For some reason I have had a horrible problem this year with understock suddenly dying. This is happening on my newly grafted trees and on a few 1 yr. grafts from last year. The graft heals, the plant is healthy and normal, and then suddenly the leaves start to wither and you get something that looks like the picture below. You'll notice that the stem starts to turn black from the roots up. Not sure what this could be, but I did notice that the understock I'm getting this year is not from seedlings, but from rooted cuttings. Wonder if that could have something to do with it, since part of the stem is in the soil?
Being rooted cuttings does this mean you didn't pot them up yourself?...wonder if soil could have problems in it.
These came from Heritage Seedlings. They were potted up in soil-less potting mix, which is the same one I've been using, so not sure that would be the issue.
Are you 100% sure the understocks are cuttings? If I had to guess what the one in the picture was, I would have said it was a seedling. Either way, the failures are a good arguement for growing your own understocks for purposes of quality control and adaptation to local climatic conditions.
Should be able to find the thick taproot(or remnants of if they've cut it back)if a seedling.I'm recycling rootstock cuttings for future use but am aware that their root system belies their caliper at first....it's a mystery.
That is one from last year, and it probably is a seedling. I've only had a few of them die. All of this year's are from cuttings, and I've seen perhaps 25% understock death.
Dear me K4 that's a lot of maples lost,I'm so sorry for you.Perhaps you should contact them as you may not be alone in this.
Isn't that root rot? From wiki: "Root rot is a condition found in both indoor and outdoor plants, although more common in indoor plants with poor drainage" It also says that spores can contaminate other plants. I have had 2 or 3 of my grafts die from something similar to what your photo looks like.
Looks like indeed root rot caused by a water mold, perhaps phytopthora. I can't imagine K4 isn't careful with drainage though! @Houzi, I thought palmatums didn't make tap roots. I don't think I've ever seen one. Very sorry to hear about the losses K4. -E
K4 I am disappointed for you. Lots of work to get rootstock failures. Did Heritage make any mention that they would be sending rooted cuttings instead of seedlings? The availability list doesn't seem to ID them as RC. Are you considering growing your own rootstock? I am trying forestry Styroblocks this year. Have about 500 seedlings going in those.
My apologies Emery,perhaps the root doesn't continue growing enough to be classed as a taproot.All I know is all my bareroot rootstocks had a long thick central root which I had to cut back severely to fit into the 11cm pots.
I believe Japanese maples have a taproot when young, at least of sorts. Usually seedlings are grown in a pot which means the main root soon encounters obstruction, and is forced to branch out. I guess Houzi's examples were grown undisturbed out in the open enabling them to continue the downward growth. The growth habit of the roots seems similar to the above ground growth in the way they usually have a dominant single stem/trunk when young, but with age become very much divided and multi-branched.
Interesting, I have not grown seedlings in open ground, so perhaps this is a good theory to explain the differences. Generally palmatums are not known for having a tap root, certainly. I do get young grafts that are on open ground seedling stock, and have noticed that the main root goes quite (more than would fit in a 1 liter pot) deep. Houzi, no need to apologize! :)
I agree with you Maf. Palmatum seedlings that grow naturally in the ground do throw some sort of tap root which is easily seen when I pull them out and repot them to give away, I often have to cut it to fit the tree in a small pot. Gomero
