four to six inches long.
Here are a couple examples of how we like to prepare our cuttings. We leave a small leaf or two on top to speed things up but take off the lower leaves to reduce water loss and stress on the plant.
Place your cutting in a growing medium
We suggest using an old one gallon sized nursery container (interestingly a ‘one gallon’ nursery pot usually only holds three quarts of soil… that is a topic for another time). If you don’t have one of these lying around another alternative is to poke holes in the bottom of a large yogurt or coffee container or something similar. Plenty of holes on the bottom is critical. Otherwise the water won’t drain quickly enough and your cutting may rot.
We recommend that you fill the container will a high quality potting soil. You can also use perlite, vermiculite, sand mixed with some compost, or even garden soil. Perlite tends to drain too quickly, and it doesn’t have any nutrients in it once your cutting puts out roots. Garden soil on the other hand can be very ‘heavy’ and not drain very well in a nursery can. A good potting soil will hold on to a lot of water but will still drain well. If you are on a very tight budget, try using garden soil that is very high in organic matter (for example, collect soil from under a pile of rotting branches and leaves). Bury the cutting two thirds or even further in your growing medium. In very hot climates you will want to just have the leaves and an inch or so of the stalk exposed.
Here is our cutting from above placed in an old ‘one gallon’ nursery can with potting soil.
Keep the cutting moist but not waterlogged
The two key ingredients are moisture and sunlight. During a hot time of year you’ll want to place your cutting somewhere shady that is protected from the heat. It is important that it get at least some sunlight though- it will die without any sunlight. During cooler months shade isn’t as critical, in fact your plant will root faster in the sun as long as it doesn’t get too hot and dry out. Tree collards can tolerate some freezing weather, but it is best to protect your cuttings from hard freezes until they have roots and are planted in the ground. In warm times of year you’ll want to water your cutting at least once a day, maybe more if it’s very hot. Some people suggest putting a plastic bag over the cutting to help keep it humid. With this technique you run the risk of overheating and cooking your plant. We don’t recommend using a plastic bag. Also, don’t try to root your cutting in pure water. This works for plants like mint, but will rot your tree collard plant.
Besides keeping the soil around your cutting moist, you should leave it alone. Don’t pull it out to check for roots. They might be there… and you might break them off when you’re trying to check on them. Wait for you tree collard to start growing new leaves. We’ll post a picture of our tree collard cutting from the example above when it has more leaves to give you an example of when it will be ready to plant out. Once your tree collard plant have a fair amount of new growth and you can perhaps see a couple roots poking out your pot’s drainage holes, you’ll know it’s time to plant it in the garden. Three to six weeks is a fairly common wait time, though it can take longer.