I would not have believed it if I had not seen it with my own eyes. I went to Opelousas Louisiana "Zone 8" to pick up a pear tree for my orchard and just happened to walk under the carport of this man’s house to witness three Satsuma’s growing underneath a metal roof. Honestly these three trees are growing underneath a metal roof.
I questioned the guy about this and he told me that the trees had been under the metal roof for several years. His house had an open garage with a storage area in the back, which was open on two sides. The Satsuma’s were planted on the side of the storage area. Later a roof was extended from the original garage and storage area outward to approximately 20’x24’. This put the three trees completely under a metal roof. The tree nearest the edge is 2’ (outer branches) inside the cover of the roof and the third tree is approximately 12’ from the edge of the roof. Proportionally the trees are smaller, the farther they are from the edge of the roof, but all are healthy and have to be trimed to the 10’ height of the roof.
All of the leaves of these trees are a very dark green color and I suppose this is due to the lack of direct sunlight.
The tree nearest to the edge of the roof does produce a few fruit, but I noticed that the tree furtherest from the edge had a few nickel size fruit
It’s hard to believe that these trees have survive the colder climate of this area not to mention surviving under a metal roof
If I get a chance I will return and take pictures in a couple of weeks. Unbelievable!
Karl

This simply means that a little overhead help could definitely help your satsuma. You can purchase corrugated polycarbonate roofing from Home Depot on the cheap. Make a strong structure to hold them over the satsuma and wider area than satsuma, no need to cover the sides. The polycarbonate lasts a long time, like 15 years on the average.

Not surprising, as citrus only require 1/3 of normal daily light to reach maximum photosynthesis. Here is a extremely interesting study that shows how a citrus tree reacts to shading.

>>> This study investigated the effects of shading on the growth and development of citrus trees in a warm subtropical region. The experiment was conducted from mid-June until late October when daily maximal air temperature averaged 29.3 °C. Two-year-old de-fruited Murcott tangor (Citrus reticulata BlancoxCitrus sinensis (L.) Osb.) trees were grown under 30% or 60% shade tunnels, or 60% flat shade (providing midday shade only), using highly reflective aluminized nets. Non-shaded trees were used as the control. Shading reduced direct more than diffuse radiation. Daily radiation was reduced by 35% for the 30% Tunnel and 60% Flat treatments, and by 55% for the 60% Tunnel. Two days of intensive measurement showed that shading increased average sunlit leaf conductance by 44% and photosynthesis by 29%. Shading did not significantly influence root and stem dry weight growth, but it increased the increment in leaf dry weight during the three month period by an average of 28% relative to the control, while final tree height in the 30% Tunnel treatment exceeded the control by 35%. Shoot to root and shoot mass ratios increased and root mass ratio decreased due to shading because of the increase in leaf dry weight. Shading increased starch concentration in leaves while the shadiest treatment, 60% Tunnel, decreased starch concentration in the roots. Carbon isotope ratio (13C) of exposed leaves that developed under shading was significantly reduced by 1.9 in the 60% Tunnel, indicating that shading increased CO2 concentrations at the chloroplasts (Cc), as would be expected from increased conductance. Substomatal CO2 concentrations, Ci, computed from leaf net CO2 assimilation rate and conductance values, also indicate that shading increases internal CO2 concentrations. Based on tree dry mass, tree height, and total carbohydrates fractions, the 30% Tunnel and the 60% Flat were the optimal shade treatments<<<
Millet

Thanks Millet.
Wondering if someone could break this down to layman's terms LOL
Sounds like some shading is good?