Red Euc Leaves
The following thread was started by Barrie at Las Palmas Norte on December 28, 2002 at 11:00 pm PST
Barrie, are your eucs in pots or in the ground? if in pots, how long for? are they in a greenhouse? what kind of soil? when was the last time you fertilized them and with what? have they still been making a lot of growth? Does the red show more over the whole plant or as speckles/dots? What species are and are not effected? Might not have any really great answers for you, but at least I could relate if something similar has happened. Strange things especially tend to happen if you leave them out in pots all winter, more for some species than others. Also they just tend to decline very quickly in pots sometimes; if they have been in place for a while the only solution may be to pot them up or plant them out and wait for new growth. I don't really understand these things from a physiological standpoint, but have observed them.
The above followup was added by Ian on December 29, 2002 at 2:49 am PST.
I believe the red foliage is caused a to acidic soil. By throwing a bit of Dolomite lime in the soil and increasing the ph you can correct the problem . I've had it happen to my potted gums over the years. Even the Albizias I grew had the problem. The gums I had stored in the greenhouse at work starting to get blistered. I've also seen this happen before to Eucs. that were stored in a greenhouse. I believe the blistering is caused by to much trapped humidity and poor air circulation. I moved the outdoors a few weeks ago, and all the new foliage coming out looks just fine. By the way, the Neglecta that I got from you looks awesome , and it's still in my greenhouse until spring. Cheers, Joe
The above followup was added by Joe, Salt Spring Island on December 29, 2002 at 3:10 am PST.
Joe-
Thanks for the input. I recall mentioning this problem to you and the Dolomite lime suggestion. I have not tried this yet, but I will experiment on some to see the results. Glad to see that E. neglecta is doing good. They are fabulous trees.
Ian-
The Eucs are a first year seedlings and are in 4" pots. The plants themselves are between 4" and 8" tall. They are now (since late Nov.) in a cold frame (not heated). Soil type is coarse sand, 50% and peat 50%. I've not fertilizer at all, or perhaps very little earlier during the summer. Most likely I used (again if at all) a weak solution, half strength, Miracle Grow. The species in question are E.viminalis, E.cinerea, E.niphophila and E.neglecta. The E. cinerea seem to be holding up the best. All others are mostly solid red to blotchy red and have effected the old and new leaves alike. This began appearing late last summer. They're not dead certainly, but unsightly. Any suggestions are welcome. Thanks Ian.
The above followup was added by Barrie at Las Palmas Norte on December 29, 2002 at 3:42 am PST.
Hmmm, well once again I can't say exactly what the problem is but I can tell you what I would do. It is possible that they are suffering because the soil is not very well aerated and/or they are underfertilized. If you feed them with a lot of N they will make too much top growth, but they do need some. I usually use 5-10-10 on mine. I think the best fix would be to pot them into 1-gallon pots using a more coarse, soil mix and some 5-10-10 fertilizer. Then they will be rooted out and ready to plant in April-May. The old leaves might never get better but at least the new growth should be good. That is why I think you might not have much luck doing anything for them in their current 4" pots.
I wouldn't immediately suspect soil acidity is the problem (I always use peaty soil myself, eucs being quite tolerant of it; and these problems are often more complex), but try liming a few and see what happens.
The above followup was added by Ian on December 30, 2002 at 4:58 pm PST.