Advice: Is my Serissa diseased?

I bought a Serissa (believe it to be foetida... it smells when pruned) a couple days ago from a nursery. Despite its being moved home in a cold climate, it seems to have coped well with the initial shock, so far. A few leaves have turned yellow (with dark green tips) and then fallen both today and yesterday. It looks quite healthy, however - by my amateur opinion. What concerns me is the base of the trunk. When I bought it, I noticed the trunk was greenish and a bit soft/flaky. Concerned, I asked the shop owner what this was - she said it was just moss, and that it would come right off and I shouldn't worry. On further inspection, it would seem this moss has grown under the bark of the tree at the base. Root structures have grown through the moss (removed in the picture), and these roots seem to belong to the tree itself. I would very much appreciate your advice. Is this a threat to the health of the tree? What should I do to help the tree? I don't want to shock the exposed roots coming off the trunk. Is this tree more prone to infection, having part of the bark gone?

Oh, more information relevant to the yellowing leaves. I already mentioned it is a cold climate here. I am using a humidity tray to regulate the humidity to 50-60%. I keep it by a west-facing windowsill at day with a 60W grow bulb, and close the very well insulated blinds at night. The temperature shouldn't drop below... say 60 F. Daily temperature ranges from 60-70 F. My watering schedule is 2x a week, tops - however, only if the soil is near dry. I feed every other week. It gets a full day of winter sunlight, supplemented with a grow bulb, from noon till bedtime (often quite late for me). I have not pruned at all or repotted - it is still in its plastic dish and the store's bonsai soil. Does that sound like an appropriate plan for care of the tree? Oh, and those serissa flowers are starting to develop. Looking forward to that, unless my tree decides to throw a climatic fit. Anyway, I greatly appreciate your time and help, thanks.

IMAGE LINK:
http://forums2.gardenweb.com/forums/load/bonsai/exch1212260223632.html

The link to that post on gardenweb is actually THIS

Here is the pic anyway:

Whereabouts in the USA are you please?

Fiona:

I live in Indiana. USDA Plant Hardiness Zone is 5b/6a. And yes, thank you. That is my plant. I'll fix that link.

Your tree sounds to be as healthy as you can expect a newly moved Serissa (and foetida is the ONLY species in the Genus) to be.

However, the lower trunk has been damaged by the moss that once grew around it. The damage probably is not life threatening, but the perpetually-wet moss has rotted much of the bark and created some reverse taper in the trunk. It is going to be hard to fix. You might want to encourage any higher root formation and then plant this tree a bit deeper in the soil when the weather warms up significantly.

JimLewis:

I was thinking about building up the soil around those roots before repotting. On the healthy (bark covered side) of the Serissa, there are some nice aerial roots. In terms of aesthetics (perhaps I will have to bury these aerial roots), would it work to have this backside mound of soil covering the damaged side, while leaving the front exposed? Or perhaps I could somehow work this into a root-over-rock design? In the meantime, I didn't want to shock the plant with newly exposed roots, so I plastic wrapped the damaged area. Let me know if I should not do this. I should also mention that I will have to move this plant once again, when I return to college (1.5 hrs) in January. Indoor temperature should be similar. Thanks everyone, for your help.

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I was thinking something like this. I like the mound look it has.

You can mound the soil up and let roots grow until they reach the soil level in the pot and thicken up some, then remove the soil and it will improve the look of the damaged area. Serissas have very thin bark and moss will damage them very quickly, so keep it from growing back. I would lose the humidy tray, they don't do much to raise the humidity.

It is hard to tell from the photo, but is the tree planted in bonsai soil (free draining), or just potting soil? If it is in potting soil, it will need to be repotted as so as it is time into some better soil. Serissa's do not like wet feet, being too wet will kill it quicker that not enough water. Also, do you plan to put it out side when it warms, they will do a lot better in outside.

Serissas can actually take a fair amout of cool temperatures, mine are exposed to upper 30's (F) quite often.

Hope it helps,

John

Oh, I see. Yeah, that would look better to have the side roots larger and grounded in the soil. How much of a power struggle would it be with the moss? I think it still has a little growing beneath the bark. I'm thinking I should remove all the moss, might as well if I got different soil. I was told that this is commercial bonsai soil the plant is potted in. So yes, I do think it is free draining (and yes, the pot itself is a bonsai pot). However I was thinking, this soil retains a lot of water for a Serissa. I got the plant on Sunday, and the soil is still moist enough that it does not need watering (I check weight, topsoil, and use the chopstick method). The soil mix seems to be quite high in humus matter, with some medium grit interspersed through out. With what sort of soil should I repot? In light of its trunk damage, would now be too stressful a time to repot?

Interesting. 30 degrees Farenheit? I have heard this elsewhere too. Has that ever caused your Serissa to drop leaves and flowers? Is there a maximum temperature I should be concerned with? Is 70 degrees Farenheit too hot? I've kept it in a humidity tray so far because the plant is by the windowsill in my room, but unfortunately it is right under a (closed) floor vent. A couple leaves are shriveled, but the rest are pretty healthy. Maybe it is the closed vent, maybe it is too much grow lamp (all day, a little more than a foot away), maybe it is stress. At college, my room is on the second floor and I don't trust leaving it out on its own. However, during my time at home in the summer, certainly I'll leave it out.

Thanks very much for your help, John. This is my first bonsai (I know, a Serissa?! What was I thinking.) and I want to do right by it.

Adam_San wrote:

However I was thinking, this soil retains a lot of water for a Serissa. I got the plant on Sunday, and the soil is still moist enough that it does not need watering (I check weight, topsoil, and use the chopstick method). The soil mix seems to be quite high in humus matter, with some medium grit interspersed through out. With what sort of soil should I repot? In light of its trunk damage, would now be too stressful a time to repot?

Considering that you are about to move it again, I would wait until summer break to repot. Just let the soil get dry (the chopstick should feel entirely dry) before you water -- thoroughly -- again.

Interesting. 30 degrees Farenheit? I have heard this elsewhere too. Has that ever caused your Serissa to drop leaves and flowers?

Yeah, but they'll grow back if you water carefully.

Is there a maximum temperature I should be concerned with? Is 70 degrees Farenheit too hot?

No and NO.

The humidity tray is actually a bit dangerous as it can keep the lower part of the soil too damp. Ditch it. An occasional misting (maybe once every afternoon) might be beneficial.

Adam,

I agree with Jim, just wait until Summer break to repot, that away you can offer it a more stable enviornment after repotting. Like he said, just make sure to let it dry before watering (damp, not desert dry). Ditch the humidity tray, it can keep the bottom layer of the pot too moist, and, it does little or nothing to increase the humidity anyway. It would have to be big enough to increase the humidity in the whole room.

As for soil, I don't know what is available to you in your area. I use a standard (for me) mix of 60% lava and or turface and 40% crushed pine bark. Google Turface and see if someone sells it in your area, get the MVP. I get the pine bark at Lowe's, Evergreen soil amendment, about three bucks for a huge bag.

Yeah, they drop some or most of their leaves in the cold, but they will do the same thing if I bring them inside, so it doesn't really matter. I have some on my bench that are bloming now and have been left out for a few dips in the upper 30's and a few days of 40 degree weather. I usually don't leave them out if it is gonna get below 30. It never really stays cold for too long here in Moblile, Alabama.

70 isn't too hot, in the summer, it gets and stays in the upper 90's consistantly and they do OK. I do have them shaded from the afternoon sun. It is the lack of humidity that you shuold be more concerned about, since it is inside.

The moss is OK on top of the soil, and it looks kinda nice, just keep it off of the surface roots and the trunk.

For me serissa is not as fickle as most say, and I think that they have an undeserved bad reputation. In fact, they grow like weeds. If you want a couple more just stick your trimming in some soil, they root easy too. I have had trimmings that were left on top of the soil root by themselves.



John

Not dry, just slightly damp. Got it. When I do repot in the summer, ought I start the process when the plant is "drying" or when it was recently watered? With misting, I have read that it may rot the flowers. Does that happen with Serissa? Now that I think about it, maybe poor humidity is why a few of the leaves have shriveled.

John, I think I will try your soil mix. Thanks for sharing. Haha, I do get that impression about Serissa - dramatic, but hardy. I think I'll let it grow some, and then save the trimmings when I prune. Could be fun to get some little ones started.

I find retail and wholesale bonsai sellers to be very misleading. You tree is an Chinese import, brought in with no soil, and potted by a importer in the US. The soil he used is the cheapest stuff he could find. It is only "Bonsai Soil" because he plants bonsai in it, we would not use it for bonsai. Yellow leaves are frequently a sign of being too wet. As someone already said Serissa can tolerate some cold, they are not tropicals.

I wasn't expecting a tree of the highest quality, just something to work with. I can at least say I did not spend an unmentionable amount of money on it. Serissa is subtropical, yes? I seem to recall that variations of Serissa have different traits. Would you happen to know the particulars about the Chinese variety?

Not many leaves are yellowing - should I take that as a sign that at least some drainage is occurring? Would you agree that it should be repotted in the summer, or is this a more time-sensitive problem? There is some grit in the soil to help with drainage.

There is greater danger from the Serissa being inside 24/7 then anything else. Just give it as much light as possible and watch the watering.

BTW, as Jim Lewis said there is only one kind of Serissa, there might be a variegated form. It isn't a "Chinese Serissa" it is a Serissa imported from China.

Understood. Thanks Billy, I'll keep that in mind.

Jim is right there is one group called serissa foetida, but there are many different varieties. Some with vairgated foilage, pink flowers, purple flowers, white flowers, and "flore pleno" has double flowers. The ones imported from China are a variety that has slightly longer and narrower leaves, don't remember the name.

Ah, very cool. For anyone interested, I came across a summary of some of these varieties:
http://absolutebonsai.com/serissa_bonsai