Not sure if this is the right spot for this, but let’s try! I’ve been trying to root some cuttings (rooting cuttings is the hardest part for me!!) and I’ve had a wave of failures, generally one or two a day around the 4 week mark. They get a yellow tinge halfway up the stem, then a couple of days later they go blotchy brown. When I pull them, they have a nice callus, but failed to move beyond that. Any advice would be appreciated. Them dying in the middle first is what gets me.
Tell us a little about your procedure and climate.
Warm season cuttings require a somewhat different approach to fall cuttings. Don’t try to callous them. These “semi-ripe” (neither woody nor succulent) cuttings seem to do best when taken from a stem that has just flowered (as it presumably has stores in place for developing hips). Strip ⅔ of leaves and reduce size remaining leaves to a couple leaflets. Stick in well-drained medium – only slightly moist, not wet. Continue to a provide filtered light.
Growth in first two weeks is likely a bad sign as the cutting hasn’t gotten the memo it needs to make roots. This can be due to soil being too moist, and cutting typically fails and succombs to bacteria.
Leaves may drop – not a bad thing; abscissing is an active process of healthy, live tissues responding to stress. (The thing is stressed, and needs to know to respond appropriately!)
After 2+ weeks (depending on size of cutting and temps) new growth more likely indicates successful rooting.
All my cuttings have been from recently flowered stems, first thing in the morning. I cut off the spent flower head and strip all but a couple of small leaves at the very top. Dip in clonex gel rooting hormone and stick in damp, coarse sand. They are placed in a bin, kept indoors at 76 degrees near a bright window. I open the bin twice a day for air exchange. I was keeping it humid enough that condensation would bead on the sides, but not so humid that it would drip. The leaves all dropped within days. No signs of new growth at any point on those that have failed. The yellowing in the middle of the stem, subsequent browning and failure started at the three week mark and extended nearly to the five week mark. Most of the cuttings that failed had a callus.
I would personally recommend placing them into water to callus first without any hormone, and then stick them in a just-moist medium to root (up to half sand is probably fine if your sand is free of impurities*, but the other half should probably consist of organic matter like peat moss). Your light levels could also be inadequate, so consider using artificial light if tweaking the mix alone doesn’t improve your results.
*I’ve had trouble with sand apparently containing salt where I live now; it is rarely beneficial to use such sand in significant quantities for horticultural purposes. If you don’t or can’t know whether the sand you have been using might be behind the problem, try substituting something else for drainage instead.
Stefan
For whatever reason, rooting hormone has done nore harm than help for my warm weather cuttings. (It works well for callousing dormant cutting in e.g. fridge in winter.) And placing cuttings in water for more than a day or two for me personally has generally resulted in failure…
If you are in a humid climate, you might try rooting outdoors in summer warmth.
Philip, do you happen to have fairly alkaline water in your area? Kim has pointed out that it can cause difficulty with water callusing; for me, water pH up to slightly alkaline has never been a problem. See:
Not overly so. Texas hill country is generally faitly alkaline, and my water sure isn’t soft, but such was also my experience in New Orleans with cuttings. God knows what was in that water though. The Mississippi river was the source for drinking water. I have heard it called the intestinal tract of the US, and we were on the parting end, so…