Selecting a shade cloth

[Ugo]

Hi!

Hope everyone is doing well.

Question about shade cloth.

I ordered 45 cultivars of Azalea that will be here in March 23'
In order to be ready I have to prepare my backyard.
I live in Zone 5b but my backyard is under the sun all day long except for 1pm to 2pm where the neighbour tree provide some shade.

I decided to buy a pergola 16x10ft and install benches under it but Im now looking to buy a shade cloth to go on top of the pergola.

As Im not familiar with all the details of it Im seeking for advises on what to buy in term of color and shade % of the cloth.

I mainly want to protect my azalea and maples as they need protection from about 10am to 1pm and from 2pm to 4pm.

Im using 2 layers of window mesh as a suncloth to protect a part of my actual small collection with good success.
Anybody knows the % of shade this can provide?

Thanks for your help
Ugo

 

[Pitoon]

50% shade cloth will be sufficient

 

[Bonsai Nut]

I might even go as low as 30%. You just want a bare amount of screening. Also, with 30% you don't need to worry about the wind - the higher you go the more likely you will have problems during a storm.

 

[Glaucus]

The main issue will be pots and soil heating up. The azalea leaves will very likely take all the sun fine. Besides the heating of the soil, a shade cloth will also make it so that you don't need to water 2 or 3 times a day on sunny summer days. Especially for azaleas in 100% kanuma, when they are exposed completely, they will dry out pretty fast. If you could water them very regularly, they would be perfectly fine. However, this may not be practical.

If you were growing azaleas in the full ground and further south, I would get a 30% shade cloth. For azaleas in pots, I would get 50% shade cloth. And at your location for optimal growth on very healthy plants, you'd likely want to avoid using it on cooler summer days or partially cloudy or rainy summer days.
However, from my experience more shade is a low stress condition that still provides ample growth, which benefits somewhat stressed out plants greatly.
Roots warming up too much, getting a bit too dry, inside a small pot can definitely make an azalea stressed out.
However, if you can keep the roots moist and cool, they will take all the sun your climate can provide.

 

[Glaucus]

Ah the colour. I would just go with white. That's what I use as well. But apparently there is a whole bit of science on the specific effect of certain colours.
There is also this interesting article:

Homing in on the ideal environment for satsuki azaleas - Bonsai Tonight

To grow or not to grow in a greenhouse - that is the question for satsuki this season.

bonsaitonight.com

 

[Deep Sea Diver]

Sounds like a good solution. Having screening atop a pergola would greatly lessen the heat and ventilation issues That come from greenhouses.

It would totally be a guess as to the effectiveness of the pergola window screening. From experience, using window screening on my new cuttings, I’d guess each layer would be 15-20%. Overlapping isn’t a perfect additive result, due to placement and overlapping of the mesh fibers. So somewhere in the 35% rage would be a good guess. So 30% ought to do the jo if the screening is effective.

That said, any screening will be a bit more effective as the days draw past the solstice due to the daily azimuth angle being lower each day.

cheers
DSD sends

 

[Ugo]

Hi!

Thanks everyone for chimming in!

I decided to go with 30% and starts from there.
So far this combination works for my other trees.. I would need to test different % of shade but so far my most fragile trees are growing healthy without burning so I guess it work!

I had a talk with the oracle (my wife...) there's is not way she will accept a white shade...
Black it will be (You sometimes have to choose your battles!)

Here's some picture of the beast!
My original plan was to put the shade cloth on top of the pergola and still keep the 100% shade..
I think I can do a better setup if I remove the 100% shade actually installed, install a 30% shade on the railing and keep the ability to open and close it depending on the sun intensity.

 

[Bonsai Nut]

I decided to go with 30% and starts from there.

That's what Brad Russell uses at Bonsai Learning Center (a local bonsai spot). It is surprising how much it cuts the heat of the day why still allowing a lot of radiation through.

In Southern California I used 60% - but that is for intense, tropical sun. Even then, I found that the shade was more than adequate, but I was still crisping leaves on delicate deciduous trees due to low humidity and high wind.