Sun tolerance of tropical species in high desert

[luvinthemountains]

Salt Lake City is an arid, high desert environment, elevation about 4,700 feet at my location, at about the 41st parallel for reference.

The weather is looking good this week, and I am starting to think about how to position my tropicals when I move them outside. Last year, I had them on a covered deck under a clear polycarbonate roof, and they grew okay but not terrific. This year, I am considering letting them have sun for at least part of the day, and I wonder what experiences others have had with these species growing in full sun in similar climates to mine -

• ficus benjamina (various cultivars)
• ficus microcarpa (various cultivars)
• ficus burtt davyi
• ficus salicaria
• ficus rumphi
• ficus pertusa
• ficus burkei "puberla"
• shefflera arboricola
• bougainvillea glabra "pink pixie"
• portulacaria afra
• brazilian raintree
• escambron

Those last two I am not sure of the latin names!

One location gets about 6 hours of full sun, the other gets about 10 hours.

 

[Colorado]

I have ficus microcarpa, ficus benjamina, escambron, and buttonwood in my tropical collection. All grow very well in full sun here in Denver, which I would think is a pretty similar climate to yours. I have also previously grown Brazilian rain tree and portulacaria in full sun here too.

Definitely have to water them 2 or 3 times per day with that much sun exposure.

I do acclimate them slowly over a couple of weeks in the shade when I bring them outside in the spring. Doing that currently!

 

[luvinthemountains]

Definitely have to water them 2 or 3 times per day with that much sun exposure.

I believe it! luckily, I just had my sprinkler line for the back yard modified to allow for drip irrigation. If I was out there with a hose that often, my wife would kick me and the trees out!

I do acclimate them slowly over a couple of weeks in the shade when I bring them outside in the spring.

I always wonder if the intensity of my lights in the tent is enough to skip this step, but so far I have erred on the side of caution. They will go on the shady side of the deck at first, then the sunny side, and then finally out on the full sun benches.

Thanks, TJ, for chiming in!!!

 

[luvinthemountains]

Well, I settled on putting the tropicals in full sun this year. My observation, they did not do so great. Watering and fertilization was mostly the same as last year, when I had them under the polycarb roof and they grew pretty well. Leaf size and internode length were better in full sun, but the trees all grew a lot more slowly, which makes me think they were stressed from the high UV at my elevation.

Another observation, I moved them all back under the cover of the deck a few weeks ago (due to grasshoppers mobbing my ficus trees), and they all started growing again. That could just have been due to the lower temperatures and higher humidity of late summer. But the burtt davyi stayed in full sun a couple weeks longer, and it did not start pushing growth until I moved it to the deck, so it seems plausible that it was due to the sun exposure.

Maybe next year I should put some in full sun and some under cover, and make some comparisons.

 

[Colorado]

Hm, interesting. I am at 6,000 feet and mine did great all summer. Maybe it has to do with your soil mix and/or watering? At the end of the day, we all have to do what works best in our particular garden

 

[luvinthemountains]

Hm, interesting. I am at 6,000 feet and mine did great all summer. Maybe it has to do with your soil mix and/or watering? At the end of the day, we all have to do what works best in our particular garden

That is interesting. It really could be my soil mix. (Or water quality - mine has pretty high PH, around 7.6.) For soil, I have been using a lot of pumice and scoria, with some bark mixed in. Going forward, I have been thinking I will significantly increase the ratio of bark to inorganics in my mix. Maybe akadama instead of additional bark for some of my trees. I will just play around with different things and see what works best.

 

[jevanlewis]

I have a ficus microcarpa that my mom bought for me because she knew I was in to bonsai. I basically treat it as a neglected indoor houseplant in the colder months and put it outside (and neglect it) during the warmer months. All I do is water it and give it fertilizer weekly when I fertilize my bonsai I actually like. It gets watered with both high PH water (irrigation lines) and low PH water (from the water softener). It's in the original pot and soil (looks like 100% coco coir) in a round, deeper-than your typical bonsai pot. When outside, it gets around 3-4 hours of morning sun. I have never pruned it (I've had it 2 years). The ficus has done fine considering the neglect. Like you, I am also getting new growth in the past few weeks as we've moved out of the hottest months.

At some point, I do want to repot it in a mix with more inorganic media and start pruning it. But, it's probably just going to get neglected some more.

 

[luvinthemountains]

I have a ficus microcarpa that my mom bought for me because she knew I was in to bonsai. I basically treat it as a neglected indoor houseplant in the colder months and put it outside (and neglect it) during the warmer months. All I do is water it and give it fertilizer weekly when I fertilize my bonsai I actually like. It gets watered with both high PH water (irrigation lines) and low PH water (from the water softener). It's in the original pot and soil (looks like 100% coco coir) in a round, deeper-than your typical bonsai pot. When outside, it gets around 3-4 hours of morning sun. I have never pruned it (I've had it 2 years). The ficus has done fine considering the neglect. Like you, I am also getting new growth in the past few weeks as we've moved out of the hottest months.

At some point, I do want to repot it in a mix with more inorganic media and start pruning it. But, it's probably just going to get neglected some more.

Hey there! So we are getting similar results within a few miles of each other. Our summer was pretty hot!