Propagating potentilla from cuttings is really easy to do and when done as softwood cuttings during the late spring early summer they root quite quickly, usually in two to three weeks.
What I am going to show you in this post is propagating potentilla late in the season when the wood is much harder. I am also going to show you hard I am cutting these plants back and why.
But first let me explain the difference between a hardwood cutting and a softwood cutting and knowing when to take cuttings for propagation. Plants leaf out in the spring and immediately start growing, here in northern Ohio that usually happens around the third week of April. Once the plants start to make leaves you should wait about six weeks before you take any cuttings. Why? Because when that new growth first appears it is really soft and too tender to support itself as a cutting.
After about 6 weeks the new growth, often called “wood” when talking about plant propagation, begins to harden off. About 6 weeks into the growing season the wood has usually hardened off just enough that when you take a 4-5″ cutting and stick it in a propagation medium the cutting is just rigid enough to support itself and not wilt and collapse. Cuttings taken from this soft new growth are considered “Softwood Cuttings” because even though the new growth has hardened off a little bit, it is still very soft and pliable. Softwood cuttings usually root much faster than a hardwood cutting, but they are also very fragile and fail easily.
In the nursery business we like softwood cuttings because they are so easy to root and they root very quickly. We also have some special techniques that we use to make this work really well. In my “Plant Propagation Madness” DVD that is part of my “Small Plants, Big Profits from Home” Backyard Growing System I walk you through the step by step process and share all of my secret strategies that allow me to root thousands of softwood cuttings very quickly and easily.
As the growing season goes on the new growth gets harder and harder which is how the plant prepares itself for the comming winter. By fall this new growth is no longer soft and pliable but hard and rigid. It can still be rooted, but because the wood is harder it is much slower to make roots. However, because the wood is hard and rigid it is much more durable and much less likely to fail as a cutting with no roots.
With plant propagation timing is everything. Much more important than technique. In this article I am explain the process for rooting Potentilla, but this same process will work for many, many flowering shrubs as well as evergreens. So let’s talking the timing since that is so important and will start at the beginning of the year so you can understand the process that the plants are going through.
Note to folks in southern states or warmer climates. I am going to describe the process and the seasons for cold climates, but it all still applies to you. It’s just that you folks have a much wider window of opportunity. Your plants are as close to dormant as they’ll get during the winter. But you can do much of this year round. Lucky you!
Propagation from Cuttings in January and February
In January and February plants are dormant. Not much going on and all of the wood on the plants is hard. In January and February you can still do hardwood cuttings and stick them outside in a propagation box like this. I’d prefer to do them early, but you can do them in January and February.
This box is 10″ deep and the bottom is open. 12″ deep is actually better. No bottom, no screen, no burlap in the bottom of the box. The frame just sits on the ground. The box is filled with coarse sand. What sand you buy isn’t all that important but it should be coarse which means larger particles even small pebbles. The sand needs to be coarse so water drains through it easily so the stems of your cuttings don’t rot. The cover is just a wooden frame covered with 4 mill plastic. I then paint the plastic white with latex paint so it reflects the rays of the sun. The box should be in a shady location because you can use this box during the summer months for softwood cuttings, but if direct sun hits the plastic it will get way too hot inside.
Propagation from Cuttings in March, April and May
March, April and May are typically not good months to do propagation from cuttings because the plants are just starting to wake up, they are starting to grow like crazy and the new growth is way too soft to hold up as a cutting without roots. That’s why we wait for the wood to harden off. And when plants are actively growing asking them to make new roots at the same time is just not going to work. If you live in a southern state, zone 7 or higher, you can probably start doing some softwood cuttings in mid May. The rest of us have to wait until at least June 1st.
June, July and August
June, July and August are full speed ahead for making cuttings. The wood is soft and pliable, it roots quickly and easily and as the summer goes on the wood gets harder and harder. If you do cuttings early in the summer and they wilt and fail, try some later in the summer. In the nursery business we like the wood soft and pliable, but it takes a different process to make that work. So for you hobby gardeners, just work with wood that is a little harder.
Flowering shrubs and most deciduous plants respond well when the wood is soft. Evergreens you really should give them a few more weeks to let the wood harden off a little. Usually I don’t do a lot of evergreens until the end of June or early July, but you can do them from then right up until winter.
September, October, November and December
By the time September rolls around plants are starting to get ready for the coming winter. But with many plants you might see some new growth in September and that new growth is perfect for rooting cuttings. As the fall season creeps in the wood really starts to harden off, but that means that getting cuttings to hold up in a propagation box is easier and it’s still a great time to root cuttings. Fall is a great time for home gardeners to do cuttings. It takes longer to get rooting results, but do like I do, just take the cuttings and leave them alone until late spring. You can’t rush the process. Just be patient.
By December the ground is starting to freeze, the sand in the propagation box is starting to freeze but you can still stick cuttings on the days that things are not frozen. The freezing temperatures will not harm your cuttings. Just make sure the sand is moist but not soaking wet through the winter.
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Okay, now back to the propagating Potentilla from cuttings.
I picked up about seven of this scary looking Potentilla plants at a nursery sale. I wanted them for the landscaping at the old house at the nursery, but knew they’d need some serious pruning. So I figured while I was at it I might as well stick the cuttings.
As you can see I cut them back really hard! Why? Because they were out of control and Potentilla is a sun loving plant and I want them nice and full at the bottom and that won’t happen if the bottom of the plant is being shaded by the top of the plant. Had these plants been more aggressively pruned as they were being grown this hard pruning would not have been necessary. However, I always prune my Potentilla fairly hard each fall because they do grow aggressively. So I cut them back in the fall and then just let them grow and flower all summer.
So I cut them back hard and sorted through the branches that I removed and I made up about 350 Potentilla cuttings. Mostly I used the newest growth from the tops of the plants. You can see some of those cuttings at the top of this post.
I dipped the cuttings in a rooting compound. I usually use Wood’s rooting compound because it is sold locally here at a nursery supply company and I can buy it in a pint since I do thousands and thousands and thousands of cuttings. The active ingredients in Wood’s is pretty much identical to Dip n Grow which is easier to find. If all you can find is powder rooting compound that’s fine. They all deliver about the same results. Some people make rooting compound out of willow tea. I prefer to use what professional propagators use.
Do you need rooting compound? No. It helps and it does increase your success on some plants, other plants it makes no difference. I almost always use it because if I am going to take the time to make 350 or 2,000 cuttings I want the odds stacked in my favor.
After dipping my potentilla cuttings I simply stuck them in my plant propagation box that is filled with coarse sand. I watered them in really well making sure the sand is nice and moist, then I closed the lid and called it a day. To prepare the cuttings I simply took mostly tip cuttings, made them about 4″ long, removed the leaves from the bottom half to two thirds of the cuttings and I was done.
I could have waited for a hard freeze and did these cuttings after all of the leaves had fallen off but I want to get these boxes full now while I have the time. The results would have been the same.
Questions or comments? Please post them below. I’m trying really hard to respond to as many of these comments as I can! I enjoy chatting with you folks when I can make the time.