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Growing Crimson Mandevilla In A Trough - I Need Some Advice

Hi - I have an 8'W x 7'H, large opening, lattice fence that I want to cover with this plant. I'd like to use a trough. The trough is 6' L, 2"W. They come in depths of 1'H and 2'H.. Will 1' be deep enough for this plant to grow to 7' high and maintain good health ? Can I put 4 plants in it or limit it to 3? I've read elsewhere that the plant should be granduated into larger pots as it grows. Would I not have good results if I immediately transplanted the plants into the trough rather than graduating them ? I've read elsewhere that using rotting wood to fill some of the container would provide a steady supply of nitrogen and cut down on soil costs for such large containers. I've also read about people using soda bottles and cans as filler which seems like a good recycling idea but wonder about plastic decomposing and it's impact on plant growth. I'm really in the dark as to how much room this plant will need for it's root ball. I've heard that they can get quite large. I want to provide the optimal environment for these plants so that they will cover this lattice nicely but I also don't want to spend excessive amounts of cash if it's not necessary. Any input on soil components would also be helpful. I'm really very inexperienced with gardening.

Thanks very much for your input. - Brian

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The trough is 6' L, 2"W.
I hope the trough is really 2' wide, and not just 2". The former would probably be okay, but the latter would be much too narrow.

According to what I've read, one plant needs at least 1 gallon of soil for adequate growth. Since the upper part of each plant grows to two feet wide, the roots may need more space to support that growth. If you provide sufficient and regular periodic fertilizer during the growing season, you might be able to get away with putting 4 plants in the trough. It could be an iffy situation, though.

I would go with the 2' deep trough. The more room you provide for the root system to grow large and strong, the healthier the plant will be. In addition, I think the 2' deep trough would be more aesthetically pleasing to the eye and look more balanced since the plants can grow to 8' tall. It's really your choice, though. Remember that if the 1' deep trough proved too shallow, transplanting the plants could be stressful on them by the time you discovered they needed more room.

Just my thoughts on the subject. :)

I know you live in a warm area, but these plants are supposed to be brought indoors for the winter in zones colder than 10. If that would apply to you, you might want to consider planting each plant in a separate container, for easier relocation.

Best of luck to you! :)

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Can't answer your trough question, though I think Kisal did a good job. But I agree that I was thinking Sonoma would still be too cold to leave it out all winter. But if it is all vined through a lattice fence, it could be difficult to bring in. I don't grow Mandevilla, because it can't be outside enough of the year where I am.

It looks like you are zone 8. Most people say mandevilla is hardy to zone 10 as Kisal said. I have seen it listed to zone 9. But I don't think it will winter over for you, outdoors.

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