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I keep seeing claims that currant cuttings will "root enthusiastically". I'd love to have another black currant bush or two, but so far I haven't been able to get one to survive. They usually last long enough to drop the original leaves and start growing new ones and new stem, then give up.

Had one in a pot this winter, which survived just about until weather improved enough to consider moving it outside. Frustrating. Brown thumb strikes again...

Any advice would be welcome!

Additional notes: Boston area, climate zone 6. The red currants are quite happy; black seem to be struggling a bit. Russian expatriot tells me I absolutely need to add a white to complete the set.,:-)

  • What's your climate zone? – Wayfaring Stranger Apr 3 '16 at 15:34
  • You might also consider growing from seed. Considering ours spread around the yard like weeds (I'm guessing birds transport them), it might be fairly easy. – Shule Apr 13 '16 at 6:41
  • I haven't yet seen them sprout from dropped fruit, but... – keshlam Apr 13 '16 at 15:18
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It sounds as though you aren't keeping the cutting in a humidity tent. In other words, I think your basic problem is desiccation of the cutting. I've found it convenient to root cuttings in one gallon containers - 1 gallon zip lock bags fit snugly over the top. People frequently make little terrariums by cutting the bottom off 1 liter soft drink plastic bottles. Anything that will make the relative humidity of the air above the cutting stay close to 100% will do the job.

Until the cutting actually has roots, the water in the wood is all the water it has. But leaves take in carbon dioxide for photosynthesis and, in the process, will lose water to the air if its relative humidity is less than 100%. However, the water in the xylem of the cutting is all the water it has until roots have been grown - it is a race to grow roots before it runs out of water.

All the cells of a new leaf (or flower) exist in the bud. The leaf emerges because cells are inflated by the osmotic flow of water into those cells. Expression of new leafs exhausts (or nearly so) the water available in the xylem.

You can instead air layer thicker stems. In this technique you remove a ring of bark (a girdle) and wrap it in a growing medium. The nice aspect of layering is that the clone is supported by the mother plant because the xylem is left in tact. Most commonly the girdle is covered with damp sphagnum and wrapped in plastic, though a pot can be split, fit round the stem and filled with some other growing medium such as pearlite (a bit of sphagnum works to fill the gaps). A pot of medium will need to be watered occasionally, whereas if it is sealed under plastic it will have all the moisture that is needed. Then you just wait until plenty of roots have grown by late summer or early fall, sever just below the girdle, remove the covering, and pot/plant your new clone.

An important tip is that layering most frequently fails because of the growth of residual cambium cells on the xylem (people call it bridging). If you simply let the girdle sit for a day or two before covering it, the residual cambium cells will be desiccated and die. It runs contrary to instinct/intuition, but there is absolutely no reason to be in a rush with layers. Basically, the girdle can be made anytime. Just as buds are swelling is usually a good time - no foliage in the way and the bark peels off easily. Again, just like with cuttings, nothing productive happens until after the foliage is expressed and hardened. You can even wait until after the foliage has hardened to cover the girdle!

  • I'd heard about air-layering but been sorta afraid to try it... Would hitting that with some rooting hormone help or hurt? – keshlam Apr 3 '16 at 5:06
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    Rooting hormone is unnecessary. The foliage above the girdle supplies all the auxin that is necessary. Of course you can dust the upper edge of the girdle with hormone powder when you make it. It will give a little kick start to the process. Don't use anything stronger than 3000ppm IBA or 2000ppm NAA. – Jim Young Apr 3 '16 at 7:39
  • You would probably need to take 3-6 cuttings from non fruiting stems and a proportion of those should survive. When you take your cuttings do you remove some of the foliage to prevent transpiration and water loss? Just leave 3 -5 decent sized leaves to aid photosynthesis, and use advice as above. And yes go for a white current too. – user13638 Apr 5 '16 at 7:00
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Try winter hardwood cuttings instead of softwood summer cuttings. With a little rooting hormone (I like good old dip n grow), and almost no effort, you can get 40-60% survival, which works out pretty well.

I have used 6-8 inch stem cuttings in the past. I've switched to using hardwood cuttings whenever possible because it's so much less work. I use Dirr's reference guide to woody plant propagation to check hormone concentration, can look it up if desired.

Of course this doesn't help until the coming winter, so you can try the softwood this summer.

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