Propagating Your Favourite Shrubs

I read an article the other day about propagating shrubs from  softwood cuttings, which inspired me to have a go.

I have two Sambucus nigras— a ‘Black Lace’ and a ‘Black Beauty’. The ‘Black Beauty’ has been wonderful–dark foliage, a lovely shape, and beautiful umbrella-like pink flowers in the late spring.

‘Black Lace’ should be the same except with lacier leaves, but for me it’s been horrible, shapeless, gangly branches that are more like a climbing rose than a regular shrub, and this year it’s been constantly covered with black aphids–my most detested pest. No amount of blasting with water inhibited them and there weren’t any lady beetle larvae gobbling them up. In the end, I decided it wasn’t worth keeping, so I chopped it down and when I get around to it, I’ll dig up the stump. (Have to admit here that I saw a friend’s ‘Black Lace’ on Saturday and it was  beautiful!)

Now I want another ‘Black Beauty’ to fill the spot. What a perfect time for the inspiration to propagate with softwood cuttings to strike. Thanks Gardener’s World for the tutorial.

So now readers, you get my tutorial: I’m going to try to increase my stock of Sambucus nigra ‘Black Beauty’ and show you the steps as I go along.

1. First problem is finding the softwood cutting. According to the article your cutting should be a non-flowering lateral shoot, this year’s growth, and neither very young nor old enough to be woody. Hmmm, non-flowering. Almost all the branches were flowering branches.

These are the cuttings I’ve chosen, but only one of them is “non-flowering”.

I didn’t spend an awful lot of time examining the branches to find ones that were non-flowering, mainly because every one (but one) looked like the shoot below:

Never mind. I’m going to use them all, and if only one grows roots, all I really need is one. The “softwood” part is a bit subjective: Gardener’s World didn’t define “softwood”, so maybe it’s not critical to get that exactly right. Susan Grillo from Fine Gardening defines softwood as mature enough to snap off when bent over. Too immature and it just bends, and too mature doesn’t snap because it’s too woody. I didn’t really test mine; I think they’re pretty soft, but too bad. The concern with too immature is they don’t have the structure to stay alive long enough to get roots. If mine collapse and rot, I’ll just try again in another month or so.

2. Roots are going to grow from the area just underneath the outermost layer, because that’s where the growth hormone that stimulates root growth lives. So I’m going to do two things: strip the bottom leaves off, leaving a little “wound”, and scrape a little bit of bark at the bottom tip.

3. Next thing is rooting hormone: this is the same hormone that the plant produces naturally, so by applying some, we’re just giving the cuttings a bit of a boost. Sort of like an energy drink.

I’ve read somewhere that rooting hormone (usually in powder form, altho’ mine is a gel) is only fresh for 6 months and after that should be replaced. Mine is at least a couple years old, and doesn’t have an expiry date on it. So I’m using it.

Most package instructions say to dip the cutting in the rooting hormone, but I poured a little into a saucer so that, if there’s some bacterial or fungal contamination, it won’t get into the bottle.

4. Planting: This is the easy bit–well, it’s all been easy, once you know how. Seedling potting mixture, dampened, not drenched, dib some holes with a pencil, tuck in the cuttings.

A couple of things to notice in the picture above: I cut all the leaves in half to reduce the amount of moisture that the leaves breathe out (“transpiration”). But the leaves are still photosynthesizing (making energy from the sunlight), so which does the cutting need more: energy or moisture? Don’t know the answer to that, but almost every source says to cut the leaves in half. So I did.

The other thing to notice is how slumpy the cuttings look. It’s recommended that the cuttings be taken early in the day so they have maximum moisture. I cut mine at 4 pm, at just about the hottest part of the day, just about the hottest weekend we’ve had in this hot dry year. Not optimal. But I’ve heard it said that the best time to do something is when you have the time and inclination. That’s when I had the time and inclination.

But now there’s one last step, and it also has to do with moisture:

Cover the whole pot with a plastic bag, secure with a rubber band, and inflate it with a straw (or put a couple chopsticks in the pot) to keep the bag off the leaves. That maintains  humidity, again helping to prevent the cuttings from drying out before they have a chance to put out roots and begin to fend for themselves.

Now we wait. And watch. I’ll check the potting soil for moisture every few days, look for any fungal growth that would signal the death knell, and then in a few weeks I’ll give a gentle tug on the cuttings to see if they’re growing roots. If there’s resistance, there’s probably roots, so I’ll leave them a little longer until there are roots growing out the bottom holes, and then divide and pot up individually. I’ll keep you posted.