Pomegranate (Punica) -- asking questions first, pruning later

sparklemotion

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I picked up this pomegranate at the MN Bonsai Society Auction this past weekend. I'd like to keep it happy/healthy over the next few months before I start making any major decisions.

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I've read some of @bonhe's great threads on these trees, as well as some other online sources (b4me, bonsai empire) but I'm still a little confused.

1. Do these trees need any sort of winter dormancy? I'm in zone 4, and the instructions I got with the tree say to "winter indoors" and that what's considered normal cold frame storage for tender temperates around here (37-40°F/3-5°C) will kill them. My tropicals are getting 18hrs of full spectrum fluorescent daily (T5 HO) in a basement that won't go below 65°F/18°C). Will this tree be happy being treated like a tropical evergreen until spring?

I know that they will drop leaves in the fall when grown in zone -- should I defoliate to simulate that? Should I be keeping it outside right now while the days are still around 50-60°F?

2.) What about humidity? I'm already playing games by keeping a bougainvillea (desert) and a ficus (rainforest) on the same shelf, but if the punica prefers one or the other, I might try to play with microclimating a little.

3.) What about pruning/pinching for maintenance and/or ramification? The instructions I got said to "let grow then prune back hard to encourage branching." How far should I be letting these shoots go? I am pretty sure this tree hasn't seen pruning since it was repotted this past Spring. If it were going to go dormant, I would leave it alone. But if it's going to grow under lights all winter, I wouldn't mind getting some of those upper shoots under control.

4.) Is there a good resource for varietal identifiers? The label said "pomegranate" but I'd love to at least get the species right (if not the cultivar). What should I be looking for besides fruit/flower color?
 

bonhe

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sparklemotion, post: 497848, member: 22180"]I picked up this pomegranate at the MN Bonsai Society Auction this past weekend. I'd like to keep it happy/healthy over the next few months before I start making any major decisions.

1. Do these trees need any sort of winter dormancy?

I think you need to protect it in the cold winter, otherwise its branches will die off.

I know that they will drop leaves in the fall when grown in zone -- should I defoliate to simulate that?
I don't think you need to do that. I am living in zone 11, its leaves will turn yellow and drop soon!

Should I be keeping it outside right now while the days are still around 50-60°F?
I would pay attention to night temperature. If temp goes down to 0 C, I would put it inside

2.) What about humidity? I'm already playing games by keeping a bougainvillea (desert) and a ficus (rainforest) on the same shelf, but if the punica prefers one or the other, I might try to play with microclimating a little.
It prefers dry to wet.

3.) What about pruning/pinching for maintenance and/or ramification? The instructions I got said to "let grow then prune back hard to encourage branching." How far should I be letting these shoots go?
I don't do pinching. I do pruning, bending (through interlock technique). I wait until the new shoot turns color from red-green to ivory, then I prune back to 2 -3 leaves depending on the area of that branch.

4.) Is there a good resource for varietal identifiers? The label said "pomegranate" but I'd love to at least get the species right (if not the cultivar). What should I be looking for besides fruit/flower color?
Even though I have so many pomegranate in my yard at this time, I still can not recognize some of my trees! I also try to look for information on the internet, but nothing! As you may know, there are more than 1oo kinds of pomegranate in the world, and that is why we don't have much information about! Beside the fruit/flower color, I also use kind of flower (single or multiple layers), trunk type (twisted or untwisted); color, size, cuticle, shape of leaves; behavior of the branch (soft, stiff).
Hope it will help.
Bonhe
 

Leo in N E Illinois

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Welcome to the forum.
I grew up in Chicago, started a pomegranate way back last century while still in high school, living in Chicago. I kept that tree alive for 38 years. It was my beginner tree, I made all the major bonsai mistakes on it. As a result when it went to the compost heap at the age of 38 it still looked like a crappy amateur bonsai bush, but it had great texture to the trunk and branches. Point is, this species is a good beginner tree because they will bounce back and put up with all manner of abuse.

The first 20 years I had the pomegranate, I wintered it with my orchids, all winter somewhere in the 60's F at night, 18-20 C at night. Then the second 18 years I grew it, I would leave it out to get several hard frosts. 29 F is no problem at all. This will knock the leaves off forcing the tree to go completely dormant. I would then store it in a space that had no light, but stayed 32 to 39 F all winter. Usually about a month before it was warm enough to put outside (March) it would start growing in the well house. I would then put it with the orchids until safe to go outside. I would then have to cut off all growth that had sprouted indoors, because it was not as compact, or as strong as branches grown in full sun outdoors.

So pomegranate can handle being treated like a tropical (too warm in winter) but you won't get good strong flush of growth in spring. Growth will tend to have long internodes and be relatively weak. All ''winter growth'' will probably have to be removed every year.

Pomegranate can handle frost to 29 F absolutely no problem. They will be killed outright if the pot freezes to temperatures below about 25 F. This was how I lost my tree. It did not survive +19 F (- 5 C). It tried to grow, but I think roots were too heavily damaged.

Pomegranate, when leafless after being left outside to experience autumn cool down and transition to dormancy can stay dormant in cold frame, well house, garage for 3 months easily, sometimes 4 months, but at some point they will start growing, then it will be time to return to brightest location possible until safe to put outside. Light garden has to be brighter than what Vanda orchids would require to get strong growth. At ''Cattleya bright'' growth will be spindly. On the bright side of what marijuana growers use is what they need. The marijuana magazines and forums always have the latest on high intensity grow lights, as they have the money to test new technology.

Growth in spring outdoors, after having spent 3 months dormant is far superior to spring outdoor growth after being wintered at +60 F. Something about the cold dormancy that really improves the vigor of the pomegranate.

Pomegranate are survivors, if accidentally allowed to get dry in middle of summer, leaves may fall, but within a couple weeks new growth will resume. I've had mine recover from 5 days bone dry in middle of summer.

So enjoy. You can keep it going by wintering it with your orchids. And it will work for a decade or two. But you will be much, much happier with the growth if you winter it between 32 F to 40 F.

Do not let it get too cold. Somewhere below 25 F it will be fatal. I suggest keep them at or above 29F. Do let them cool down and go dormant in autumn. If they have had a couple light frosts, but haven't dropped all leaves, go ahead and defoliate. Then store cold.

Hope this helps.
 
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